CBD has shown promise in a number of gastrointestinal disorders, particularly autoimmune problems like Crohn’s. But a recent clinical trial of CBD may put a damper on hopes for treating ulcerative colitis. The study, run by British doctors and supported by GW pharmaceuticals, sought to test the potential of a CBD-rich extract. CBD did not appear to cause a remission of ulcerative colitis, which was the primary aim of the study. Each capsule contained 50 mg CBD and «an appreciable amount of THC,» which is an unfortunately vague description. Patients were instructed to take four capsules per day at first, and increase up to ten capsules (500 mg CBD), split across two doses each day. But many patients took less, stopping at about 300 mg CBD per day. There appeared to be a beneficial effect of CBD on ulcerative colitis symptoms among the patients who used the full dose, but post-hoc analyses like these are more likely to be false positive results. Quality-of-life measures also improved with CBD treatment. The data were not strikingly positive, but different experimental designs may prove more effective. The study was designed with the expectation that CBD causes remission in 50% of ulcerative colitis cases. It may be that CBD can be helpful but is not as powerful a medication as the authors had hoped. Or, since patients didn’t take the full dose, formulating the extract as an under-the-tongue tincture may be more appropriate. The use of a CBD-rich extract, rather than an isolate, is promising, but a chemical profile of the extract should have been provided with the article for the sake of reproducibility. And finally, the CBD extract was safe in this group of patients. The placebo group reported more side effects, presumably due to the ongoing disease.