Chemotherapy Nausea and CBD Oil: Research and Doses

What does the research say?

No controlled study of pure CBD in chemotherapy nausea was found. In a 144-person study of patients with advanced cancer receiving palliative care, pure CBD oil did not reduce symptoms, including nausea, more than an inactive oil (placebo); however, this study was not designed for chemotherapy nausea. Results obtained with THC-containing products also cannot be carried over to CBD oil.

A study of a capsule containing equal amounts of THC and CBD enrolled patients whose nausea continued despite standard anti-nausea medicines, and the patients were assigned to groups at random. The proportion of patients who did not vomit at all and did not need extra anti-nausea medicine in the 5 days after chemotherapy (complete response) rose from 8% with an inactive pill (placebo) to 24% with the capsule; a similar improvement was seen in the proportion of patients without significant nausea. The capsule was given in addition to standard treatment, not instead of it.

In Thailand, 54 patients with gynecologic cancer who were receiving chemotherapy used an oil containing equal parts THC and CBD during one chemotherapy cycle and a placebo during the other. The nausea score was slightly lower with the oil (2.11 vs. 2.99); however, two-thirds of the patients had dizziness and sleepiness. Because this product also contains THC, the result cannot be carried over to CBD oil.

Between 1975 and 1995, more than thirty studies were done with dronabinol, which is synthetic THC, and with the THC-like medicines nabilone and levonantradol. According to reviews that pooled these studies, these medicines reduced nausea and vomiting more than an inactive pill (placebo); compared with the anti-nausea medicines of that era, they gave similar or slightly better results, and most patients preferred them for their next chemotherapy. On the other hand, dizziness, low mood, feeling high and a drop in blood pressure were clearly more common. Comparisons with the medicines used today are very few: in a 61-person study, dronabinol gave results similar to ondansetron for delayed nausea. The American Society of Clinical Oncology (ASCO) states in 2024, as a weak recommendation, that THC-containing options can be added only for nausea that continues despite standard treatment.

In four small studies in children with nabilone and THC, these medicines mostly gave better results than the anti-nausea medicines of that era (prochlorperazine, metoclopramide, domperidone). The Cochrane review that examined these studies found the results very inconsistent with one another (in the largest study there was no difference in completely preventing vomiting); it wrote that cannabinoids are probably effective but that side effects such as sleepiness and dizziness are common. In a multicenter study that reviewed the records of 110 children given preventive treatment that also included nabilone, vomiting was completely prevented in about half of the children; the researchers considered this inadequate.

Studies on nausea during radiation therapy (radiotherapy) are very few, and all of them were done with THC or THC-like medicines. In a placebo-controlled study of 56 patients receiving radiation therapy for head and neck cancer, the THC-like medicine nabilone did not reduce nausea more than placebo; the main aim of this study was quality of life, and nabilone did not delay the decline in quality of life either. In a 1980s study of 40 patients with nausea during radiation therapy, nabilone was as effective as metoclopramide, an anti-nausea medicine of that era, but side effects such as dizziness, tiredness and disorientation were more common with nabilone. In a study comparing THC with prochlorperazine, THC was found slightly more helpful; but the study's abstract gives no number of participants and no numerical results. There is no study of pure CBD in radiation-therapy nausea. The UK's national guideline (NICE) did not find enough evidence to make a recommendation on this, and cannabinoids are not included in the 2023 recommendations of the international supportive cancer care societies (MASCC/ESMO) either.

Strength of evidence: ○○○○ Insufficient evidence. Finding: Not studied enough. What does this mean?

Ongoing research on this topic

Trials testing CBD for this topic on ClinicalTrials.gov: none under way; results are awaited from 1 that ended in the last two years. A trial being under way does not show that CBD works.

NCT03948074: Phase 2, completed, results awaited, 91 participants

All trials on this topic and their history

Possible side effects and drug interactions

With the THC-containing capsule, bothersome sleepiness (18% vs. 7%), dizziness (10% vs. 0%) and temporary anxiety were more common; no serious drug-related side effects were reported. In an analysis pooling 30 older studies published between 1975 and 1997, dizziness (49% vs. 17%), low or depressed mood, hallucinations, paranoia and a drop in blood pressure were more common with cannabinoids; stopping treatment because of side effects was about five times more common (11% vs. 2%). Feeling intoxicated (“high”) was also common.

CBD can slow the breakdown in the body of some medicines used in cancer treatment. For example, everolimus levels were shown to rise about 2.5-fold, and in a patient taking warfarin, the blood clotting value (INR) went up. In observational studies of people receiving immunotherapy, response to treatment was lower in those who used cannabis, mostly THC-containing; it has not been proven that this was caused by the cannabis.

Interactions with medicines used for this condition

Interactions reported for these medicines in peer-reviewed publications and official prescribing information. A medicine that is not listed can still interact with CBD; tell your doctor about every medicine you take.

Chemotherapy Nausea: medicines used and their interactions with CBD
Medicine	Importance	Warning	Source
Everolimus	High importance	Everolimus, sirolimus: In a controlled study in healthy volunteers taking approved CBD, the blood level of everolimus rose about 2.5-fold; in patients with TSC (tuberous sclerosis complex), everolimus and sirolimus levels rose in most patients when CBD was added. The prescribing information for both medicines recommends close monitoring of blood levels with CBD, and lowering the dose if needed. Do not start without talking to your doctor; your drug level should be monitored.	EMA Epidyolex SmPC 4.5, PMID 37132402, PMID 31924480, Everolimus (Afinitor) prescribing information §2.11 and §7.1, dailymed.nlm.nih.gov, Everolimus (Zortress) prescribing information §5.22 and §7.1, dailymed.nlm.nih.gov, Sirolimus prescribing information §5.21 and §7.5, dailymed.nlm.nih.gov
Warfarin	High importance	Warfarin: If you take warfarin, tell your doctor before starting CBD. Case reports have described INR rising and the warfarin dose needing to be lowered; more frequent INR monitoring is recommended.	PMID 29387536, PMID 33016308, PMID 30326170
Immunotherapy (checkpoint inhibitors, e.g., nivolumab)	Caution	Immunotherapy (checkpoint inhibitors): In some observational studies, cannabis users had a lower response to immunotherapy or shorter survival; other studies found no difference, and the results conflict. Cause and effect has not been proven, most studies were done with cannabis containing THC, and there are no data specific to pure CBD. Guidelines advise caution; do not start without talking to your oncologist.	PMID 30670598, PMID 32872248, PMID 35454955, PMID 38610922, PMID 39737331, PMID 36535195, PMID 40184324, PMID 38478773, PMID 36872397
Tamoxifen	Caution	Tamoxifen: In one case, the active breakdown product of tamoxifen (endoxifen) was found to be lower while the person was taking 40 mg of CBD a day. In a small study of 15 patients taking tamoxifen, about 50 mg a day of THC-free CBD oil lowered endoxifen by 12.6% on average; the researchers did not consider this difference important at this dose, and the effect of higher doses is not known. Do not start without talking to your oncologist.	PMID 33191836, PMID 37543688
Chemotherapy / cancer medicines (general)	Information	Chemotherapy and cancer medicines: Data on interactions between CBD and cancer medicines are very limited. Talk to your oncologist before using it.	PMID 30776990, PMID 38478773
Apixaban (DOAC), Rivaroxaban (DOAC)	Information	DOAC blood thinners: If you take a blood thinner, tell your doctor about CBD. There are no clinical data on interactions between these medicines and CBD; there is only a general warning in the package leaflet.	dailymed.nlm.nih.gov

To check interactions with the medicines you take: CBD drug interaction checker.

How was CBD used in studies?

Because there are no studies with pure CBD, there are no data on what dose of CBD oil might be used for nausea.

In the THC and CBD capsule study, each capsule contained 2.5 mg each of THC and CBD. Patients adjusted the dose themselves according to their nausea and side effects, from 1 capsule 3 times a day (study dose; not a personal recommendation) up to 4 capsules 3 times a day (study dose; not a personal recommendation). The capsules were started the day before chemotherapy and taken until the fifth day. These products are prescription medicines and are not the same thing as CBD oil.

In the 1975–1995 studies, nabilone was usually given as 1–2 mg 2–4 times a day (study dose; not a personal recommendation), and dronabinol as 5–15 mg/m² based on body surface area or as a fixed dose of 7.5–15 mg, 2–6 times a day (study dose; not a personal recommendation); the first dose was usually taken before chemotherapy. In children, nabilone was used at 0.5–2 mg based on weight, 2–3 times a day (study dose; not a personal recommendation). These medicines are prescription medicines and are not the same thing as CBD oil.

Study details (for health professionals)

No RCT of pure CBD in chemotherapy nausea was found. Current evidence comes from THC-containing products given in addition to standard treatment in patients whose nausea continued despite standard anti-nausea medicines: a 1:1 THC:CBD capsule raised the complete response from 8% to 24%. In gynecologic cancer, a 1:1 THC:CBD oil (very low dose) reduced the nausea score slightly more than placebo (54-person crossover RCT; 2.11 vs. 2.99); two-thirds of the patients had dizziness and sleepiness. The table includes 26 controlled studies done between 1975 and 1995 with dronabinol (synthetic THC) and nabilone (a synthetic THC-like cannabinoid) whose results can be read in their abstracts; 7 had a placebo group, and 19 compared only with the anti-nausea medicines of that era (prochlorperazine, metoclopramide, domperidone, etc.). Four controlled chemotherapy studies done in the same period with levonantradol, an experimental synthetic cannabinoid that was never approved, are not in the table under the site's rule and are mentioned here only as background: levonantradol was more effective than an anti-nausea medicine of that era (chlorpromazine, metoclopramide) in two studies, similar to prochlorperazine in one, and more effective than placebo in one; side effects such as low mood, sleepiness and a drop in blood pressure were common (Hutcheon 1983, PMID 6352278; Heim 1984, PMID 6467496; Sheidler 1984, PMID 6373843; Stambaugh 1984, PMID 6392353). According to reviews pooling the studies of this period, these medicines were better than placebo and similar to or slightly better than the anti-nausea medicines of that era; side effects and stopping because of side effects were more common (Tramèr 2001, 30 studies: complete control of nausea vs. the medicines of that era RR 1.38; Smith 2015 Cochrane: complete absence of nausea and vomiting vs. placebo RR 2.9, no difference vs. prochlorperazine; Chow 2025: vs. placebo RR 2.65, no difference vs. active medicines). The most recent review, examining 32 RCTs up to June 2024, rated no study as high quality and considered the evidence insufficient to recommend cannabinoids (Kemmner 2026). Compared with the strongest regimen of that era, high-dose metoclopramide plus dexamethasone, the nabilone regimen was less effective (Cunningham 1988); dronabinol added to an intensive anti-nausea regimen before bone marrow transplant gave no extra benefit (Gilbert 1995). Comparisons with today's medicines are few: dronabinol gave results similar to ondansetron for delayed nausea (Meiri 2007, 61 people, manufacturer-supported); with dronabinol added to palonosetron and dexamethasone, complete protection in the registry record was 35% vs. 16% (NCT00553059, 62 people; no statistical analysis and no peer-reviewed publication). In children there are 4 small RCTs with nabilone and THC; the results are conflicting and side effects are common (Phillips 2016 Cochrane). In radiotherapy nausea: during radiation therapy for head and neck cancer, nabilone did not affect nausea differently from placebo (Côté 2016, 56 people; nausea a secondary outcome, p = 0.71); in 40 patients with nausea during radiotherapy, nabilone was similarly effective to metoclopramide, with more side effects (Priestman 1987, crossover RCT); THC was found "slightly more helpful" than prochlorperazine (Ungerleider 1984; number of participants and statistics not in the abstract); levonantradol, an experimental synthetic cannabinoid, did not affect vomiting differently from chlorpromazine in single-session palliative radiation therapy (Lucraft 1982, PMID 6754212; not in the table because it is an experimental synthetic cannabinoid). There is no study of pure CBD in radiotherapy nausea. NICE's evidence review found only one study in radiotherapy nausea (Priestman 1987) and made no recommendation because there were no efficacy data; the MASCC 2022 review also counted only one RCT on this. In a recent RCT examining general symptoms in advanced cancer, pure CBD (MedCan1) did not reduce nausea more than placebo; this study was not designed for chemotherapy nausea. ASCO 2024 writes that THC-containing options may be added only in this refractory situation (weak recommendation). In the 1:1 capsule study, only 10% of patients had received olanzapine, and the study closed early with 151 patients instead of the planned 250. MASCC 2022 found the evidence insufficient to recommend cannabinoids for chemotherapy nausea; as reported by ASCO, the same document says they should not be used for first-line prevention but may be considered in refractory cases in patients not receiving checkpoint inhibitors. The MASCC/ESMO 2023 guideline on chemotherapy and radiotherapy nausea contains no recommendation for cannabinoids; the recommended medicine for nausea that continues despite standard treatment is olanzapine. The UK's national guideline NICE (2019, updated 2021) says nabilone may be considered as add-on treatment in adults for chemotherapy nausea that continues despite optimized standard anti-nausea medicines (NICE uses the word "consider" for recommendations where the benefit is less certain); its rationale is limited evidence, mostly from old and low-quality studies. It made no recommendation for other cannabis products or for children, and recommended research. October 2026 search (PubMed, Cochrane, ClinicalTrials.gov): 36 controlled studies with cannabinoids on this topic with readable results were found (35 in chemotherapy nausea, one of them with results only on ClinicalTrials.gov; one a pure CBD study on general symptoms in advanced cancer); all except the 4 with levonantradol are in the table below (one trial appears in two rows, with two separate publications; levonantradol is an experimental synthetic cannabinoid, so under the site's rule it is mentioned only in this text). Of the many systematic reviews examining this question, the 7 most recent and comprehensive (two of them Cochrane) and one observational study in children are also in the table. Eight older controlled studies with no abstract, or with no results in their abstract, could not be included in the table. In the October 2026 completion round, radiotherapy nausea was added to the page: 4 controlled studies with cannabinoids on this question were found; the 3 with THC or nabilone are in the table, and the one with the experimental synthetic cannabinoid levonantradol is only in this text under the site's rule; a comparative study published in Hebrew without an abstract could not be read. There are no cannabinoid registrations on ClinicalTrials.gov for radiotherapy nausea. The NICE guideline is also in the table. A single-arm study looking at the tolerability of dronabinol during chemotherapy in glioma patients (NCT00314808, 33 people) was not included because it had no comparison group and tracked nausea only as a secondary outcome, with a quality-of-life scale and without comparison.

Evidence assessment: Pure CBD: Insufficient; no RCTs in chemotherapy or radiotherapy nausea; in one RCT looking at general symptoms in advanced cancer, no difference from placebo for nausea

CBD alone

There are no controlled studies of pure CBD oil in chemotherapy or radiotherapy nausea; there is no evidence for CBD oil. In the only pure CBD study looking at general symptoms in advanced cancer (144 people, placebo-controlled), CBD did not reduce any symptom, including nausea, more than placebo; this study was not designed for chemotherapy nausea.

Products containing THC

A 1:1 THC:CBD capsule, oil or mouth spray added to standard anti-nausea medicines gave better results than placebo for nausea or vomiting in three recent RCTs (two of them in patients whose nausea continued despite standard treatment; the largest had 147 people). According to reviews pooling the controlled studies from 1975–1995, synthetic THC (dronabinol) and the THC-like medicines nabilone and levonantradol were better than placebo and similar to or slightly better than the anti-nausea medicines of that era; dizziness, feeling high and low mood were more common. Comparisons with today's medicines are very few: dronabinol gave results similar to ondansetron for delayed nausea (61 people); the result for dronabinol added to palonosetron and dexamethasone exists only in a ClinicalTrials.gov record, without statistical analysis. When added to an intensive, older-type anti-nausea regimen given before bone marrow transplant, dronabinol gave no additional benefit. For radiation-therapy (radiotherapy) nausea, the evidence is very limited and mostly old: nabilone was no better than placebo (56 people; nausea a secondary outcome) or metoclopramide (40 people), and had more side effects than metoclopramide; THC was found slightly more helpful than prochlorperazine in one study (number of participants and statistics not in the abstract). These results cannot be carried over to CBD oil.

Evidence: Weak (our assessment: most of the studies were done before today's anti-nausea medicines). ASCO 2024 (Recommendation 3.1): quality of evidence moderate for dronabinol and nabilone, low for 1:1 THC:CBD extract; strength of recommendation weak. NICE 2019: nabilone may be considered as add-on treatment in adults only for chemotherapy nausea that continues despite optimized standard treatment. For radiotherapy nausea, very weak (3 controlled studies, two of them from the 1980s; no difference in two; number of participants 56 and 40 in two, not given in the abstract in one)

Dose range in studies

No pure CBD studies in chemotherapy nausea; THC-containing 1:1 capsule from 2.5 mg THC + 2.5 mg CBD 3 times a day up to 10 mg + 10 mg 3 times a day; in older studies, nabilone 1–2 mg 2–4 times a day, dronabinol 5–15 mg/m² 2–6 times a day

Starting dose and titration

In the THC:CBD capsule studies, patients adjusted the dose themselves according to nausea and side effects

These are doses researchers gave under medical supervision; they are not a recommended dose for you. "mg/kg/day" means milligrams per kilogram of body weight per day.

Chemotherapy Nausea and CBD: studies reviewed
Study	Participants	Product	Dose and titration	Duration	Result	Source
Grimison 2024 (CannabisCINV phase II/III) Double-blind, placebo-controlled RCT (combined analysis)	151 randomized, 147 treated, 144 in the efficacy analysis (250 planned; closed early because of slow recruitment) Refractory nausea and vomiting despite moderately/highly emetogenic IV chemotherapy + guideline-consistent prophylaxis	Capsule: THC 2.5 mg + CBD 2.5 mg (1:1)	1 capsule 3 times a day → 4 capsules 3 times a day (THC 10 mg + CBD 10 mg/dose); median 2 capsules/dose (5 mg THC + 5 mg CBD 3 times a day) By the patient, according to nausea and side effects	Day −1 to day 5 (chemotherapy cycle)	Complete response 8% → 24% (absolute difference 16%; 95% CI 4–28; p=0.01) Side effects: Moderate/severe: sedation 18% vs. 7%, dizziness 10% vs. 0%, anxiety 4% vs. 1%; adverse effects of any severity 74% vs. 38%; no drug-related serious side effects	PMID 39151115, doi:10.1200/JCO.23.01836, PMID 32801017, separate row in the table, PMID 30209152
Grimison 2020 (phase II, crossover) Double-blind, placebo-controlled crossover RCT	81 randomized, 72 in the efficacy analysis Refractory chemotherapy-induced nausea and vomiting	Capsule: THC 2.5 mg + CBD 2.5 mg (1:1)	1 capsule 3 times a day → 4 capsules 3 times a day By the patient	Day −1 to day 5	Complete response 14% → 25% (RR 1.77; 90% CI 1.12–2.79); 83% of patients preferred cannabis Side effects: Moderate/severe cannabinoid side effects in 31% (sedation, dizziness, disorientation)	PMID 32801017, doi:10.1016/j.annonc.2020.07.020, First part of the same phase II/III trial, PMID 39151115
Sukpiriyagul 2023 Double-blind, placebo-controlled crossover RCT	54 analyzed (60 enrolled) Women with gynecologic cancer receiving moderately to highly emetogenic chemotherapy (Thailand)	THC:CBD 1:1 oil (2.7 mg THC + 2.5 mg CBD per mL), in addition to standard anti-nausea medicines	1 drop under the tongue twice a day (days 1–3), 3 times a day (days 4–5)	5 days in each chemotherapy cycle (2 cycles)	Nausea score 2.11 with the oil and 2.99 with placebo (p<0.05) Side effects: Dizziness and sleepiness in 36 of 54 people; dry mouth, confusion, anxiety and palpitations similar between groups	PMID 37608911, doi:10.2147/IJWH.S401938
NCT00553059 (MD Anderson, registry results) Randomized, triple-blind, placebo-controlled parallel study (phase 3)	62 randomized (31 dronabinol, 31 placebo); 59 completed Adults with solid tumors receiving moderately emetogenic chemotherapy (cyclophosphamide and/or doxorubicin) for the first time (USA)	Dronabinol (synthetic THC) tablet; both groups received palonosetron and dexamethasone	5 mg 3 times a day for 5 days (first dose 30 minutes before chemotherapy)	First 5 days of the first chemotherapy cycle	Comparison: placebo; both groups received palonosetron + dexamethasone (a 5-HT3 antagonist and a corticosteroid; no NK1 antagonist or olanzapine was given). The primary outcome, complete protection (no vomiting, no rescue medicine and no nausea over 5 days), was achieved in 11 of 31 people (35%) with dronabinol and 5 of 31 (16%) with placebo; in the first 24 hours, 22 vs. 14. No statistical analysis in the registry; in a secondary outcome with the same definition the numbers differ (14 of 30 vs. 9 of 29), and the numbers for some secondary outcomes are internally inconsistent. No peer-reviewed publication; according to the registry, the co-sponsors were the US National Cancer Institute and the dronabinol manufacturer Solvay Side effects: Dizziness in 14 of 30 people (placebo 7 of 29), insomnia 15 vs. 4, tiredness 17 vs. 11, sleepiness 5 vs. 3; serious side effects in 1 person in each group	NCT00553059, October 9, 2020, no publication found on PubMed in October 2026)
Duran 2010 Double-blind, placebo-controlled parallel pilot RCT (phase 2)	16 randomized (7 spray, 9 placebo); all analyzed Adults with solid tumors with nausea and vomiting lasting more than 24 hours after moderately emetogenic chemotherapy despite standard preventive treatment (Spain, 3 university hospitals)	Mouth spray containing THC and CBD (Sativex; each spray 2.7 mg THC + 2.5 mg CBD), in addition to standard anti-nausea medicines	On the first day, up to 3 sprays within 2 hours in hospital, then at home up to 8 sprays every 4 hours until day 4; mean 4.8 sprays a day (about 12.9 mg THC + 12 mg CBD) By the patient, according to side effects; no target dose	120 hours after chemotherapy (1 cycle)	Comparison: placebo; both groups received standard anti-nausea medicines (a corticosteroid and a 5-HT3 antagonist or metoclopramide). Complete response over the 120-hour period in 5 of 7 people (71%) with the spray and 2 of 9 (22%) with placebo; difference 49% (95% CI 1–75). The difference came from the delayed phase; in the first 24 hours 5/7 vs. 6/9. Very small pilot study; the primary aim was tolerability Side effects: At least one side effect 86% vs. 67%; most common was sleepiness; 1 patient stopped on the first day because of anxiety, sleepiness, visual hallucinations and confusion (resolved in 3 hours); no serious side effects	PMID 21039759, doi:10.1111/j.1365-2125.2010.03743.x
Meiri 2007 Double-blind, placebo-controlled parallel RCT (4 groups)	64 randomized; 61 in the efficacy analysis Delayed nausea and vomiting in adults receiving moderately or highly emetogenic chemotherapy	Dronabinol (synthetic THC) capsule; all groups received dexamethasone 20 mg and ondansetron 16 mg on day 1	Day 1: 2.5 mg before and after chemotherapy; day 2: 10 mg; days 3–5: 10–20 mg Flexible dose on days 3–5	5 days (chemotherapy day and the following 4 days)	Comparison: ondansetron (an anti-nausea medicine still used today), dronabinol + ondansetron, and placebo; on day 1 all groups received ondansetron and dexamethasone, and the comparison was for delayed nausea on days 2–5. Total response (nausea below 5 mm on a 100 mm scale, no vomiting and no rescue medicine) 54% with dronabinol, 58% with ondansetron, 47% with both, and 20% with placebo. No nausea at all in 71%, 64%, 53% and 15%, respectively (all three active groups better than placebo, p<0.05). Dronabinol and ondansetron gave similar results; giving both together gave no added benefit. Because of slow recruitment the groups remained small; according to the authors, this limits interpretation of the results. According to the registry, the sponsor was the dronabinol manufacturer (Solvay) Side effects: Active treatments were well tolerated; side-effect rates not in the abstract	PMID 17355735, doi:10.1185/030079907x167525, NCT00642512, 64 people and 2003–2004 period, sponsor Solvay Pharmaceuticals, no results in the registry)
Sallan 1975 Double-blind, placebo-controlled crossover RCT	22 patients; 20 evaluable Cancer patients receiving chemotherapy that causes nausea and vomiting	Oral delta-9-THC (the same substance as today's dronabinol)	Not in the abstract; according to Tramèr 2001, 15 mg or 10 mg/m², 3 doses	Several chemotherapy cycles (each patient served as their own control)	Comparison: placebo. An anti-nausea effect was seen in 14 of 20 THC courses and in none of 22 placebo courses; among those who completed the study, in 12 of 15 THC courses and none of 14 placebo courses (p<0.001). A very small and old study Side effects: Abstract states only: no patient vomited while feeling high	PMID 1099449, doi:10.1056/NEJM197510162931603
Herman 1979 Two double-blind crossover RCTs (reported together)	113 evaluable patients Cancer patients experiencing severe nausea and vomiting with chemotherapy	Nabilone (synthetic THC-like cannabinoid) capsule	Not in the abstract; according to Tramèr 2001, 2 mg 3–4 times a day	Two consecutive identical chemotherapy cycles	Comparison: prochlorperazine (the standard anti-nausea medicine of that era). Response in 90 of 113 people (80%) with nabilone and 36 (32%) with prochlorperazine (p<0.001); complete resolution of symptoms in only 9 people (8%, nabilone). Nausea (p<0.01) and the number of vomiting episodes (p<0.001) were lower with nabilone; patients preferred nabilone for continued treatment (p<0.001) Side effects: Sleepiness, dry mouth and dizziness similar in type with both medicines, but about twice as common and more severe with nabilone; side effects requiring medical intervention in 4 patients (3%) (hallucinations in 3, drop in blood pressure in 1); euphoria 16% and mild	PMID 375088, doi:10.1056/NEJM197906073002302
Chang 1979 Double-blind, placebo-controlled crossover RCT	15 patients Patients with bone cancer (osteosarcoma) receiving high-dose methotrexate	Oral THC; smoked THC (cannabis cigarette) if vomiting occurred	Not in the abstract; according to Tramèr 2001, 10 mg/m² by mouth, 4 doses	High-dose methotrexate cycles (each patient served as their own control)	Comparison: placebo. Nausea and vomiting decreased with THC in 14 of 15 patients; the number of vomiting and retching episodes, the degree and duration of nausea, and the volume of vomit were significantly lower than with placebo (p<0.001). The rate of nausea and vomiting with placebo was 72%; as blood THC levels rose, the rate of nausea and vomiting fell (44%, 21%, 6%) Side effects: Not in the abstract	PMID 293141, doi:10.7326/0003-4819-91-6-819
Kluin-Neleman 1979 Double-blind, placebo-controlled crossover study (randomization not stated in the abstract)	Not in the abstract; according to Tramèr 2001, 11 patients Lymphoma patients receiving MOPP chemotherapy	Oral THC	Not in the abstract; according to Tramèr 2001, 10 mg/m², 2 doses	MOPP chemotherapy cycles	Comparison: placebo. THC's anti-nausea effect was clear, but the side effects were severe and most patients preferred to put up with nausea and vomiting rather than take THC; no relationship was found between effect or side effects and blood THC levels. Numbers not in the abstract Side effects: Severe (details not in the abstract)	PMID 516362
Frytak 1979 Double-blind, placebo-controlled parallel RCT (3 groups)	116 patients Patients with gastrointestinal cancer receiving 5-fluorouracil and semustine; median age 61	Oral THC	15 mg 3 times a day	One chemotherapy cycle	Comparison: prochlorperazine 10 mg 3 times a day (an anti-nausea medicine of that era) and placebo. THC was more effective than placebo but had no advantage over prochlorperazine. In this mostly older patient group, THC treatment was overall a more unpleasant experience than prochlorperazine and placebo. Numbers not in the abstract Side effects: Central nervous system side effects significantly more common and more severe with THC	PMID 517882, doi:10.7326/0003-4819-91-6-825
Ekert 1979 (children) Two double-blind comparative studies; according to the Cochrane review in children, separate randomization for each chemotherapy course (RCT)	Number of children not in the abstract; according to the Cochrane review in children, 17 vs. 25 chemotherapy courses in the metoclopramide comparison and 18 vs. 18 in the prochlorperazine comparison Children receiving chemotherapy (various cancers; no cisplatin)	Oral THC	10 mg/m²; 2 hours before chemotherapy and at hours 4, 8, 16 and 24	Chemotherapy courses (24 hours)	Comparison: metoclopramide syrup and prochlorperazine tablets (anti-nausea medicines of that era). In both comparisons THC reduced nausea and vomiting significantly more, but it did not work in every child. Numbers not in the abstract; the Cochrane review in children confirms THC's superiority for nausea and vomiting Side effects: Sleepiness significantly more common with THC; feeling high in 2 children; increased appetite in some	PMID 231736
Sallan 1980 Double-blind crossover RCT	79 THC and 78 prochlorperazine cycles; number of patients not in the abstract (73 according to Tramèr 2001) Cancer patients receiving chemotherapy who had not benefited from standard anti-nausea medicines; including children and adolescents	Oral THC	Not in the abstract; according to Tramèr 2001, 15 mg or 10 mg/m², 3 doses	Chemotherapy cycles	Comparison: prochlorperazine (an anti-nausea medicine of that era). Complete response in 36 of 79 THC cycles and 16 of 78 prochlorperazine cycles. Of the 25 patients who received both medicines and stated a preference, 20 chose THC (p=0.005). Complete response more common in people younger than 20 (15 of 20 cycles). A feeling of being high was present in 32 of the 36 THC cycles with a complete response Side effects: Feeling high common; food intake increased more with THC (p=0.008)	PMID 6985702, doi:10.1056/NEJM198001173020302
Colls 1980 Double-blind crossover RCT (3 medicines)	Not in the abstract; according to Tramèr 2001, 35 patients Cancer patients receiving chemotherapy	Oral THC	Not in the abstract; according to Tramèr 2001, 12 mg/m², 2 doses	Chemotherapy cycles	Comparison: metoclopramide and thiethylperazine (anti-nausea medicines of that era). There was no significant difference in anti-nausea effect among the three medicines; the authors did not recommend THC at these doses for routine use Side effects: Side effects were significantly more common with THC in both staff and patient records	PMID 6250106, Report of the same study as a letter: Colls 1980, PMID 6104004, Tramèr 2001 counted it twice
Steele 1980 Double-blind crossover RCT	37 patients Cancer patients receiving various chemotherapies (high- or low-dose cisplatin, mechlorethamine, streptozocin, actinomycin D, DTIC)	Nabilone (synthetic THC-like cannabinoid)	2 mg every 12 hours	Chemotherapy cycles	Comparison: slow-release prochlorperazine 10 mg every 12 hours (an anti-nausea medicine of that era). Symptoms resolved completely or partly in 18 of 37 patients: in 7 with nabilone only, in 3 with prochlorperazine only, and in 8 with both. Nabilone appeared more effective with chemotherapies other than high-dose cisplatin; with high-dose cisplatin the two medicines were equivalent Side effects: Sleepiness and dizziness common with nabilone; dose-limiting in 25% of patients. With prochlorperazine, only mild sleepiness (35%)	PMID 6250699
Orr 1980 Double-blind, placebo-controlled crossover RCT (3 treatments)	55 patients Patients with various cancers who had previously had severe nausea or vomiting with chemotherapy	Oral THC	Not in the abstract; according to Tramèr 2001, 7 mg/m², 4 doses	Chemotherapy cycles	Comparison: prochlorperazine (an anti-nausea medicine of that era) and placebo. Patients with no nausea at all: 40 of 55 with THC, 8 with prochlorperazine and 5 with placebo (according to the second publication, p<0.005 between THC and prochlorperazine). THC appeared more effective with cyclophosphamide, 5-FU and doxorubicin, and less effective with mechlorethamine and nitrosoureas Side effects: Not in the abstract	PMID 6254456, doi:10.1001/archinte.140.11.1431, Second publication on the same 55 patients: Orr and McKernan 1981, PMID 6271846, Tramèr 2001 counted it twice
Chang 1981 Double-blind, placebo-controlled crossover RCT	8 patients Patients receiving doxorubicin and cyclophosphamide after surgical removal of a soft tissue sarcoma	Oral THC; smoked THC (cannabis cigarette) if vomiting occurred	Not in the abstract; according to Tramèr 2001, 10 mg/m² by mouth, 4 doses	Adjuvant chemotherapy cycles (each patient served as their own control)	Comparison: placebo. THC did not significantly reduce the number of vomiting and retching episodes, the volume of vomit, or the degree and duration of nausea compared with placebo. According to the authors, THC's effect varies with the chemotherapy drug (the same team had found an effect with high-dose methotrexate). Very small study Side effects: Not in the abstract	PMID 6261926, doi:10.1002/1097-0142(19810401)47:7<1746::aid-cncr2820470704>3.0.co, 2-4
Neidhart 1981 Double-blind crossover RCT (interim report)	52 evaluable patients (as of October 1980) Patients receiving chemotherapy causing severe vomiting (cisplatin, nitrogen mustard or doxorubicin) or who had retching with previous chemotherapy	Oral THC	Not in the abstract; according to Tramèr 2001, mean 10 mg, 4 doses	2 cycles with one medicine, then 2 cycles with the other	Comparison: haloperidol (an antipsychotic also used as an anti-nausea medicine). The two medicines were equally effective in terms of the number of vomiting episodes, the patient's assessment of effectiveness and preference; vomiting was completely controlled in about 10% of patients, and one-third had fewer than 5 vomiting episodes. In about half of those who did not respond to one medicine, the other provided good control Side effects: THC's side effects were tolerated less well than haloperidol's; no serious side effects in most patients	PMID 6271838, doi:10.1002/j.1552-4604.1981.tb02571.x
Einhorn 1981 Double-blind crossover RCT	80 evaluable patients Cancer patients receiving combination chemotherapy, mostly cisplatin-containing	Nabilone (synthetic THC-like cannabinoid)	Not in the abstract; according to Tramèr 2001, 2 mg, 4 doses	Two consecutive identical chemotherapy cycles	Comparison: prochlorperazine (an anti-nausea medicine of that era). 60 of 80 patients (75%) found nabilone more effective for nausea and vomiting; of these, the 46 who continued chemotherapy kept using nabilone. No statistical comparison between the medicines in the abstract Side effects: Drop in blood pressure and weakness more pronounced with nabilone; side effects did not prevent chemotherapy	PMID 6271844, doi:10.1002/j.1552-4604.1981.tb02576.x
Ungerleider 1982 Double-blind crossover RCT	214 evaluable patients (75% had previously received prochlorperazine) A wide variety of chemotherapy regimens and cancer types (USA, UCLA)	Oral THC	7.5–12.5 mg based on body surface area; 1 hour before chemotherapy, then every 4 hours, 4 doses in total	Chemotherapy cycles	Comparison: prochlorperazine 10 mg (an anti-nausea medicine of that era), on the same schedule. The two medicines reduced nausea and vomiting equally; no difference in appetite or food intake. THC's side effects did not reduce preference for it; patients who correctly guessed their THC period did better with THC (p<0.05) Side effects: With THC, reduced concentration (p<0.01) and reduced social interaction (p<0.05) and activity (p<0.05); drug-related effects more common with THC	PMID 6284334, doi:10.1002/1097-0142(19820815)50:4<636::aid-cncr2820500404>3.0.co, 2-4, Patient preference analysis of the same study: Ungerleider 1985, PMID 3010696, 139 patients, preference was determined mainly by reduction in nausea), Tramèr 2001 counted it twice
George 1983 Double-blind crossover RCT	20 patients Women with advanced gynecologic cancer receiving cisplatin-containing chemotherapy	Nabilone (synthetic THC-like cannabinoid)	According to the abstract, 3 mg 3 times a day, starting the day before cisplatin and ending the day after (1 mg × 3 in the Tramèr 2001 table)	Cisplatin cycles	Comparison: chlorpromazine 12.5 mg intramuscularly (an anti-nausea medicine of that era). Nabilone did not reduce the number of vomiting episodes significantly more than chlorpromazine. 10 patients preferred nabilone, 5 chlorpromazine, and 3 were undecided Side effects: Similar with both medicines: sleepiness, dry mouth, drop in blood pressure on standing; no intervention needed beyond reassurance	PMID 6311306
Ahmedzai 1983 Double-blind crossover comparative study	34 patients Patients with lung cancer receiving cyclophosphamide, doxorubicin and etoposide	Nabilone (synthetic THC-like cannabinoid)	Not in the abstract; according to Tramèr 2001, 2 mg twice a day	3-day chemotherapy cycles	Comparison: prochlorperazine (an anti-nausea medicine of that era). Nausea, retching and vomiting scores were significantly better with nabilone (p<0.05); fewer patients vomited (p=0.05) and there were fewer vomiting episodes (p<0.05); no patient on nabilone needed an extra anti-nausea injection. Most patients preferred nabilone (p<0.005) Side effects: With nabilone, sleepiness 57%, dizziness on standing 35%, lightheadedness 18%, euphoria 14%, feeling drunk 7%; standing systolic blood pressure lower on day 1, a significant problem in only 7%	PMID 6315040, doi:10.1038/bjc.1983.247
Niiranen 1985 Double-blind crossover RCT	24 patients Patients with lung cancer receiving chemotherapy	Nabilone (synthetic THC-like cannabinoid)	2 mg every 12 hours, starting the evening before chemotherapy	Two consecutive identical chemotherapy cycles	Comparison: prochlorperazine 15 mg every 12 hours (an anti-nausea medicine of that era). Nabilone reduced the number of vomiting episodes significantly more; two-thirds of patients preferred nabilone Side effects: Side effects in about half of patients with nabilone (mostly dizziness); 3 patients were withdrawn from the study because of incoordination and hallucinations. With prochlorperazine, only mild sleepiness in 1 patient	PMID 3002167, doi:10.1097/00000421-198508000-00013
Niederle 1986 Randomized crossover study (blinding not stated in the abstract)	20 patients Young men with non-seminomatous testicular cancer receiving low-dose cisplatin who had not previously received emetogenic chemotherapy	Nabilone (synthetic THC-like cannabinoid)	2 mg twice a day	Two chemotherapy cycles	Comparison: alizapride 150 mg 3 times a day (an anti-nausea medicine of that era). With nabilone, fewer vomiting episodes (median 1.1 vs. 2.9; p<0.01); complete absence of nausea more common (median 65% vs. 30%; p<0.01) and shorter duration of nausea (1.3 vs. 5.1 hours; p<0.01) Side effects: More side effects with nabilone	PMID 3009962, doi:10.1007/BF01728184
Crawford 1986 Double-blind crossover RCT	32 patients Cancer patients receiving cisplatin	Nabilone (synthetic THC-like cannabinoid), by mouth	1 mg every 8 hours	4 chemotherapy cycles (medicines in random order)	Comparison: intravenous metoclopramide 1 mg/kg every 3 hours (a strong anti-nausea medicine for cisplatin at that time). Overall, no difference in the frequency and severity of vomiting; in one subgroup, vomiting was clearly reduced with metoclopramide Side effects: Side effects expected from the known effects of the medicines (no details in the abstract)	PMID 3010011, doi:10.1007/BF02934575
Dalzell 1986 (children) Double-blind crossover RCT	23 eligible children; 18 completed Children aged 10 months to 17 years receiving repeated identical chemotherapy (various cancers; most high-dose cyclophosphamide)	Nabilone (synthetic THC-like cannabinoid)	By weight: under 18 kg 0.5 mg twice a day, 18–36 kg 1 mg twice a day, over 36 kg 1 mg 3 times a day	Repeated identical chemotherapy cycles	Comparison: oral domperidone (an anti-nausea medicine of that era). With nabilone, the number of vomiting episodes and nausea were significantly lower (according to the Cochrane review in children, nausea score on a 0–3 scale 1.5 vs. 2.5; p=0.01); two-thirds of the children preferred nabilone Side effects: Most common were sleepiness and dizziness; distressing hallucinations in 1 child	PMID 3013104, doi:10.1136/adc.61.5.502
Pomeroy 1986 Double-blind, randomized, two-cycle comparative study	38 patients; 32 cycles with nabilone and 33 with domperidone evaluated Cancer patients receiving highly emetogenic chemotherapy (70% cisplatin-containing)	Nabilone (synthetic THC-like cannabinoid)	1 mg; the night before chemotherapy and every 8 hours on chemotherapy days	Two consecutive chemotherapy cycles	Comparison: domperidone 20 mg (an anti-nausea medicine of that era). Mean number of vomiting episodes over both cycles combined 4.53 with nabilone and 10.81 with domperidone (p<0.01); 4.76 vs. 12.95 in the first cycle (p<0.02), difference not significant in the second cycle. No significant difference in nausea or food intake Side effects: More common with nabilone: sleepiness, dizziness, dry mouth, drop in blood pressure on standing	PMID 3017596, doi:10.1007/BF00256701
Chan 1987 (children) Double-blind crossover RCT	30 children Children aged 3.5–17.8 who had moderate to severe nausea and vomiting with previous chemotherapy (no cisplatin)	Nabilone (synthetic THC-like cannabinoid)	By weight, started 8–12 hours before chemotherapy, 2–3 times a day (0.5–2 mg according to the Cochrane review in children) A lower dose schedule was adopted during the study	Two consecutive identical chemotherapy cycles	Comparison: prochlorperazine (an anti-nausea medicine of that era). Overall improvement in retching and vomiting 70% with nabilone and 30% with prochlorperazine (p=0.003); 66% of children preferred nabilone and 17% prochlorperazine (p=0.015). The Cochrane review in children, however, found no difference in complete prevention of vomiting in this study (RR 1.0; 95% CI 0.85–1.17). The study was supported by the company that supplied nabilone (Eli Lilly) Side effects: Significant side effects (dizziness, sleepiness, mood changes) 11% with nabilone and 3% with prochlorperazine; more likely at doses above 60 micrograms per kilogram per day	PMID 3035479
Cunningham 1988 Randomized, open-label (unblinded) crossover study	80 patients; 70 completed the crossover Patients receiving cisplatin- or carboplatin-containing chemotherapy for the first time	Oral nabilone + prochlorperazine	Nabilone 2 mg + prochlorperazine 5 mg every 12 hours, 4 doses	First two chemotherapy cycles	Comparison: intravenous high-dose metoclopramide + dexamethasone 20 mg (the strongest anti-nausea regimen of that era). Complete control of nausea and vomiting 32% (24 patients) with metoclopramide + dexamethasone and 19% (14 patients) with nabilone + prochlorperazine; the vomiting score favored metoclopramide + dexamethasone (p=0.02). No overall difference in preference (31 to 26; 13 undecided); those receiving carboplatin preferred the nabilone regimen (16 to 5; p=0.013) Side effects: No details in the abstract	PMID 2838294, doi:10.1016/0277-5379(88)90300-8
McCabe 1988 Randomized comparative crossover study	36 patients Chemotherapy patients whose vomiting was resistant to standard anti-nausea treatment	Oral THC	15 mg/m²	Chemotherapy cycles	Comparison: prochlorperazine 10 mg (an anti-nausea medicine of that era). THC reduced nausea and vomiting in 23 of 36 patients (64%), prochlorperazine in 1. The effect did not vary by type of chemotherapy, age or type of perceptual change Side effects: Temporary perceptual changes in all patients: a pleasant feeling of being high in 19, low mood and restlessness (dysphoria) in 17	PMID 2847994, doi:10.1007/BF00175407
Lane 1991 Double-blind, multicenter parallel RCT (3 groups)	Not in the abstract; according to Tramèr 2001, 54 patients (17, 20, 17) Cancer patients receiving chemotherapy	Dronabinol (synthetic THC), by mouth	10 mg every 6 hours	From 24 hours before chemotherapy to 24 hours after the last dose	Comparison: prochlorperazine 10 mg every 6 hours (an anti-nausea medicine of that era) and the two given together. After chemotherapy, nausea occurred in 29% with the combination, 47% with dronabinol and 60% with prochlorperazine; vomiting in 35%, 41% and 55%, respectively. The combination was significantly more effective than either medicine alone Side effects: Mostly central nervous system side effects; more common with dronabinol alone than with prochlorperazine; adding prochlorperazine reduced dronabinol's dysphoric effect	PMID 1652611, doi:10.1016/0885-3924(91)90026-z, Preliminary report of the same trial: Lane 1990, PMID 2173391, 19 patients, 17 evaluable), Tramèr 2001 counted it twice
Gilbert 1995 Double-blind 2×2 factorial RCT (4 groups)	126 randomized; 106 fully evaluable Patients with solid tumors receiving high-dose cisplatin, cyclophosphamide and carmustine before (autologous) bone marrow transplant	Dronabinol (synthetic THC) capsule	5 mg/m², 2 doses on the last chemotherapy day before carmustine	4 days of high-dose chemotherapy	Comparison: placebo; everyone received an intravenous infusion of prochlorperazine or metoclopramide, plus lorazepam and diphenhydramine. On the last chemotherapy day, when dronabinol was given, there was no significant difference in the number of vomiting episodes among the four groups (median: in the metoclopramide group, 2 with dronabinol and 2 without; in the prochlorperazine group, 2.5 vs. 2). Dronabinol gave no added benefit to this intensive regimen Side effects: Side effects requiring dose reduction or discontinuation (diarrhea, arrhythmia, sleepiness, anxiety, akathisia) were reported for the anti-nausea medicines; no dronabinol-specific rate in the abstract	PMID 8635039, doi:10.1002/1097-0142(19951201)76:11<2330::aid-cncr2820761122>3.0.co, 2-f
Hardy 2023 (MedCan1-CBD) Double-blind, placebo-controlled, dose-escalation RCT (phase 2b)	144 randomized; 121 on day 14 (58 CBD, 63 placebo) Patients with advanced cancer and a high symptom burden receiving palliative care (Australia); not designed for chemotherapy nausea	Synthetic pure CBD oil (100 mg per mL)	From 0.5 mL once a day to 2 mL 3 times a day (50–600 mg/day); median dose chosen by patients 400 mg/day By the patient, according to effect and side effects	28 days	Comparison: placebo; both groups received specialist palliative care. The primary outcome, total symptom distress score, fell by 3.0 points with CBD and 6.2 points with placebo at day 14; no difference (p=0.24); the proportion of responders was also not different (44.8% vs. 58.7%; p=0.13). All symptoms, including nausea (ESAS), decreased over time in both groups, with no difference between groups; no nausea-specific figure in the abstract (full text could not be read) Side effects: Side effects similar between groups; shortness of breath more common with CBD	PMID 36409969, doi:10.1200/JCO.22.01632
Tramèr 2001 Quantitative systematic review of RCTs (Medline, Embase, Cochrane; up to August 2000)	30 randomized comparisons (1975–1997); 1366 patients Cancer patients receiving chemotherapy (2 studies in children, 1 in children and adults)	Oral nabilone (16 studies), oral dronabinol (13) and intramuscular levonantradol (1); smoked cannabis was not tested		Follow-up in the studies 24 hours	Comparison: the anti-nausea medicines of that era (prochlorperazine, metoclopramide, chlorpromazine, thiethylperazine, haloperidol, domperidone, alizapride) and placebo. Cannabinoids were slightly more effective than these medicines: complete control of nausea RR 1.38 (95% CI 1.18–1.62; number needed to treat 6), complete control of vomiting RR 1.28 (1.08–1.51; 8); complete control of vomiting vs. placebo RR 1.84 (1.42–2.38). There was no advantage with chemotherapy of very low or very high emetogenicity. In crossover studies, patients preferred the cannabinoid for their next chemotherapy (RR 2.39) Side effects: More common with cannabinoids: dizziness (49% vs. 17%), dysphoria or depressed mood (13% vs. 0.3%), hallucinations (6% vs. 0%), paranoia (5% vs. 0%), drop in blood pressure (25% vs. 11%); stopping because of side effects 11% vs. 2% (RR 4.67)	PMID 11440936, doi:10.1136/bmj.323.7303.16
Smith 2015 (Cochrane) Systematic review and meta-analysis	23 RCTs (1975–1991) Adult cancer patients receiving chemotherapy	Nabilone (synthetic THC-like cannabinoid), dronabinol (synthetic THC) and similar cannabinoid medicines			Complete absence of nausea and vomiting vs. placebo RR 2.9 (moderate quality); no difference vs. prochlorperazine; no comparison with newer antiemetics (ondansetron, etc.) Side effects: Increased withdrawal because of side effects, dizziness, dysphoria, feeling 'high'	PMID 26561338, doi:10.1002/14651858.CD009464.pub2
Chow 2025 Systematic review and meta-analysis of RCTs (Medline, Embase, CENTRAL; up to March 2024)	26 studies (1975–2024; 23 before 2000; Lane 1990 and Lane 1991 counted separately, although according to Tramèr 2001 they are two publications of the same trial); studies of 8–147 people; 3 in children Cancer patients given cannabinoids to prevent chemotherapy nausea	Nabilone, dronabinol/THC, levonantradol and THC:CBD (mouth spray, capsule)			Comparison: placebo and active anti-nausea medicines (mostly old, single-drug regimens). Overall control of nausea and vomiting was better with cannabinoids than placebo (RR 2.65; 95% CI 1.70–4.12; 8 RCTs); compared with active medicines, there was no difference in any outcome. About half of the studies have concerns about bias. Evidence with today's three- and four-drug regimens (including olanzapine) is very limited; only the THC:CBD capsule trial showed added benefit on top of a current regimen	PMID 39953210, doi:10.1007/s00520-025-09251-w
Kemmner 2026 Systematic review of RCTs (no meta-analysis; 5 databases, June 2024)	32 RCTs; 1889 patients (1495 analyzed) Adult cancer patients receiving chemotherapy	Nabilone, dronabinol, levonantradol and THC:CBD preparations			Comparison: anti-nausea medicines now outdated (22 studies), placebo (9) and today's guideline regimen (1). A cannabinoid benefit was seen in 12 of the 22 studies comparing with older medicines and in 8 of the 9 placebo-controlled studies. The single study testing a cannabinoid in addition to today's guideline regimen (5-HT3 + NK1 antagonist + dexamethasone) showed a benefit, but side effects increased. No study was of high quality; 29 were of low quality. According to the authors, the evidence is insufficient to recommend cannabinoids for chemotherapy nausea	PMID 40797063, doi:10.1007/s11764-025-01876-4
Mücke 2018 Systematic review and meta-analysis (palliative medicine)	9 studies, 1561 participants Palliative care (cancer subgroup)	Cannabinoids			In cancer patients, no difference from placebo in calorie intake, appetite, nausea and vomiting, pain or sleep problems (low/very low quality) Side effects: In cancer, no difference in dizziness/mental health	PMID 29400010, doi:10.1002/jcsm.12273
Phillips 2016 (Cochrane, children) Cochrane systematic review (up to December 2014)	34 RCTs of anti-nausea medicines in children; 4 RCTs with cannabinoids Children and adolescents under 18 receiving chemotherapy	THC (2 studies) and nabilone (2 studies)			Comparison: the anti-nausea medicines of that era (prochlorperazine, metoclopramide, domperidone). Results were conflicting and could not be pooled: in the two Ekert studies THC was superior for nausea and vomiting, in Dalzell 1986 there was less nausea with nabilone, and in the largest study, Chan 1987, there was no difference in complete prevention of vomiting. According to the authors, cannabinoids are probably effective but cause frequent side effects Side effects: With nabilone, dizziness, sleepiness, mood changes; in one child, hallucinations requiring withdrawal from the study; with THC, sleepiness	PMID 26836199, doi:10.1002/14651858.CD007786.pub3, Previous version: Phillips 2010, PMID 20824866
Chhabra 2023 Systematic review and meta-analysis (PROSPERO CRD42020187433)	19 studies (7 RCTs, 8 retrospective chart reviews, 2 open-label studies, 2 case reports); 1927 children with cancer Symptom management in children with cancer	Various cannabinoid products (details not in the abstract)			Cannabinoids were used most often for chemotherapy nausea (11 of 19 studies). According to the authors, there is evidence supporting their use for symptom management, but no solid evidence to establish dose, safety and efficacy in children with cancer. No pooled efficacy figure in the abstract (full text could not be read) Side effects: In controlled studies, sleepiness, dizziness, dry mouth and stopping because of side effects were more common with cannabinoids; no study reported a serious cannabinoid-related side effect	PMID 37635461, doi:10.1002/cncr.34920
NICE 2019 (NG144 guideline) National clinical guideline (United Kingdom; based on a systematic evidence review)	Evidence review A: 28 studies (27 RCTs: 6 parallel, 21 crossover; 1 uncontrolled observational study in children); 27 on chemotherapy nausea, 1 on radiotherapy nausea Persistent (refractory) nausea and vomiting despite optimized standard anti-nausea medicines; adults and children (United Kingdom)	Cannabis-based medicinal products; studies in the evidence review used THC (9), THC + prochlorperazine (1), dronabinol (2), dronabinol + prochlorperazine (1) and nabilone (14)		Evidence review November 2019; guideline November 11, 2019 (last updated March 22, 2021)	Recommendation 1.1.1: nabilone may be considered as add-on treatment in adults aged 18 and over for chemotherapy-induced nausea and vomiting that persists despite optimized standard anti-nausea medicines (NICE uses the word "consider" for recommendations where the benefit is less certain). Recommendation 1.1.2: when considering nabilone, take care with interactions with central nervous system depressants and other centrally acting medicines. Rationale: limited evidence showed complete or partial reduction in nausea and vomiting with nabilone, but most studies were old, of low quality, and compared it with anti-nausea medicines no longer used today (evidence quality low to very low, moderate for some outcomes). No practice recommendation for other cannabis-based products or for children; a research recommendation instead. No recommendation was made for radiotherapy nausea because the only study found (Priestman 1987) provided no efficacy data Side effects: In the evidence review, sleepiness, dizziness and dry mouth were more common with nabilone, especially in children; there were no data on long-term effects such as dependence and mental disorders	PMID 31909928, Evidence review A: persistent nausea and vomiting (NICE, November 2019, PMID 35107906, NBK577077). Guideline: nice.org.uk/guidance/ng144
Polito 2018 (children) Multicenter retrospective chart review (no control group)	110 children Children aged 1–18 (median age 14) given nabilone to prevent acute chemotherapy nausea, 2010–2015	Nabilone (synthetic THC-like cannabinoid); 109 of the 110 children also received a 5-HT3 antagonist	Not in the abstract	Acute phase of one chemotherapy block (up to 24 hours after the last dose)	No comparison. Complete prevention of vomiting in the acute phase in 42 of 83 children (50.6%) with highly emetogenic chemotherapy and in 14 of 26 children (53.8%) with moderately emetogenic chemotherapy. The authors found control with nabilone-containing regimens inadequate and stressed the importance of guideline-consistent preventive treatment Side effects: Nabilone-related side effects in 34% of children (37/110), all grade 2 or milder: sleepiness 20%, dizziness 10%, euphoria 3.6%; stopped in 10 children because of side effects	PMID 30051617, doi:10.1002/pbc.27374
Côté 2016 (radiotherapy) Double-blind, placebo-controlled parallel RCT (single center)	56 randomized (28 nabilone, 28 placebo); 24 people left before the end of the study Patients with squamous cell head and neck cancer (mouth, pharynx, larynx) receiving radiotherapy or chemoradiotherapy (Canada); not selected because of nausea	Nabilone (synthetic THC-like cannabinoid, by mouth) and placebo; in both groups, only metoclopramide was allowed as an extra anti-nausea medicine	Week 1: 0.5 mg at bedtime; week 2: 0.5 mg twice a day; after week 3, at most 2 mg/day (at most 4 tablets a day) Weekly increase; after week 3, the dose was adjusted by the radiation oncologist	Throughout radiotherapy (about 7 weeks) + 4 weeks of follow-up	Comparison: placebo. The primary outcome was quality of life: time to a 15% deterioration was not prolonged by nabilone (p = 0.43). Nausea, measured with a separate weekly questionnaire, was no different from placebo (p = 0.71); no difference in appetite, weight, pain, mood or sleep either. Nausea-specific numbers are not in the abstract (full text could not be read); the study was not designed for nausea Side effects: No difference from placebo in the frequency of sleepiness (p = 0.32), anxiety or dry mouth (as reported in the Ceolin 2024 review; Cochrane 2023 reports the same for sleepiness; full text could not be read)	PMID 26503964, doi:10.1177/0003489415612801, Funding: Canadian public research funds, nabilone and placebo were supplied by the manufacturer, the authors reported no conflicts of interest (as reported in Cochrane 2023)
Priestman 1987 (radiotherapy) Double-blind, randomized crossover RCT (two periods)	40 randomized (1 person did not take the medicine); according to NICE, groups of 20 (nabilone) and 19 (metoclopramide) Patients who developed nausea and vomiting during radiotherapy and had at least 5 sessions remaining (pelvis, abdomen, chest, head and neck and other sites; United Kingdom)	Nabilone (synthetic THC-like cannabinoid, by mouth); comparison: metoclopramide	Nabilone 1 mg twice a day (with a placebo capsule at midday); metoclopramide 10 mg 3 times a day (as reported in the NICE evidence review)	Until the end of radiotherapy, 30 days, or treatment failure (whichever came first)	Comparison: metoclopramide (an anti-nausea medicine of that era; in the MASCC/ESMO 2023 recommendations, 5-HT3 antagonists are the core medicines in high- and moderate-risk radiotherapy). No difference between the two medicines in controlling nausea and vomiting (numbers not in the abstract); according to the authors, the frequency and severity of side effects were significantly greater with nabilone (in NICE's recalculation, side effects in 35 vs. 5 per 100 people, but with a wide confidence interval: RR 6.65; 95% CI 0.90–40.09; very low quality). The NICE evidence review could not extract efficacy data from this study and judged the risk of bias high (randomization and washout period unclear; which period the data came from not stated) Side effects: Dizziness 30% vs. 11%, tiredness 25% vs. 5%, disorientation 20% vs. 5%, dry mouth 15% vs. 5%, euphoria 5% vs. 0% (nabilone vs. metoclopramide; as reported in the NICE evidence review, full text could not be read)	PMID 2822337, doi:10.1016/s0009-9260(87)80151-4, Dose, group size, side-effect percentages and bias assessment: NICE NG144 evidence review A (November 2019), Appendix E and Appendix H.2. Nabilone was supplied by the manufacturer (Eli Lilly)
Ungerleider 1984 (radiotherapy) Comparative clinical study (randomization, blinding and number of participants not stated in the abstract)	Not reported (in the abstract) Cancer patients receiving radiotherapy and experiencing nausea and vomiting (USA)	Oral delta-9-THC; comparison: prochlorperazine	Not reported (in the abstract)	Not reported (in the abstract)	Comparison: prochlorperazine (an anti-nausea medicine of that era). Patients rated the severity of their symptoms, their mood, attention, physical activity and desire for social interaction, and chose the medicine they preferred; according to the authors, THC was "slightly more beneficial" than prochlorperazine. Number of participants, numerical results and statistics are not in the abstract; the full text could not be read Side effects: Not reported (in the abstract; patients recorded side effects)	PMID 6318262, doi:10.1148/radiology.150.2.6318262, Full text could not be read (publisher site returned 403)

Reported side effects

Moderate/severe sedation 18% vs. 7%, dizziness 10% vs. 0%, temporary anxiety 4% vs. 1% (Grimison 2024, THC-containing)
Moderate/severe cannabinoid side effects in 31%: sedation, dizziness, disorientation (Grimison 2020)
Dysphoria, feeling 'high', dizziness (older dronabinol and nabilone studies, Cochrane 2015)
Dizziness 49% vs. 17%, low/depressed mood 13% vs. 0.3%, hallucinations 6% vs. 0%, paranoia 5% vs. 0%, drop in blood pressure 25% vs. 11%; stopping because of side effects 11% vs. 2% (30 older RCTs, Tramèr 2001; nabilone, dronabinol, levonantradol)
Nabilone in children: sleepiness 20%, dizziness 10%, euphoria 3.6%; stopped because of side effects in 10 of 110 children (Polito 2018, observational); hallucinations in one child in the RCTs (Dalzell 1986)
Cannabis hyperemesis syndrome: recurrent episodes of nausea, vomiting and abdominal pain with long-term, frequent cannabis use; goes away when cannabis is stopped (Sorensen 2017, systematic review, PMID 28000146)

Monitoring done in studies

Prescription CBD label: liver tests at baseline and at months 1, 3 and 6, then periodically; stop if ALT/AST >3×ULN + bilirubin >2×ULN, or if transaminases stay >5×ULN
INR in people taking warfarin
Drug blood levels in people taking everolimus/tacrolimus/sirolimus

Who should be careful

People with liver disease / liver metastases / on hepatotoxic treatment: with prescription CBD, ALT >3×ULN in 12–13% (placebo 1%), dose-dependent; in moderate/severe hepatic impairment the label specifies a lower starting dose
People taking warfarin or clopidogrel and those at high risk of bleeding: there is an interaction mechanism (CYP2C9, CYP2C19); no clinical data have been reported showing that CBD directly increases bleeding risk
Before surgery/procedures: ASRA 2023 recommends asking about cannabinoid use and including it in the anesthesia plan; the anesthesia team must be told
People on immunotherapy (checkpoint inhibitors): there is an observational signal and a guideline warning
People taking everolimus, tacrolimus, sirolimus or oral targeted drugs: CBD should not be added without consulting the oncologist/pharmacist
Older adults, people taking many medicines, and those on sedatives/opioids: somnolence, dizziness, risk of falls; with THC-containing products, confusion and psychotomimetic effects
Use for 'treating' tumors: uncontrolled case series are not evidence; ASCO strongly recommends against abandoning standard treatment
Pregnancy/breastfeeding, history of psychiatric illness (with THC-containing products): cancer studies excluded these groups
If nausea and vomiting keep coming back in episodes while using cannabis: cannabis hyperemesis syndrome can occur in people who use cannabis frequently over a long period. Recurrent episodes of severe nausea, vomiting and abdominal pain, with temporary relief from hot showers or baths, are typical; in a systematic review, almost all patients used cannabis at least once a week, and the symptoms went away when cannabis was stopped (Sorensen 2017, PMID 28000146; for diagnosis and treatment, American Gastroenterological Association 2024 clinical practice update). Anyone using cannabis during cancer treatment should talk with their care team about whether the nausea and vomiting may be related to cannabis

Drug interactions

Everolimus: exposure increased ~2.5-fold; label: start everolimus at a lower dose and monitor levels (high, human PK data)
Tacrolimus, sirolimus, digoxin (P-gp substrates): the label states that levels may increase (moderate)
Oral P-gp substrate chemotherapy/targeted drugs (e.g., many tyrosine kinase inhibitors): theoretical; no human data
CYP2C19 substrates and prodrugs (clopidogrel): substrate levels rise, and the active metabolite of prodrugs may decrease; no human data for oncology drugs
Warfarin: case report of INR rise; INR should be monitored
CYP3A4 substrates (taxanes, irinotecan, docetaxel, many TKIs): midazolam unchanged on the label (licensed CBD 750 mg twice daily); a single dose of a CBD-dominant extract (640 mg CBD + 20 mg THC) increased midazolam AUC by 56% (Bansal 2023, PMID 37313955); herbal cannabis tea did not affect irinotecan and docetaxel PK (n=24); nabiximols did not affect temozolomide PK; these results cannot be generalized
Immunotherapy: nivolumab response rate 15.9% vs. 37.5% in cannabis users (mostly THC-containing cannabis) (Taha 2019, PMID 30670598, n=140); in a prospective observational study, time to progression and survival were shorter (Bar-Sela 2020, PMID 32872248, n=102); causality not proven, no data specific to pure CBD
Opioids: in MedCan1, CBD dose was unrelated to opioid use; no opioid-sparing effect shown with THC-containing products; somnolence increases with CNS depressants
Citalopram/escitalopram: citalopram levels rose significantly in 6 patients who added CBD (200–800 mg/day) (Anderson 2021, PMID 34121064)
Valproate and liver-toxic drugs (some chemotherapies, methotrexate): no data on use together with hepatotoxic chemotherapies
Tamoxifen: in one case, endoxifen was found to be low with CBD 40 mg/day (Parihar 2020, PMID 33191836)
No clinical studies reported with direct oral anticoagulants (apixaban, rivaroxaban)

Abbreviations: RCT, randomized controlled trial (a study in which participants are assigned to groups by chance); placebo, an inactive substance; SMD, OR and RR, effect measures used in analyses that pool studies; CYP, liver enzymes that break down medicines.

If you are considering CBD

If your nausea continues, be sure to tell your oncologist; you can ask for your anti-nausea treatment to be reviewed.
If you are considering CBD or another herbal product, talk with your oncologist and pharmacist about how it may interact with your chemotherapy and your other medicines.
This conversation is especially important if you are on immunotherapy, everolimus, warfarin or oral targeted cancer medicines.
If a product is being considered, check its label and its independent certificate of analysis (COA); find out whether it contains THC.

Choose your age group, medicines and situation to prepare a short summary you can take to your doctor. Nothing you enter is sent anywhere.

Open the personal warnings tool Convert drops ↔ mg

Bottom line

The effect of CBD oil on nausea from chemotherapy and radiation therapy (radiotherapy) has not yet been studied. In some patients whose nausea continues despite standard medicines, prescription products containing THC may be considered as an add-on option. Talking openly with your care team about your nausea is the best way to find the support that suits you best.

Frequently asked questions

Does CBD oil work for chemotherapy nausea?

We don't know yet, because there are no controlled studies of pure CBD oil in chemotherapy nausea. In a study looking at general symptoms in advanced cancer, CBD oil did not reduce nausea more than placebo. The positive results in this area come from prescription products containing THC that were compared with an inactive pill (placebo), and they cannot be carried over to CBD oil.

Do THC-containing products help with nausea?

In patients whose nausea continued despite standard anti-nausea medicines, when a capsule containing THC and CBD was added to treatment, the proportion of patients who did not vomit at all and did not need extra anti-nausea medicine rose from 8% to 24%; significant nausea was also less common. In older studies, synthetic THC (dronabinol) and the THC-like medicine nabilone were also more effective than an inactive pill; compared with the anti-nausea medicines of that era, they gave similar or slightly better results. These products can cause sleepiness, dizziness and a feeling of being high, and today they are considered only as an add-on to standard treatment. The UK's national health guideline (NICE, 2019) likewise counts only nabilone as an option that may be considered as add-on treatment in adults for chemotherapy nausea that continues despite standard anti-nausea medicines.

Does CBD interact with my chemotherapy medicines?

It may. CBD can slow the breakdown of some medicines in the body; for example, it was shown to raise everolimus levels about 2.5-fold. For many cancer medicines, there are no human data. So if you are considering CBD, be sure to talk with your oncologist and pharmacist.

Can I stop my anti-nausea medicines and use CBD instead?

In most recent studies, even THC-containing products were tested in addition to standard anti-nausea medicines, not instead of them. When they were given on their own in the 1970s and '80s, they were only slightly better than, or similar to, the medicines of that era, and their side effects were more common. The effect of CBD oil on nausea has never been shown. Make any change to your anti-nausea medicines together with your oncologist.

Can CBD oil be obtained with a prescription for chemotherapy nausea in Turkey?

In Turkey, products derived from cannabis are regulated by the Kenevirden Elde Edilen Ürünlere Dair Yönetmelik (Regulation on Products Derived from Hemp) dated January 31, 2026. These products, including CBD, can be sold only in pharmacies. Those classed as medicines and health products are dispensed with a prescription; the regulation does not state a prescription requirement for supplement products and cosmetics with a THC content of no more than 0.3%. As of October 2026, there is no approved (licensed) CBD medicine in Turkey. If you are thinking of using it, talk with your doctor first.

Does CBD or cannabis help with nausea during radiation therapy (radiotherapy)?

We don't know. There are no studies of pure CBD in radiation-therapy nausea. In a few small studies with THC or THC-like medicines, nabilone was no better than placebo or than an anti-nausea medicine of that era, and it had more side effects than that anti-nausea medicine. THC was found slightly more helpful than another anti-nausea medicine in an old study. The supportive cancer care guideline MASCC/ESMO (2023) and the UK's national guideline NICE (2019) do not recommend cannabinoids for this situation. Talk with your care team about nausea caused by radiation therapy; guidelines recommend anti-nausea medicines for it.

References

Show 45 references

Grimison 2024 (CannabisCINV phase II/III). Double-blind, placebo-controlled RCT (combined analysis). PMID 39151115, doi:10.1200/JCO.23.01836, PMID 32801017, separate row in the table, PMID 30209152
Grimison 2020 (phase II, crossover). Double-blind, placebo-controlled crossover RCT. PMID 32801017, doi:10.1016/j.annonc.2020.07.020, First part of the same phase II/III trial, PMID 39151115
Sukpiriyagul 2023. Double-blind, placebo-controlled crossover RCT. PMID 37608911, doi:10.2147/IJWH.S401938
NCT00553059 (MD Anderson, registry results). Randomized, triple-blind, placebo-controlled parallel study (phase 3). NCT00553059, October 9, 2020, no publication found on PubMed in October 2026)
Duran 2010. Double-blind, placebo-controlled parallel pilot RCT (phase 2). PMID 21039759, doi:10.1111/j.1365-2125.2010.03743.x
Meiri 2007. Double-blind, placebo-controlled parallel RCT (4 groups). PMID 17355735, doi:10.1185/030079907x167525, NCT00642512, 64 people and 2003–2004 period, sponsor Solvay Pharmaceuticals, no results in the registry)
Sallan 1975. Double-blind, placebo-controlled crossover RCT. PMID 1099449, doi:10.1056/NEJM197510162931603
Herman 1979. Two double-blind crossover RCTs (reported together). PMID 375088, doi:10.1056/NEJM197906073002302
Chang 1979. Double-blind, placebo-controlled crossover RCT. PMID 293141, doi:10.7326/0003-4819-91-6-819
Kluin-Neleman 1979. Double-blind, placebo-controlled crossover study (randomization not stated in the abstract). PMID 516362
Frytak 1979. Double-blind, placebo-controlled parallel RCT (3 groups). PMID 517882, doi:10.7326/0003-4819-91-6-825
Ekert 1979 (children). Two double-blind comparative studies; according to the Cochrane review in children, separate randomization for each chemotherapy course (RCT). PMID 231736
Sallan 1980. Double-blind crossover RCT. PMID 6985702, doi:10.1056/NEJM198001173020302
Colls 1980. Double-blind crossover RCT (3 medicines). PMID 6250106, Report of the same study as a letter: Colls 1980, PMID 6104004, Tramèr 2001 counted it twice
Steele 1980. Double-blind crossover RCT. PMID 6250699
Orr 1980. Double-blind, placebo-controlled crossover RCT (3 treatments). PMID 6254456, doi:10.1001/archinte.140.11.1431, Second publication on the same 55 patients: Orr and McKernan 1981, PMID 6271846, Tramèr 2001 counted it twice
Chang 1981. Double-blind, placebo-controlled crossover RCT. PMID 6261926, doi:10.1002/1097-0142(19810401)47:7<1746::aid-cncr2820470704>3.0.co, 2-4
Neidhart 1981. Double-blind crossover RCT (interim report). PMID 6271838, doi:10.1002/j.1552-4604.1981.tb02571.x
Einhorn 1981. Double-blind crossover RCT. PMID 6271844, doi:10.1002/j.1552-4604.1981.tb02576.x
Ungerleider 1982. Double-blind crossover RCT. PMID 6284334, doi:10.1002/1097-0142(19820815)50:4<636::aid-cncr2820500404>3.0.co, 2-4, Patient preference analysis of the same study: Ungerleider 1985, PMID 3010696, 139 patients, preference was determined mainly by reduction in nausea), Tramèr 2001 counted it twice
George 1983. Double-blind crossover RCT. PMID 6311306
Ahmedzai 1983. Double-blind crossover comparative study. PMID 6315040, doi:10.1038/bjc.1983.247
Niiranen 1985. Double-blind crossover RCT. PMID 3002167, doi:10.1097/00000421-198508000-00013
Niederle 1986. Randomized crossover study (blinding not stated in the abstract). PMID 3009962, doi:10.1007/BF01728184
Crawford 1986. Double-blind crossover RCT. PMID 3010011, doi:10.1007/BF02934575
Dalzell 1986 (children). Double-blind crossover RCT. PMID 3013104, doi:10.1136/adc.61.5.502
Pomeroy 1986. Double-blind, randomized, two-cycle comparative study. PMID 3017596, doi:10.1007/BF00256701
Chan 1987 (children). Double-blind crossover RCT. PMID 3035479
Cunningham 1988. Randomized, open-label (unblinded) crossover study. PMID 2838294, doi:10.1016/0277-5379(88)90300-8
McCabe 1988. Randomized comparative crossover study. PMID 2847994, doi:10.1007/BF00175407
Lane 1991. Double-blind, multicenter parallel RCT (3 groups). PMID 1652611, doi:10.1016/0885-3924(91)90026-z, Preliminary report of the same trial: Lane 1990, PMID 2173391, 19 patients, 17 evaluable), Tramèr 2001 counted it twice
Gilbert 1995. Double-blind 2×2 factorial RCT (4 groups). PMID 8635039, doi:10.1002/1097-0142(19951201)76:11<2330::aid-cncr2820761122>3.0.co, 2-f
Hardy 2023 (MedCan1-CBD). Double-blind, placebo-controlled, dose-escalation RCT (phase 2b). PMID 36409969, doi:10.1200/JCO.22.01632
Tramèr 2001. Quantitative systematic review of RCTs (Medline, Embase, Cochrane; up to August 2000). PMID 11440936, doi:10.1136/bmj.323.7303.16
Smith 2015 (Cochrane). Systematic review and meta-analysis. PMID 26561338, doi:10.1002/14651858.CD009464.pub2
Chow 2025. Systematic review and meta-analysis of RCTs (Medline, Embase, CENTRAL; up to March 2024). PMID 39953210, doi:10.1007/s00520-025-09251-w
Kemmner 2026. Systematic review of RCTs (no meta-analysis; 5 databases, June 2024). PMID 40797063, doi:10.1007/s11764-025-01876-4
Mücke 2018. Systematic review and meta-analysis (palliative medicine). PMID 29400010, doi:10.1002/jcsm.12273
Phillips 2016 (Cochrane, children). Cochrane systematic review (up to December 2014). PMID 26836199, doi:10.1002/14651858.CD007786.pub3, Previous version: Phillips 2010, PMID 20824866
Chhabra 2023. Systematic review and meta-analysis (PROSPERO CRD42020187433). PMID 37635461, doi:10.1002/cncr.34920
NICE 2019 (NG144 guideline). National clinical guideline (United Kingdom; based on a systematic evidence review). PMID 31909928, Evidence review A: persistent nausea and vomiting (NICE, November 2019, PMID 35107906, NBK577077). Guideline: nice.org.uk/guidance/ng144
Polito 2018 (children). Multicenter retrospective chart review (no control group). PMID 30051617, doi:10.1002/pbc.27374
Côté 2016 (radiotherapy). Double-blind, placebo-controlled parallel RCT (single center). PMID 26503964, doi:10.1177/0003489415612801, Funding: Canadian public research funds, nabilone and placebo were supplied by the manufacturer, the authors reported no conflicts of interest (as reported in Cochrane 2023)
Priestman 1987 (radiotherapy). Double-blind, randomized crossover RCT (two periods). PMID 2822337, doi:10.1016/s0009-9260(87)80151-4, Dose, group size, side-effect percentages and bias assessment: NICE NG144 evidence review A (November 2019), Appendix E and Appendix H.2. Nabilone was supplied by the manufacturer (Eli Lilly)
Ungerleider 1984 (radiotherapy). Comparative clinical study (randomization, blinding and number of participants not stated in the abstract). PMID 6318262, doi:10.1148/radiology.150.2.6318262, Full text could not be read (publisher site returned 403)

Points that could not be verified from the full text

The current version of the NCCN Antiemesis guideline (2025–2026) could not be read because it requires a login; in the 2017 version, dronabinol and nabilone are an option for breakthrough nausea and vomiting, with no separate category (2A under the NCCN rule)
The full text of MASCC 2022 (Alderman) is paywalled; the statement quoted by ASCO 2024, 'may be considered in refractory chemotherapy nausea in patients not receiving checkpoint inhibitors', could not be verified from MASCC's own text (the MASCC abstract contains only 'insufficient evidence to recommend')
The full text of the 2015 Cochrane review could not be read (its pages on Europe PMC and PMC require human verification); the list of the 23 studies included in the review and which drugs it covers could not be verified from the review itself. The product type in the table row is based on the 'nabilone, dronabinol' information already written in the row and on Tramèr 2001, which covers the same period (studies of nabilone, dronabinol and levonantradol).
Eight older studies published between 1981 and 1985 (most comparing nabilone with placebo or prochlorperazine) have no abstract or no results in their abstract; they were not included in the table because their full texts could not be read. A 109-person placebo-controlled study of dronabinol in pancreatic cancer (NCT03984214) was completed in September 2024; its results have not yet been published.
Of the radiotherapy nausea studies, the full texts of Côté 2016, Priestman 1987, Ungerleider 1984 and Lucraft 1982 could not be read: only their abstracts were read, plus, for Priestman 1987, the dose and side-effect figures reported in the NICE evidence review, and for Côté 2016, what the Cochrane 2023 and Ceolin 2024 reviews reported. The number of participants and the design (whether it was randomized) of Ungerleider 1984 are not in the abstract. A comparative study published in Hebrew (Gez 1983) has no abstract on PubMed; it was not included in the table because it could not be read. Which single RCT the MASCC 2022 review counted for radiotherapy nausea could not be determined from the abstract.

Research history

Here we record what changed on this page, when and why, with dates. The newest change is at the top.

October 31, 2026
The evidence level text now uses the same level name as the top of the page; the level and the result did not change.
October 31, 2026
The last sentence of the page's short summary was rewritten in a calmer, more guiding tone: instead of "Talk to your doctor before you start.", it now says whom you can talk with, and about what, if you are considering CBD. The conclusion and the strength of evidence did not change.
October 28, 2026
October 2026 additional review: sources found for this page during the searches for other topics were read and added to the page. The scope was broadened to include nausea during radiation therapy (radiotherapy), and the title was changed accordingly; PubMed and ClinicalTrials.gov were also searched separately for this section. 4 rows were added to the table: 2 studies with nabilone in radiotherapy nausea (one placebo-controlled, one comparing it with metoclopramide) and 1 older comparative study with THC; and the UK's national guideline NICE (2019; nabilone may be considered as add-on treatment in adults for chemotherapy nausea that continues despite standard medicines). A warning about cannabis hyperemesis syndrome was added. The rule that experimental synthetic cannabinoids do not enter the table as rows (October 28, 2026) was also applied to the 4 older chemotherapy studies on this page with levonantradol, which was never approved: the rows were removed from the table, their findings are mentioned in the evidence summary as background, and the numbers were corrected accordingly. A single-arm study looking at the tolerability of dronabinol in glioma patients, with results only on ClinicalTrials.gov (NCT00314808), was not included in the table because it had no comparison group and tracked nausea only as a secondary outcome. The conclusion and the strength of evidence did not change.
Related studies: NICE 2019 (NG144 guideline), published November 11, 2019 (updated March 22, 2021) (PMID 31909928, Evidence review A: persistent nausea and vomiting (NICE, November 2019, PMID 35107906, NBK577077). Guideline: nice.org.uk/guidance/ng144); Côté 2016 (radiotherapy), published April 2016 (PMID 26503964, doi:10.1177/0003489415612801, Funding: Canadian public research funds, nabilone and placebo were supplied by the manufacturer, the authors reported no conflicts of interest (as reported in Cochrane 2023)); Priestman 1987 (radiotherapy), published September 1987 (PMID 2822337, doi:10.1016/s0009-9260(87)80151-4, Dose, group size, side-effect percentages and bias assessment: NICE NG144 evidence review A (November 2019), Appendix E and Appendix H.2. Nabilone was supplied by the manufacturer (Eli Lilly)); Ungerleider 1984 (radiotherapy), published February 1984 (PMID 6318262, doi:10.1148/radiology.150.2.6318262, Full text could not be read (publisher site returned 403))

Older changes (6)

October 28, 2026
Display fix: internal working file names left in the text were removed; content and evidence did not change.
October 27, 2026
PubMed, Cochrane and ClinicalTrials.gov were systematically searched again in October 2026 (1159 records on PubMed, 39 on ClinicalTrials.gov). 40 studies were added to the table: 30 controlled studies from 1975–1995 with dronabinol, nabilone and levonantradol; two recent studies, one comparing dronabinol with ondansetron and one adding it to palonosetron and dexamethasone (one of them with results only on ClinicalTrials.gov); a pilot study with a mouth spray containing THC and CBD; a recent study with pure CBD in advanced cancer; 5 systematic reviews, including two on children; and a records review of nabilone in children. Corrected: the product type of the Cochrane 2015 row (mixed, because it pooled several types of drugs) and its product description, and the publication date of Sukpiriyagul 2023; the rows now state that the two publications of the CannabisCINV trial are the same trial; the definition of this trial's complete response (no vomiting and no need for extra medicine) was corrected in the text; the statement in the text that “the older studies were not compared with today's anti-nausea medicines” was corrected, and the text now states that dronabinol is THC itself while nabilone is a THC-like medicine. The conclusion and the strength of evidence did not change.
Related studies: NCT00553059 (MD Anderson, registry results), published October 9, 2020 (registry results) (NCT00553059, October 9, 2020, no publication found on PubMed in October 2026)); Duran 2010, published November 2010 (PMID 21039759, doi:10.1111/j.1365-2125.2010.03743.x); Meiri 2007, published March 2007 (PMID 17355735, doi:10.1185/030079907x167525, NCT00642512, 64 people and 2003–2004 period, sponsor Solvay Pharmaceuticals, no results in the registry)); Sallan 1975, published October 16, 1975 (PMID 1099449, doi:10.1056/NEJM197510162931603); Herman 1979, published June 7, 1979 (PMID 375088, doi:10.1056/NEJM197906073002302); Chang 1979, published December 1979 (PMID 293141, doi:10.7326/0003-4819-91-6-819); Kluin-Neleman 1979, published October 1979 (PMID 516362); Frytak 1979, published December 1979 (PMID 517882, doi:10.7326/0003-4819-91-6-825); Ekert 1979 (children), published December 15, 1979 (PMID 231736); Sallan 1980, published January 17, 1980 (PMID 6985702, doi:10.1056/NEJM198001173020302); Colls 1980, published June 25, 1980 (PMID 6250106, Report of the same study as a letter: Colls 1980, PMID 6104004, Tramèr 2001 counted it twice); Steele 1980, published 1980 (PMID 6250699); Orr 1980, published November 1980 (PMID 6254456, doi:10.1001/archinte.140.11.1431, Second publication on the same 55 patients: Orr and McKernan 1981, PMID 6271846, Tramèr 2001 counted it twice); Chang 1981, published April 1, 1981 (PMID 6261926, doi:10.1002/1097-0142(19810401)47:7<1746::aid-cncr2820470704>3.0.co, 2-4); Neidhart 1981, published 1981 (PMID 6271838, doi:10.1002/j.1552-4604.1981.tb02571.x); Einhorn 1981, published 1981 (PMID 6271844, doi:10.1002/j.1552-4604.1981.tb02576.x); Ungerleider 1982, published August 15, 1982 (PMID 6284334, doi:10.1002/1097-0142(19820815)50:4<636::aid-cncr2820500404>3.0.co, 2-4, Patient preference analysis of the same study: Ungerleider 1985, PMID 3010696, 139 patients, preference was determined mainly by reduction in nausea), Tramèr 2001 counted it twice); George 1983, published 1983 (PMID 6311306); Ahmedzai 1983, published November 1983 (PMID 6315040, doi:10.1038/bjc.1983.247); Hutcheon 1983, published August 1983 (PMID 6352278, doi:10.1016/0277-5379(83)90032-9); Heim 1984, published 1984 (PMID 6467496, doi:10.1007/BF00257128); Sheidler 1984, published April 1984 (PMID 6373843, doi:10.1002/j.1552-4604.1984.tb01824.x); Stambaugh 1984, published 1984 (PMID 6392353, doi:10.1002/j.1552-4604.1984.tb02756.x); Niiranen 1985, published August 1985 (PMID 3002167, doi:10.1097/00000421-198508000-00013); Niederle 1986, published April 15, 1986 (PMID 3009962, doi:10.1007/BF01728184); Crawford 1986, published 1986 (PMID 3010011, doi:10.1007/BF02934575); Dalzell 1986 (children), published May 1986 (PMID 3013104, doi:10.1136/adc.61.5.502); Pomeroy 1986, published 1986 (PMID 3017596, doi:10.1007/BF00256701); Chan 1987 (children), published June 1987 (PMID 3035479); Cunningham 1988, published April 1988 (PMID 2838294, doi:10.1016/0277-5379(88)90300-8); McCabe 1988, published September 1988 (PMID 2847994, doi:10.1007/BF00175407); Lane 1991, published August 1991 (PMID 1652611, doi:10.1016/0885-3924(91)90026-z, Preliminary report of the same trial: Lane 1990, PMID 2173391, 19 patients, 17 evaluable), Tramèr 2001 counted it twice); Gilbert 1995, published December 1, 1995 (PMID 8635039, doi:10.1002/1097-0142(19951201)76:11<2330::aid-cncr2820761122>3.0.co, 2-f); Hardy 2023 (MedCan1-CBD), published March 1, 2023 (PMID 36409969, doi:10.1200/JCO.22.01632); Tramèr 2001, published July 7, 2001 (PMID 11440936, doi:10.1136/bmj.323.7303.16); Chow 2025, published February 14, 2025 (PMID 39953210, doi:10.1007/s00520-025-09251-w); Kemmner 2026, published August 2026 (PMID 40797063, doi:10.1007/s11764-025-01876-4); Phillips 2016 (Cochrane, children), published February 2, 2016 (PMID 26836199, doi:10.1002/14651858.CD007786.pub3, Previous version: Phillips 2010, PMID 20824866); Chhabra 2023, published November 15, 2023 (PMID 37635461, doi:10.1002/cncr.34920); Polito 2018 (children), published December 2018 (PMID 30051617, doi:10.1002/pbc.27374)
October 22, 2026
The names of the conclusion labels were simplified: the "Not enough research" label on this page became "Not studied enough". The assessment did not change.
October 21, 2026
PubMed and ClinicalTrials.gov were searched for newly published and previously missed clinical studies. Study added: Sukpiriyagul 2023. The conclusion and the strength of evidence did not change.
Related studies: Sukpiriyagul 2023, published August 16, 2023 (PMID 37608911, doi:10.2147/IJWH.S401938)
October 21, 2026
The full texts of the studies were reread and the information on the page was checked against its sources. Corrected: participant numbers, side-effect and dose information in the study table; drug interaction notes; evidence summary. Points that could not be verified from full texts went down from 4 items to 2. Our evidence assessment for THC-containing products and the recommendation grade of the ASCO 2024 guideline are now written separately. The conclusion and the strength of evidence did not change.
October 19, 2026
Page published. In this first assessment, 4 studies were reviewed.

Evidence changes across all topics