Meta-analysis finds extremely limited evidence for marijuana in Crohn's disease or ulcerative colitis | Research

The takeaway

A meta-analysis of only 3 eligible trials (71 patients total) found no significant difference between marijuana and placebo for achieving remission or clinical response in IBD, with very low quality evidence.

IBD patients considering cannabis, gastroenterologists, medical cannabis researchers

Only 3 eligible trials with 71 total patients; no significant benefit; GRADE quality very low

What the researchers found

For UC (1 trial, 60 patients): no difference in remission (RR 1.02) or response (RR 0.99). Adverse events higher with marijuana (RR 1.28). For Crohn's (2 trials, 40 patients): no significant difference in remission (RR 0.72) or response (RR 0.15, borderline). GRADE quality: low to very low.

Why it matters

Despite widespread patient use of marijuana for IBD, this meta-analysis reveals that the controlled trial evidence base is almost nonexistent, with only 71 total patients across all eligible trials.

The numbers in context

334 studies screened; 3 eligible (1 UC, 2 Crohn's). UC: 29 marijuana vs. 31 placebo. Crohn's: 21 marijuana vs. 19 placebo. No significant differences in remission or response. GRADE: low to very low.

How the study worked

Meta-analysis following PRISMA guidelines. Systematic search of PubMed, Embase, and Web of Science (June 2019). Of 334 studies reviewed, only 3 RCTs met eligibility. GRADE methodology assessed evidence quality.

What this study cannot tell us

Only 3 trials eligible; extremely small total sample (71 patients); heterogeneous cannabis preparations; GRADE quality low to very low; cannot rule out benefit that larger trials might detect.

How to read the evidence

Meta-analysis with GRADE assessment, but severely limited by only 3 tiny eligible trials.

When this study was published

Published in 2020.

The bigger picture

The enormous gap between how commonly patients use cannabis for IBD and how little controlled evidence exists represents one of the most striking disconnects in cannabinoid medicine.

Questions still open

Will larger, well-designed trials reveal benefits obscured by small sample sizes? Which IBD patients, if any, are most likely to benefit from cannabinoid therapy?

Common questions

Does marijuana help Crohn's disease or ulcerative colitis?

Based on the only 3 controlled trials that exist (71 patients total), there is no statistically significant evidence of benefit. The evidence quality was rated as very low, meaning definitive conclusions cannot be drawn in either direction.

Why are there so few trials?

Cannabinoid research faces regulatory barriers, funding challenges, and difficulty blinding cannabis interventions. Despite widespread patient use, the controlled trial evidence base for IBD remains almost nonexistent.

Read the original research

Evidence supporting the benefits of marijuana for Crohn's disease and ulcerative colitis is extremely limited: a meta-analysis of the literature.

Annals of gastroenterology, 33(5), 495-499

View on PubMed ↗Publisher’s paper ↗

Citation

Desmarais, Anna; Smiddy, Stephen; Reddy, Sneha; El-Dallal, Mohammed; Erlich, Jonathan; Feuerstein, Joseph D. (2020). Evidence supporting the benefits of marijuana for Crohn's disease and ulcerative colitis is extremely limited: a meta-analysis of the literature.. Annals of gastroenterology, 33(5), 495-499. https://doi.org/10.20524/aog.2020.0516