Cannabis is associated with clinical but not endoscopic remission in ulcerative colitis: A randomized controlled trial

PLoS One. 2021 Feb 11;16(2):e0246871. doi: 10.1371/journal.pone.0246871. eCollection 2021.


Background: Cannabis is often used by patients with ulcerative colitis, but controlled studies are few. We aimed to assess the effect of cannabis in improving clinical and inflammatory outcomes in ulcerative colitis patients.

Methods: In a double-blind, randomized, placebo-controlled trial, patients received either cigarettes containing 0.5 g of dried cannabis flowers with80mgTetrahydrocannabinol (THC)or placebo cigarettes for 8 weeks. Parameters of disease including Lichtiger disease activity index, C reactive protein (CRP), calprotectin, Mayo endoscopic score and quality of life (QOL) were assessed before, during and after treatment.

Results: The study included 32 patients. Mean age was 30 years, 14 (43%) females. Lichtiger index improved in the cannabis group from 10.9 (IQR 9-14) to5 (IQR 1-7), (p<0.000), and in the placebo group from 11 (IQR 9-13) to 8 (IQR 7-10)(p = 0.15, p between groups 0.001). QOL improved in the cannabis group from 77±4 to 98±20 (p = 0.000) but not in the placebo group (78±3 at week 0 and 78±17 at week 8;p = 0.459; p between groups 0.007). Mayo endoscopic score changed in the cannabis group from 2.13±1 to 1.25±2 (p = 0.015) and in the placebo group from 2.15±1to 1.69±1 (p = 0.367, p between groups 0.17).

Conclusion: Short term treatment with THC rich cannabis induced clinical remission and improved quality of life in patients with mild to moderately active ulcerative colitis. However, these beneficial clinical effects were not associated with significant anti-inflammatory improvement in the Mayo endoscopic score or laboratory markers for inflammation.( NCT01040910).

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Colitis, Ulcerative / diagnostic imaging
  • Colitis, Ulcerative / drug therapy*
  • Double-Blind Method
  • Endoscopy
  • Female
  • Humans
  • Male
  • Medical Marijuana / therapeutic use*
  • Quality of Life*
  • Remission Induction / methods*
  • Severity of Illness Index
  • Treatment Outcome


  • Medical Marijuana

Associated data


Grants and funding

Funding: the cannabis used in the study was supplied by Tikun Olam, Israel. otherwise there was no funding.