What does the research say?
In a study of 20 people with Crohn’s disease, participants were randomly assigned to two groups and for 8 weeks took either low-dose pure CBD or an inactive medicine (placebo). No difference was seen between the two groups in the score that shows disease activity.
A later study of 56 people with Crohn’s disease used a CBD oil that also contained THC. In those who took this oil, the disease activity score and quality of life improved more than with placebo; but once differences in age, sex and disease duration between the two groups were taken into account, this difference was not statistically confirmed. Examination of the bowel with a camera (endoscopy) and laboratory tests that show inflammation (CRP and calprotectin) did not change either. This suggests that the disease may continue while a person feels better.
In a 10-week study in ulcerative colitis with a CBD-rich plant extract that also contained THC, the rate of the disease going into a calm phase (remission) was similar in the two groups (28% and 26%). Patients found this product harder to tolerate. Two Cochrane reviews from 2018 (3 studies in Crohn’s disease, 2 in ulcerative colitis) also stated that no firm conclusion can be drawn.
In the mild to moderate form of ulcerative colitis limited to the rectum (ulcerative proctitis), a preliminary study without a comparison group was done in 14 patients with an enema containing both CBD and sodium propionate. The disease score improved in many patients; but because there was no placebo group and the product contained another active ingredient besides CBD, this result does not show the effect of CBD.
In two small studies in which THC-rich marijuana was smoked as cigarettes, patients were also randomly assigned to either cannabis or a placebo cigarette with the THC removed. In 21 people with Crohn’s disease who had not responded to other treatments, a clear improvement in symptoms after 8 weeks was more common in the cannabis group (10 of 11 people, versus 4 of 10 with placebo), but the difference in the disease calming down completely (remission) was not statistically confirmed. In 32 patients with mild to moderate ulcerative colitis, the symptom score and quality of life improved more in the cannabis group; however, there was no difference between the two groups in examination of the bowel with a camera or in inflammation tests. Because the effect of THC can be felt, participants may have noticed which group they were in; the authors also pointed out the harms of the cigarette form.
Newer reviews that bring these small studies together paint a similar picture: cannabis products did not affect the disease going into a calm phase (remission) or markers of inflammation clearly differently from an inactive medicine; some symptoms and quality of life improved. A review published in 2026 that focused on THC-containing products stated that, with today’s evidence, it cannot be decided whether there is a benefit, and that the studies have a high risk of bias. The 2019 position statement of the Canadian Association of Gastroenterology also says that the evidence is insufficient to recommend cannabis as a treatment that reduces inflammation and that it should not be used in place of approved treatments; this statement is expert opinion without a formal grading of evidence.
In real-world studies that followed patients using cannabis (116 patients in the UK, 149 in Israel), an improvement in quality of life was reported; in the Israeli series, a small increase in appetite was seen that was not statistically confirmed, and weight did not change. However, these studies had no comparison group, and in the Israeli series half of the patients dropped out of follow-up by month 6. The results of large registry studies comparing cannabis users with non-users do not agree with each other: among hospitalized patients in the US, some complications were less common and others more common, and two analyses of the same database gave opposite results for fistula and abscess; in a large study based on health records, emergency visits, hospital admissions and steroid use were more common in cannabis users, with no difference in surgery or death; in Canada, use for more than 6 months was linked to needing surgery in Crohn’s disease. These studies do not show cause and effect; people with more severe disease may be more likely to try cannabis.
Strength of evidence: ●●○○ Weak evidence. Finding: No effect found. What does this mean?
Ongoing research on this topic
Trials testing CBD for this topic on ClinicalTrials.gov: 1 under way (1 recruiting). A trial being under way does not show that CBD works.
- NCT06842316: Observational study, recruiting, target 100 participants
Possible side effects and drug interactions
The abstract of the low-dose pure CBD study says no side effects were seen; the Cochrane review, however, recorded the disease getting worse in one patient in each group in this study as a serious event. In the ulcerative colitis study, patients taking the product that also contained THC found it harder to tolerate, and some side effects were attributed to THC; side effects were generally more common in the groups taking cannabis products. In the marijuana cigarette studies, dizziness, confusion and cough were reported more often; in the ulcerative colitis study, these differences were not statistically confirmed and the side effects did not lead anyone to stop treatment. In a real-world study in Israel, more than half (63%) of the patients assessed at month 3 reported a side effect. In healthy volunteers, CBD increased the risk of diarrhea; this should be kept in mind in these conditions, where diarrhea can already occur.
These studies did not look at drug interactions separately. Because CBD can slow the breakdown of some medicines in the body, patients who take medicines regularly should keep this in mind.
To check interactions with the medicines you take: CBD drug interaction checker.
How was CBD used in studies?
In the pure CBD study in Crohn’s disease, 10 mg of CBD (study dose; not a personal recommendation) was taken by mouth twice a day for 8 weeks. With the oil that also contained THC (160 mg CBD and 40 mg THC per milliliter), patients started with one drop twice a day and increased as needed up to at most 20 drops twice a day; according to secondary sources, one drop contained about 8 mg CBD and 2 mg THC, and the median amount used in the cannabis group was reported as 10 drops (0.5 mL) (whether this was daily or per dose is not clear in the available source). In the ulcerative colitis study with CBD-rich capsules that also contained THC, patients started with 50 mg CBD twice a day and, if tolerated, increased to 250 mg twice a day. In the marijuana cigarette studies, patients smoked two cigarettes a day (in Crohn’s disease, 115 mg THC per cigarette; in ulcerative colitis, about 80 mg THC in a 0.5 g cigarette); in ulcerative colitis, they started with half a cigarette on the first day. The enema in ulcerative proctitis delivered 60 mg synthetic CBD and 70 mg sodium propionate once a day.
Study details (for health professionals)
Low-dose pure CBD was ineffective in Crohn’s disease. A CBD oil containing THC eased symptoms (in the analysis adjusted for differences in age, sex and disease duration, the difference was not confirmed), but endoscopy, CRP and calprotectin, which show inflammation in the bowel, did not change. In ulcerative colitis, the primary outcome was negative with a CBD-rich extract that also contained THC. In two small RCTs with THC-rich marijuana cigarettes (21 people in Crohn’s disease, 32 in ulcerative colitis), symptoms and quality of life improved compared with placebo; but in Crohn’s disease the difference in complete remission was not significant, and in ulcerative colitis there was no difference from placebo in endoscopy, CRP or calprotectin, and blinding was weak. Reviews assessing the RCTs (Cochrane 2018, Doeve 2021, Kang 2025, Jugl 2026) found no significant difference from placebo in remission, endoscopy or inflammation markers; some report improvement in symptom scores and quality of life, but the certainty of evidence ranges from very low to moderate, and all rest on the same small studies. In a 14-patient uncontrolled pilot study with a CBD + sodium propionate enema in ulcerative proctitis, the Mayo score improved; there was no control group, and the product contains another active ingredient besides CBD. A patient may 'feel well' while the disease progresses; CBD should not replace standard treatment (biologic medicines, steroids, etc.). The 2019 position statement of the Canadian Association of Gastroenterology also states that, based on the evidence at the time, cannabis did not appear to change the course of these conditions for better or worse, that the evidence is insufficient to recommend it as a treatment that reduces inflammation, and that it should not be used in place of approved treatment (expert opinion without a formal grading of evidence; 3 of the 7 authors have ties to cannabis or cannabinoid companies). The results of observational studies comparing patients who use cannabis with those who do not are conflicting: in Canada, use for more than 6 months was linked to surgery in Crohn’s disease; in a large US study based on health records, emergency visits, hospital admissions, and steroid and opioid use were more common in cannabis users, but there was no difference in surgery or death; in coded data of hospitalized patients, some complications were less common and others more common. People with more severe disease using cannabis more often may explain these links; these studies do not show cause and effect. October 2026 search (PubMed, Cochrane, ClinicalTrials.gov, Europe PMC): 5 randomized controlled trials with cannabinoids on this topic (all small: 20–60 people, 8–10 weeks) and 9 systematic reviews or meta-analyses, including two Cochrane reviews, were found; all of the controlled trials, the most comprehensive and up-to-date reviews, the 2019 position statement of the Canadian Association of Gastroenterology (added in the October 28, 2026 completion round) and the main observational studies are in the table below. There are no controlled studies in children and adolescents; a 15-person RCT with pure CBD in steroid-dependent Crohn’s disease was completed in 2022, but its results have not been published.
Evidence assessment: Weak (a single small RCT with pure CBD, low dose)
CBD alone
The only RCT with pure, low-dose CBD (10 mg twice a day) was negative in Crohn’s disease. There is no published study comparing pure CBD with placebo in ulcerative colitis; in a 14-person uncontrolled study in mild to moderate ulcerative colitis limited to the rectum (proctitis) with an enema containing both synthetic CBD and sodium propionate, which is not a cannabinoid, the disease score improved, but because there was no placebo group and the product contained a second active ingredient, the effect of CBD cannot be shown on its own. A 15-person RCT with synthetic pure CBD in steroid-dependent Crohn’s patients was completed in 2022, but its results have been neither published nor posted to the registry (October 2026).
Products containing THC
There are 4 small RCTs with THC-containing products (21–60 people, 8–10 weeks). In Crohn’s disease, with a CBD/THC oil the disease activity score and quality of life improved more than with placebo, but once differences in age, sex and disease duration between the two groups were taken into account, this difference was not statistically confirmed; objective measures of inflammation (endoscopy, CRP, calprotectin) did not change either. In Crohn’s disease, clinical response was more common with THC-rich marijuana cigarettes, but the difference in the primary outcome, complete remission, was not significant. In ulcerative colitis, the primary outcome (remission) was negative with a CBD-rich extract that also contained THC; THC-rich marijuana cigarettes improved the symptom score, but there was no difference from placebo on endoscopy. Because the effect of THC can be felt, blinding was weak. Reviews find no difference in remission or inflammation; the certainty of evidence ranges from very low to moderate.
Evidence: Weak (4 small RCTs; signs of improvement in symptoms, no difference shown in inflammation)
Dose range in studies
Pure CBD 10 mg twice a day (Crohn’s disease); 100–500 mg/day CBD in a THC-containing extract (ulcerative colitis); in the CBD/THC oil in Crohn’s disease, from 2 × 1 drop a day up to at most 2 × 20 drops (according to secondary sources, about 8 mg CBD + 2 mg THC per drop); THC-rich marijuana cigarettes, 2 a day (Crohn’s disease and ulcerative colitis); in ulcerative proctitis, 60 mg synthetic CBD in 1 enema a day
Starting dose and titration
Drop-by-drop increase with the CBD/THC oil (at most 40 drops a day); with the CBD-rich capsules, from 2 × 50 mg to 2 × 250 mg if tolerated; in the cigarette study in ulcerative colitis, from half a cigarette to 2 × 0.5 g a day
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.
| Study | Participants | Product | Dose and titration | Duration | Result | Source |
|---|---|---|---|---|---|---|
| Naftali 2017 Placebo-controlled RCT | 20 randomized; 19 completed Crohn’s disease | Pure CBD (by mouth) | 10 mg × 2/day | 8 weeks | No difference from placebo in disease activity (CDAI): 220 ± 122 vs 216 ± 121 at week 8 (337 and 308 at baseline). According to Cochrane, remission 4/10 vs 3/9 (RR 1.20; 95% CI 0.36–3.97; very low certainty) Side effects: No side effects observed according to the abstract; according to the Cochrane review, worsening of the disease was recorded as a serious event in 1 person in each group (1/10 vs 1/9) | PMID 28349233, doi:10.1007/s10620-017-4540-z, NCT01037322, in the registry the arm description gives the dose as 2 × 5 mg sublingual drops a day and the inclusion criteria give 10 mg, the publication gives 2 × 10 mg a day) |
| Naftali 2021 (Crohn’s) Double-blind, placebo-controlled RCT | 56 randomized (30 cannabis oil, 26 placebo) Crohn’s disease | CBD/THC oil 160/40 mg/mL (contains THC) | Started at 2 × 1 drop a day and increased based on benefit or side effects; upper limit 2 × 20 drops a day. According to secondary sources, one drop contained 8 mg CBD + 2 mg THC (at most 320 mg CBD + 80 mg THC a day); the median amount used in the cannabis group was 10 drops (0.5 mL; about 80 mg CBD + 20 mg THC, IQR 52–108 mg CBD), not stated whether per day or per dose Drop-by-drop increase based on benefit or side effects; upper limit 40 drops a day | 8 weeks | CDAI fell from 282 to 166 with cannabis oil and from 264 to 237 with placebo (median; between-group p = 0.038); quality of life 91 vs 75 (p = 0.004). However, the groups differed in age, sex and disease duration (median age 28 vs 33); in the analysis adjusted for these, neither difference was significant (CDAI p = 0.072; quality of life p = 0.143), and the target of a 30-point improvement in quality of life was not met. Endoscopy score (SES-CD 10 to 7 and 11 to 8; p = 0.75), CRP and calprotectin did not change. The product was supplied by the manufacturing company; one of the authors is a company employee. The adjusted analysis and detailed numbers come from the data supplement of Jugl 2026, not from the full text of the main publication Side effects: Not in the abstract. According to the main publication's side effect table (from the Jugl 2026 data supplement): blurred vision, confusion, forgetfulness and dizziness were more common with cannabis oil (e.g., confusion 4/16 vs 0/20, forgetfulness 6/14 vs 1/19, dizziness 5/15 vs 2/18); none of the differences was significant; the denominators vary by question | PMID 33858011, doi:10.1093/ecco-jcc/jjab069, Secondary analysis (endocannabinoid levels): Tartakover Matalon 2021, PMID 34531823, amount used, PMID 42231518, NCT01826188, 50 people, 2013–2018, registered concentration 50 mg/mL CBD + 5 mg/mL THC, no results in the registry) may be this study's registration, the link could not be verified |
| Irving 2018 Multicenter pilot RCT | 60 randomized (29 CBD-rich extract / 31 placebo); 16 and 23 completed Ulcerative colitis | CBD-rich botanical extract, capsule (THC up to 4.7%) | Started at 50 mg × 2/day, increased to 250 mg × 2/day if tolerated (100–500 mg/day) Dose increased over the first 2 weeks, then continued at the highest tolerated dose | 10 weeks | Primary outcome (remission) negative: 28% vs 26%; in per-protocol patients, some subjective measures favored CBD. Sponsored by the company that makes the product Side effects: Side effects in 100% of the CBD group (29/29) and 77% of the placebo group (24/31), mostly mild to moderate. Withdrawal due to side effects 10/29 vs 5/31. Serious side effects 0 with CBD, 4 with placebo. Some of the side effects were attributed to THC | PMID 29538683, doi:10.1093/ibd/izy002, NCT01562314, dose and side effects from the registry), THC content from the Cochrane summary (Kafil 2018, PMID 30406638 |
| Naftali 2026 Open-label, single-arm pilot study | 14 (9 completed) Mild-to-moderate ulcerative proctitis not responding to at least 3 months of mesalamine | Synthetic CBD + sodium propionate enema (rectal); sodium propionate is not a cannabinoid but a separate active ingredient | 1 enema a day (50 mL; 60 mg synthetic CBD + 70 mg sodium propionate) | 12 weeks | Reduction of ≥3 in Mayo score: 50% by intention to treat, 77% among those who completed the protocol; tissue (histologic) healing not significant; no control group. Funded by the manufacturing company; one of the authors is a company employee Side effects: Mild side effects; 1 serious event unrelated to treatment | PMID 42578019, doi:10.1159/000552842, The registration cited in the publication, NCT06353828, was opened after the study ended (March 2024) and describes a 45-person randomized, placebo-controlled phase 2a trial, it does not match this open-label pilot (no results in the registry) |
| Kafil 2020 (Cochrane summary) Journal summary of two Cochrane systematic reviews (5 RCTs, 185 people) | 185 Crohn’s disease and ulcerative colitis | Marijuana cigarettes, cannabis oil, CBD extract | No firm conclusions can be drawn; certainty of evidence ranges from 'very low' to 'moderate'. The search was run in 2018: the marijuana cigarette study in ulcerative colitis (Naftali 2021, ulcerative colitis) existed only as a conference abstract at the time; a 50-person study of CBD/THC oil in Crohn’s disease was also included using unpublished data (most likely the one later published as Naftali 2021, Crohn’s) Side effects: Side effects more common in the cannabis groups | PMID 31613959, doi:10.1093/ibd/izz233, Cochrane reviews: Kafil 2018, Crohn’s (CD012853, PMID 30407616, PMID 30406638 | ||
| Naftali 2013 Placebo-controlled RCT (triple-blind per the registry; Cochrane rated the blinding as high risk of bias) | 21 randomized (11 cannabis, 10 placebo) Active Crohn’s disease (CDAI > 200) not responding to steroids, immunomodulators or anti-TNF therapy, Israel | THC-rich marijuana cigarette (115 mg THC per cigarette); placebo: cannabis flower with the THC removed | 2 cigarettes a day | 8 weeks + 2 weeks of follow-up | The primary outcome (complete remission, CDAI < 150) was not significant: 5/11 vs 1/10 (p = 0.43; Cochrane: RR 4.55; 95% CI 0.63–32.56; very low certainty). Clinical response (a drop of more than 100 points in CDAI) 10/11 vs 4/10 (p = 0.028); in the cannabis group, 3 patients stopped steroids, and appetite and sleep improved. The abstract gives no endoscopy or inflammatory marker results. Cochrane: the cannabis group was older; blinding at high risk of bias Side effects: The abstract states there were no significant side effects; according to Cochrane, side effects were more common in the cannabis group (RR 4.09; 95% CI 1.15–14.57; very low certainty): sleepiness, nausea, difficulty concentrating, forgetfulness, confusion, dizziness; all mild | PMID 23648372, doi:10.1016/j.cgh.2013.04.034, NCT01040910, no results in the registry), PMID 24262941, PMID 24418092 |
| Naftali 2021 (ulcerative colitis) Double-blind, placebo-controlled RCT (single center) | 32 randomized (17 cannabis, 15 placebo); all completed Adults with mild-to-moderate active ulcerative colitis (excluding disease limited to the rectum) who had not used cannabis before, Israel | THC-rich marijuana cigarette (0.5 g; 16% THC on analysis, about 80 mg THC, 0.1% CBD); placebo: marijuana with the THC removed | 2 × 0.5 g cigarettes a day Half a cigarette (0.25 g) on the first day, increased in 0.25 g steps to 2 × 0.5 g a day | 8 weeks + 2 weeks of follow-up | The primary outcome, the Lichtiger symptom score, fell from 10.9 to 5 with cannabis and from 11 to 8 with placebo (between-group p = 0.006; 0.001 in the abstract). Quality of life rose from 77 to 98 with cannabis and did not change with placebo (p = 0.026). No between-group difference in the endoscopic Mayo score (p = 0.374); CRP and calprotectin did not change. The cannabis was supplied by the producing company, and one of the authors is a company employee; according to the authors, at least 3 placebo patients thought they had received cannabis Side effects: Cough 41% vs 20%, dizziness 35% vs 6%, confusion 29% vs 6%, difficulty stopping 29% vs 12%, behavior change 23% vs 0%; in these small groups none of these differences was statistically significant (p ≥ 0.27); none led to stopping treatment | PMID 33571293, doi:10.1371/journal.pone.0246871, NCT01040910, last updated December 2011, the design and results of this 32-person study are not in the registry), secondary analysis: Tartakover Matalon 2021, PMID 34531823 |
| Doeve 2021 Systematic review and meta-analysis (5 RCTs + 15 non-randomized studies) | 146 randomized patients in the remission meta-analysis Crohn’s disease and ulcerative colitis (all ages searched; all RCTs in adults) | Cannabis and cannabinoids (cigarettes, oil, capsules) | No significant difference from placebo in remission (RR 1.56; 95% CI 0.99–2.46); no effect on inflammatory markers. Patient-reported symptoms such as abdominal pain, general well-being, nausea, diarrhea and appetite, and quality of life, improved. In observational studies, hospital stays were shorter and the need for parenteral (IV) nutrition was lower, with no difference in other complications. Search through August 2019; moderate risk of bias Side effects: Not reported (in the abstract) | PMID 32675631, doi:10.1097/MCG.0000000000001393 | ||
| Kang 2025 Meta-analysis of RCTs (8 studies: 4 Crohn’s disease, 3 ulcerative colitis, 1 both) | Not reported (in the abstract) Crohn’s disease and ulcerative colitis | Cannabinoids (CBD, THC-containing products) | Clinical disease activity decreased in Crohn’s disease (pooled effect −0.91; 95% CI −1.54 to −0.28; high heterogeneity, I² 72%); not significant in ulcerative colitis (−2.13; −4.80 to 0.55; I² 90%). Quality of life improved in both diseases; no difference in endoscopic activity or inflammatory markers. The abstract counts 8 studies, whereas the known number of separate RCTs on this topic is 5 (3 in Crohn’s disease, 2 in ulcerative colitis): secondary analyses of the same patients or conference abstracts may have been counted separately. The effect measures in the abstract are labeled 'risk ratio' but have negative values. Full text could not be read; the list of included studies could not be verified Side effects: Not reported (in the abstract) | PMID 39197096, doi:10.1093/ibd/izae158 | ||
| Jugl 2026 Systematic review (GRADE; 4 RCTs + 4 observational studies; no meta-analysis) | 4 RCTs (21–60 people; the pure CBD study without THC was out of scope) + 4 observational studies (Desai 2019, the two Mbachi 2019 analyses, Coates 2022) Crohn’s disease and ulcerative colitis (adults) | THC-containing cannabis products (marijuana cigarette, CBD/THC oil, CBD-rich capsule that also contains THC) | No difference from placebo in remission (3 RCTs, 150 people), endoscopic score, IBDQ, nausea or weight; mixed results for disease activity score, quality of life and pain; bloating and appetite improved in one study only (low quality of evidence). For the Crohn’s oil study, the authors' analysis adjusted for age, sex and disease duration was used. All RCTs had a high risk of bias; the observational studies were not included in the evidence assessment because of serious or critical risk of bias. Conclusion: the benefit of THC-containing products is uncertain. Search February 2023; repeated for RCTs through February 2026, with no new RCTs found. Funded by the US Food and Drug Administration (FDA) Side effects: Limited safety information in the RCTs | PMID 42231518, doi:10.1186/s42238-026-00456-2, PROSPERO CRD42023411910 | ||
| CAG 2019 (Andrews) Professional society position statement (Canadian Association of Gastroenterology; non-comprehensive literature review and expert opinion; no formal evidence grading of the statements) | Digestive and liver diseases; this row reports the inflammatory bowel disease (Crohn’s, ulcerative colitis) section and the general statements | Cannabis and cannabinoids | Inflammatory bowel disease statement: based on the evidence at the time, cannabis does not appear to change the course of the disease for better or worse. Commentary: evidence that cannabis reduces objective measures of inflammation is largely lacking and limited to studies too small to show a clinically meaningful difference; the evidence is insufficient to recommend cannabis as a treatment that reduces inflammation; large RCTs with standardized products, objective outcomes and long follow-up are needed. General statement: cannabis should not be used in place of approved treatment for any digestive or liver disease when approved treatment is available and has not yet been tried; use alongside approved treatment for symptoms only may be reasonable if the risk of harm appears low. The document notes that three Israeli studies were supported by a cannabis-producing company, and it reports the marijuana cigarette study in ulcerative colitis from what was then only a 28-patient conference abstract (the abstract had reported endoscopic improvement; in the same team's full 32-patient paper published in 2021, Naftali 2021, endoscopy showed no difference from placebo). The statement was written in 2018; it does not cover later RCTs and reviews | PMID 31294362, doi:10.1093/jcag/gwy064, PMC6507278 (full text read). According to the conflict-of-interest statement, 3 of the 7 authors have ties to companies that make cannabis or cannabinoid products (advisory board and executive role, research support and donated product, speaker fees and advisory board). The same document also appears in the irritable bowel and stomach table | ||
| Gupta 2024 Patient registry analysis (no control group) | 116 Patients with Crohn’s disease and ulcerative colitis prescribed cannabis-based medicines (UK Medical Cannabis Registry; 81% male) | Cannabis-based medicinal products (containing THC and CBD; product details not given in the abstract) | Not reported (in the abstract) | 18 months | IBD-specific quality of life (SIBDQ), anxiety (GAD-7), sleep and general quality of life improved at month 18 compared with baseline (p < 0.001); 26% (30 patients) reached a clinically meaningful improvement on the SIBDQ, more often in those with severe anxiety at baseline and those taking above-median THC. No control group; the authors state that cause and effect cannot be inferred Side effects: 155 side effects in total in 20 patients (17%) | PMID 39689344, doi:10.1080/17474124.2024.2443574, Earlier analysis of the same registry: Dalavaye 2023, PMID 36562418, 3 months, overlapping sample) |
| Fliss Isakov 2023 Prospective case series (no control group) | 149 started; 88 assessed at month 3, 74 at month 6 Patients with Crohn’s disease (72%), ulcerative colitis and pouchitis starting medical cannabis (Israel, single center) | Medical cannabis flower, oil or both (contains THC and CBD) | Mean prescribed THC 1.7 ± 1.3 g/month, CBD 2.4 ± 0.9 g/month | 6 months | At month 3, a non-significant increase in appetite score (p = 0.08); energy and nutrient intake and body mass index did not change. Among the 50 patients started on cannabis to increase appetite, appetite rose clearly in one third (17), but calorie intake and weight did not change; in this group, those whose appetite did not increase had a lower body mass index at month 6. Half of the patients dropped out of follow-up by month 6; no control group. Disease activity was not the subject of this publication Side effects: At month 3, 63% of patients (55/88) reported a side effect; 31% stopped treatment or reduced the dose | PMID 38201908, doi:10.3390/nu16010078 |
| Storr 2014 Cross-sectional survey (comparison of patients who use and do not use cannabis) | 313 Consecutive patients with Crohn’s disease and ulcerative colitis (Calgary, Canada) | Self-directed cannabis use (96% by inhalation) | 17.6% of patients had used cannabis for bowel symptoms; they reported improvement in abdominal pain, cramping, joint pain and diarrhea. In Crohn’s disease, use for more than 6 months was associated with needing surgery (OR 5.03; 95% CI 1.45–17.46; adjusted for demographic factors, smoking, disease duration and biologic drugs); there was no association with hospitalization in the past year. Survey-based and retrospective; no adjustment for disease severity (according to the abstract), and patients with more severe disease may use cannabis longer (reverse causation); does not show cause and effect. The number of Crohn’s patients using cannabis is not given in the abstract Side effects: Side effects were commonly reported (no numbers in the abstract) | PMID 24407485, doi:10.1097/01.MIB.0000440982.79036.d6 | ||
| Glickman 2024 Retrospective cohort, propensity score–matched (TriNetX health records network, US) | Not reported (in the abstract) Crohn’s disease and ulcerative colitis; cannabis users versus non-users | Cannabis use in health records (definition and product not given in the abstract) | Cannabis users had more steroid use (RR 1.10; 95% CI 1.02–1.17), emergency department visits (RR 2.14; 2.03–2.26), hospitalizations (RR 1.93; 1.78–2.08) and opioid use (RR 1.35; 1.14–1.60); there was no difference in disease-related surgery or death. Results were similar when Crohn’s disease and ulcerative colitis were looked at separately; the increase in steroid and opioid use was seen only in Crohn’s disease. How cannabis use was identified is not stated in the abstract. Observational; the authors write that it is unclear whether these risks stem from disease severity or from other factors; does not show cause and effect | PMID 37580878, doi:10.1093/ibd/izad151, PMID 37580879, PMID 37738592, PMID 37738640, PMID 39241176, PMID 39361966 | ||
| Desai 2019 Retrospective, propensity score–matched analysis (US National Inpatient Sample, 2010–2014); two Mbachi 2019 analyses using overlapping years of the same database are also covered in this row | 6,002 Crohn’s admissions (2,999 cannabis users) and 1,481 ulcerative colitis admissions (742 cannabis users); Mbachi 2019: 615 Crohn’s and 298 ulcerative colitis users, with matched non-users Hospitalized patients with Crohn’s disease and ulcerative colitis; those with versus without a diagnosis code for cannabis use or dependence | Recreational cannabis use (by diagnosis codes) | In Crohn’s disease, cannabis users had less colorectal cancer (0.3% vs 1.2%), parenteral (IV) nutrition and anemia; fistula or intra-abdominal abscess (8.6% vs 5.9%), lower gastrointestinal bleeding and fluid loss were more common. In ulcerative colitis, fluid and electrolyte disorders were more common. In both diseases, hospital stays were shorter. The Mbachi 2019 analyses of the same database, which excluded people using other substances, found the opposite for fistula or abscess in Crohn’s disease: less common (11.5% vs 15.9%); colon surgery was less common in Crohn’s disease (3.7% vs 7.5%) and in ulcerative colitis (4.4% vs 9.7%). That the same data give opposite results with different selections shows how fragile these analyses are. Cannabis use was identified by diagnosis codes (abuse or dependence); cross-sectional; disease severity and medications could not be taken into account; Jugl 2026 rated the risk of bias of the three analyses as critical; does not show cause and effect | PMID 31355219, doi:10.21037/atm.2019.04.63, Separate analyses of the same database with overlapping years: Mbachi 2019, Crohn’s (Dig Dis Sci, PMID 30825109, 2012–2014, PMID 31388856, PMID 31393356, PMC6708902, 2010–2014, PMID 31464963 |
Reported side effects
- In healthy volunteers, CBD increased the risk of diarrhea (RR 5.85); a non-significant trend toward more belly pain and headache (Sawaira 2026, PMID 41789242)
- Psychiatric and nervous system side effects more common with THC-containing products (Filippini 2022, PMID 35510826); the odds of side effects increased with any cannabinoid (OR 1.75; Wilson 2026, PMID 41856154)
- With THC-rich marijuana cigarettes, cough 41%, dizziness 35%, confusion 29% (20%, 6%, 6% with placebo; in the 32-person study, the differences were not statistically significant; Naftali 2021, ulcerative colitis); in Crohn’s disease, side effects more common with THC cigarettes than with placebo (RR 4.09; 95% CI 1.15–14.57; very low certainty; Cochrane, Kafil 2018)
- In a real-world series in Israel, 63% of patients assessed at month 3 reported a side effect and 31% stopped treatment or reduced the dose (Fliss Isakov 2023); in a UK registry, 17% of patients reported a side effect over 18 months (Gupta 2024)
Monitoring done in studies
- Even when symptoms improve, inflammation checks (calprotectin, CRP, endoscopy) continue according to the doctor’s plan; in the studies, these measurements did not change differently from placebo while symptoms improved (Naftali 2021, Crohn’s disease and ulcerative colitis)
Who should be careful
- High doses and over-the-counter doses cannot be compared: in low-dose studies (≤175 mg/day), plasma levels were 5–100 times lower than with a 20 mg/kg Epidiolex dose (Warren 2026, PMID 42473010)
- Anyone who takes medicines long-term should consult a doctor before starting; the studies on this page did not systematically assess interactions
- CBD should not replace the standard treatment of inflammatory bowel disease
- Even when symptoms improve, there is no objective evidence that inflammation goes down
- In observational studies, cannabis use was linked to surgery in Crohn’s disease (Storr 2014) and to emergency visits, hospital admissions and steroid use (Glickman 2024); in other registry studies, some complications were less common. People with severe disease using cannabis more often may explain these links; cause and effect has not been shown
Drug interactions
- The studies on this page did not systematically assess drug interactions; details are in the site's drug interactions section
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
- Do not stop or cut back your biologic medicine, steroid or other treatments on your own; CBD should not replace standard treatment.
- Even if you feel better, keep up the checkups your doctor recommends; symptoms improving may not mean the inflammation has gone down.
- If you take medicines regularly, review CBD together with your doctor or pharmacist.
- Check the product’s label and 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.
Bottom line
Controlled studies of CBD and cannabis in Crohn’s disease and ulcerative colitis are few and small; the results are limited. Products that also contain THC may help some patients feel better, but it has not been shown that inflammation in the bowel goes down. That is why continuing your main treatment and going to regular checkups matters so much.
Frequently asked questions
Does CBD oil work for Crohn’s disease and ulcerative colitis?
For now, there is no solid evidence that it does. Low-dose pure CBD gave no different result from an inactive medicine (placebo) in Crohn’s disease. An oil that also contained THC and THC-rich marijuana smoked as cigarettes eased some symptoms, but tests that show inflammation gave no different result from the inactive medicine. In ulcerative colitis, the main outcome was negative with a CBD-rich extract that also contained THC; in a small study with marijuana cigarettes, symptoms improved but no difference was seen in inflammation in the bowel.
If I feel better, has the inflammation gone down?
Not always. In two small studies, one with a CBD oil that also contained THC in Crohn’s disease and one with marijuana cigarettes in ulcerative colitis, patients felt better, but endoscopy and inflammation tests gave no different result from an inactive medicine (placebo). The checkups your doctor orders show how the disease is progressing.
Can CBD replace a biologic medicine or a steroid?
No. There is no evidence that CBD can replace the standard treatment of these conditions. Do not stop or cut back your medicines on your own.
Does CBD cause diarrhea?
In studies of healthy volunteers, CBD increased the risk of diarrhea. In people with bowel disease, this side effect may matter even more; tell your doctor about new or worsening bowel symptoms.
Can CBD oil be obtained with a prescription for Crohn’s disease and ulcerative colitis in Turkey?
In Turkey, products obtained 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 classified as medicines or health products are dispensed with a prescription; for supplement products and cosmetics with a THC content of at most 0.3%, the regulation does not state a prescription requirement. 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.
References
Show 16 references
- Naftali 2017. Placebo-controlled RCT. PMID 28349233, doi:10.1007/s10620-017-4540-z, NCT01037322, in the registry the arm description gives the dose as 2 × 5 mg sublingual drops a day and the inclusion criteria give 10 mg, the publication gives 2 × 10 mg a day)
- Naftali 2021 (Crohn’s). Double-blind, placebo-controlled RCT. PMID 33858011, doi:10.1093/ecco-jcc/jjab069, Secondary analysis (endocannabinoid levels): Tartakover Matalon 2021, PMID 34531823, amount used, PMID 42231518, NCT01826188, 50 people, 2013–2018, registered concentration 50 mg/mL CBD + 5 mg/mL THC, no results in the registry) may be this study's registration, the link could not be verified
- Irving 2018. Multicenter pilot RCT. PMID 29538683, doi:10.1093/ibd/izy002, NCT01562314, dose and side effects from the registry), THC content from the Cochrane summary (Kafil 2018, PMID 30406638
- Naftali 2026. Open-label, single-arm pilot study. PMID 42578019, doi:10.1159/000552842, The registration cited in the publication, NCT06353828, was opened after the study ended (March 2024) and describes a 45-person randomized, placebo-controlled phase 2a trial, it does not match this open-label pilot (no results in the registry)
- Kafil 2020 (Cochrane summary). Journal summary of two Cochrane systematic reviews (5 RCTs, 185 people). PMID 31613959, doi:10.1093/ibd/izz233, Cochrane reviews: Kafil 2018, Crohn’s (CD012853, PMID 30407616, PMID 30406638
- Naftali 2013. Placebo-controlled RCT (triple-blind per the registry; Cochrane rated the blinding as high risk of bias). PMID 23648372, doi:10.1016/j.cgh.2013.04.034, NCT01040910, no results in the registry), PMID 24262941, PMID 24418092
- Naftali 2021 (ulcerative colitis). Double-blind, placebo-controlled RCT (single center). PMID 33571293, doi:10.1371/journal.pone.0246871, NCT01040910, last updated December 2011, the design and results of this 32-person study are not in the registry), secondary analysis: Tartakover Matalon 2021, PMID 34531823
- Doeve 2021. Systematic review and meta-analysis (5 RCTs + 15 non-randomized studies). PMID 32675631, doi:10.1097/MCG.0000000000001393
- Kang 2025. Meta-analysis of RCTs (8 studies: 4 Crohn’s disease, 3 ulcerative colitis, 1 both). PMID 39197096, doi:10.1093/ibd/izae158
- Jugl 2026. Systematic review (GRADE; 4 RCTs + 4 observational studies; no meta-analysis). PMID 42231518, doi:10.1186/s42238-026-00456-2, PROSPERO CRD42023411910
- CAG 2019 (Andrews). Professional society position statement (Canadian Association of Gastroenterology; non-comprehensive literature review and expert opinion; no formal evidence grading of the statements). PMID 31294362, doi:10.1093/jcag/gwy064, PMC6507278 (full text read). According to the conflict-of-interest statement, 3 of the 7 authors have ties to companies that make cannabis or cannabinoid products (advisory board and executive role, research support and donated product, speaker fees and advisory board). The same document also appears in the irritable bowel and stomach table
- Gupta 2024. Patient registry analysis (no control group). PMID 39689344, doi:10.1080/17474124.2024.2443574, Earlier analysis of the same registry: Dalavaye 2023, PMID 36562418, 3 months, overlapping sample)
- Fliss Isakov 2023. Prospective case series (no control group). PMID 38201908, doi:10.3390/nu16010078
- Storr 2014. Cross-sectional survey (comparison of patients who use and do not use cannabis). PMID 24407485, doi:10.1097/01.MIB.0000440982.79036.d6
- Glickman 2024. Retrospective cohort, propensity score–matched (TriNetX health records network, US). PMID 37580878, doi:10.1093/ibd/izad151, PMID 37580879, PMID 37738592, PMID 37738640, PMID 39241176, PMID 39361966
- Desai 2019. Retrospective, propensity score–matched analysis (US National Inpatient Sample, 2010–2014); two Mbachi 2019 analyses using overlapping years of the same database are also covered in this row. PMID 31355219, doi:10.21037/atm.2019.04.63, Separate analyses of the same database with overlapping years: Mbachi 2019, Crohn’s (Dig Dis Sci, PMID 30825109, 2012–2014, PMID 31388856, PMID 31393356, PMC6708902, 2010–2014, PMID 31464963
Points that could not be verified from the full text
- The full text of Irving 2018 was not read (paywalled); n, dose and side effects are from the ClinicalTrials.gov record, the THC proportion (at most 4.7%) from the Cochrane summary; the daily THC amount in mg is unknown
- The full texts of Naftali 2013, Naftali 2021 (Crohn’s disease), Doeve 2021, Kang 2025, Storr 2014, Glickman 2024, Gupta 2024 and Desai 2019 could not be read; the rows are based on the abstracts. For Naftali 2021 (Crohn’s disease), the oil’s dosing schedule, the median amount used, the side effect table and the analyses adjusted for age, sex and disease duration were taken not from the main publication but from the data supplement of a systematic review (Jugl 2026) and from a secondary publication on the same patients (Tartakover Matalon 2021); in this secondary publication the oil’s concentration is given as '8 mg/mL CBD and 2 mg/mL THC', which matches the per-drop value
- Naftali 2019 (a 127-patient Israeli series, PMID 31567639) was not included in the table: the disease scores in its abstract (Harvey-Bradshaw from 14 ± 6.7 to 7 ± 4.7) are identical to those of the 2011 study of 30 patients, and the same authors cite these values in 2021 as the result of the 30-patient study; because the full text could not be read, whether these are new data could not be verified. In the Naftali group’s publications, product concentrations differ from source to source (e.g., for the ulcerative colitis cigarette, 16% THC and 80 mg per cigarette in the full text; 23 mg THC a day in Cochrane; 23% THC and 11.5 mg per cigarette in a secondary publication); the table uses the values from the primary publications. The Kang 2025 abstract counts 8 studies, whereas the known separate RCTs number 5; which studies it combined could not be read
Research history
Here we record what changed on this page, when and why, with dates. The newest change is at the top.
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 2026 additional review: sources found for this page during the searches for other topics were read and added to the page. The 2019 position statement of the Canadian Association of Gastroenterology was added to the table. Based on the evidence at the time it was written, the statement says that cannabis did not appear to change the course of Crohn’s disease and ulcerative colitis and that the evidence is insufficient to recommend it as a treatment that reduces inflammation; it also recommends that cannabis not be used in place of approved treatments. The statement is expert opinion without a formal grading of evidence. The evidence summary and the reviews paragraph were updated accordingly. The conclusion and the strength of evidence did not change.
Related studies: CAG 2019 (Andrews), published April 2019 (online November 8, 2018) (PMID 31294362, doi:10.1093/jcag/gwy064, PMC6507278 (full text read). According to the conflict-of-interest statement, 3 of the 7 authors have ties to companies that make cannabis or cannabinoid products (advisory board and executive role, research support and donated product, speaker fees and advisory board). The same document also appears in the irritable bowel and stomach table)
Display fix: internal working notes left over from the previous cleanup were removed; content and evidence did not change.
Older changes (6)
Display fix: leftover internal working file names were removed from the text; content and evidence did not change.
In October 2026, PubMed, Cochrane, ClinicalTrials.gov and Europe PMC were searched systematically; 10 studies were added: one randomized trial each with THC-rich marijuana cigarettes in Crohn’s disease and ulcerative colitis, 3 systematic reviews and meta-analyses, 2 studies following patients in real life, and 3 observational studies linking cannabis use to surgery, hospital admission and disease complications. In existing rows, the following were corrected: the dosing schedule, outcome numbers and adjusted analysis of the CBD/THC oil in Crohn’s disease; the serious event information and registry number of the pure CBD study; and the CBD amount, funding, registry information and product type of the ulcerative proctitis enema; citations for the Cochrane reviews were added. The conclusion and the strength of evidence did not change.
Related studies: Naftali 2013, published October 2013 (PMID 23648372, doi:10.1016/j.cgh.2013.04.034, NCT01040910, no results in the registry), PMID 24262941, PMID 24418092); Naftali 2021 (ulcerative colitis), published February 11, 2021 (PMID 33571293, doi:10.1371/journal.pone.0246871, NCT01040910, last updated December 2011, the design and results of this 32-person study are not in the registry), secondary analysis: Tartakover Matalon 2021, PMID 34531823); Doeve 2021, published October 2021 (PMID 32675631, doi:10.1097/MCG.0000000000001393); Kang 2025, published February 6, 2025 (PMID 39197096, doi:10.1093/ibd/izae158); Jugl 2026, published June 3, 2026 (PMID 42231518, doi:10.1186/s42238-026-00456-2, PROSPERO CRD42023411910); Gupta 2024, published December 2024 (PMID 39689344, doi:10.1080/17474124.2024.2443574, Earlier analysis of the same registry: Dalavaye 2023, PMID 36562418, 3 months, overlapping sample)); Fliss Isakov 2023, published December 26, 2023 (PMID 38201908, doi:10.3390/nu16010078); Storr 2014, published March 2014 (PMID 24407485, doi:10.1097/01.MIB.0000440982.79036.d6); Glickman 2024, published July 3, 2024 (PMID 37580878, doi:10.1093/ibd/izad151, PMID 37580879, PMID 37738592, PMID 37738640, PMID 39241176, PMID 39361966); Desai 2019, published June 2019 (PMID 31355219, doi:10.21037/atm.2019.04.63, Separate analyses of the same database with overlapping years: Mbachi 2019, Crohn’s (Dig Dis Sci, PMID 30825109, 2012–2014, PMID 31388856, PMID 31393356, PMC6708902, 2010–2014, PMID 31464963)
The names of the result labels were simplified: the "No benefit seen" label on this page became "No effect found". The assessment did not change.
PubMed and ClinicalTrials.gov were searched for newly published and previously missed clinical studies. Study added: Naftali 2026. The conclusion and the strength of evidence did not change.
Related studies: Naftali 2026, published January–December 2026 (PMID 42578019, doi:10.1159/000552842, The registration cited in the publication, NCT06353828, was opened after the study ended (March 2024) and describes a 45-person randomized, placebo-controlled phase 2a trial, it does not match this open-label pilot (no results in the registry))
The full texts of the studies were reread and the information on the page was checked against the sources. Corrected: the registry number, number of participants, side effect and dose information in the study table; the dose range in the studies. The conclusion and the strength of evidence did not change.
Page published. This first review examined 4 studies.