In a placebo-controlled trial, THC-rich cannabis cigarettes produced a clinical response in 90% of treatment-resistant Crohn's disease patients versus 40% on placebo, with three patients weaned off steroids and improvements in appetite and sleep.
Read this if you have Crohn's disease that has not responded to standard treatments.
90% clinical response to cannabis vs. 40% placebo in treatment-resistant Crohn's
The Backstory
Crohn's disease is not a stomachache. It is a chronic inflammatory assault on the gastrointestinal tract that can bore holes through the bowel wall, create tunnels between organs, and progressively destroy sections of intestine that must be surgically removed. The pain is relentless. The fatigue is crushing. The dietary restrictions, the urgency, the social isolation — patients describe it as a disease that colonizes every aspect of life.
The standard treatments are powerful but imperfect. Steroids control flares but ravage the body with prolonged use. Immunomodulators suppress the immune system broadly. Biologic drugs like infliximab target specific inflammatory pathways but cost tens of thousands of dollars annually and stop working in a significant minority of patients. When all of these fail — and in roughly 20-30% of patients, they eventually do — patients are left with few options and mounting desperation.
It was in this context that Timna Naftali, a gastroenterologist at Meir Medical Center in Israel, decided to do something no one had done before: run a proper placebo-controlled trial of cannabis for Crohn's disease.
The Study
Naftali and colleagues at the Department of Gastroenterology and Hepatology at Meir Medical Center, affiliated with Tel Aviv University's Sackler Faculty of Medicine, enrolled 21 patients with active Crohn's disease who had failed everything.
Study Design
The First Placebo-Controlled Cannabis Trial for Crohn's Disease
21
Patients enrolled
all with treatment-resistant disease (CDAI > 200)
Failed
Prior treatments
steroids, immunomodulators, AND anti-TNF biologics
115 mg
THC per cigarette
smoked twice daily for 8 weeks
Placebo
Control group
cannabis cigarettes with THC extracted — identical appearance
Naftali et al. (2013), Clin Gastroenterol Hepatol 11(10):1276-1280
The design was elegant in concept: cannabis cigarettes containing 115 mg of THC versus placebo cigarettes made from the same plant material with THC chemically extracted. The flower looked the same, smelled similar, and was rolled identically. Patients smoked twice daily for 8 weeks, with a 2-week follow-up washout period.
The primary endpoint was remission — defined as a Crohn's Disease Activity Index (CDAI) score below 150. The secondary endpoint was clinical response — a drop in CDAI of at least 100 points. This distinction would prove critical to understanding what the study actually found versus what the world would claim it found.
The Results
90%
clinical response rate in the cannabis group — 10 of 11 patients showed meaningful improvement (CDAI drop ≥ 100), compared to 40% (4 of 10) in the placebo group (p = 0.028).
But the primary endpoint — complete remission — was not met. Only 5 of 11 (45%) achieved remission on cannabis versus 1 of 10 (10%) on placebo. This difference was not statistically significant (p = 0.43).
Naftali et al. (2013), Clin Gastroenterol Hepatol
Read that again carefully, because it contains the single most misunderstood result in the history of cannabis research.
The cannabis group improved dramatically. CDAI scores dropped from 330 to 152 in the treatment group versus 373 to 306 in placebo. Three patients were weaned off corticosteroids entirely. Appetite improved. Sleep improved. Pain decreased. For patients who had exhausted every approved treatment option, this was life-changing relief.
But the primary endpoint failed. The study was designed to test whether cannabis could induce remission. It could not — at least not at a rate statistically distinguishable from placebo in this small sample.
Critical Distinction
Response vs. Remission: Why the Difference Matters
Clinical response
A meaningful improvement in symptoms — CDAI drops by 100+ points. The patient feels substantially better.
Clinical remission
The disease is effectively controlled — CDAI falls below 150. The patient is functionally well.
Why it matters
Response means improvement. Remission means the disease is under control. For a chronic condition like Crohn's, response without remission means patients feel better but the disease may still be progressing.
What Naftali found
Cannabis achieved response (90% vs 40%), but not remission at a statistically significant rate (45% vs 10%, p = 0.43)
Naftali et al. (2013)
What the Internet Got Wrong
Within months of publication, the study went viral — and the nuance was the first casualty.
Myth vs. Reality
A new study proves marijuana causes complete remission of Crohn's disease
The study explicitly states that its primary endpoint — remission — was NOT achieved. Cannabis produced significant clinical improvement (response) but could not induce complete remission at a statistically significant rate.
The Evidence
Snopes rated this claim FALSE. The study's own conclusion begins: 'Although the primary end point of the study (induction of remission) was not achieved...'
Headlines stripped away the critical distinction between response and remission. "Cannabis cures Crohn's" ricocheted across social media. Snopes eventually published a fact-check rating the claim FALSE, documenting years of viral misrepresentation of a single 21-person pilot study. Celebrity endorsements amplified the distortion further.
The irony is that the actual findings were remarkable enough without exaggeration. A 90% clinical response rate in patients who had failed every available treatment is extraordinary. Three patients off steroids is clinically meaningful. But "helps symptoms significantly" doesn't go viral. "Cures Crohn's" does.
This pattern — legitimate promising research distorted into miracle claims — is one of the most persistent problems in cannabis science communication. It undermines the credibility of real research and creates unrealistic expectations for patients who desperately need accurate information.
Why Cannabis Affects the Gut
The gastrointestinal tract is one of the most cannabinoid-rich environments in the body. The biological basis for cannabis affecting Crohn's disease is not speculation — it is well-established physiology.
Biological Mechanism
The Endocannabinoid System in the Gut
Proposed mechanism
This multi-target mechanism — simultaneously addressing inflammation, barrier function, motility, and pain — explains why cannabis produces such broad symptomatic improvement in IBD patients. It also explains a critical limitation: the symptom relief may outpace and mask the actual anti-inflammatory effect, making patients feel better while disease progression continues silently.
The Naftali Arc: A Decade of Evidence
Naftali's 2013 trial was not an isolated experiment. It was the centerpiece of a systematic research program that has unfolded over more than a decade — and the later studies add crucial context.
Research Timeline
Naftali's Cannabis-IBD Research Program
Historical research record
The 2021 follow-up is the study that completes the picture. It confirmed the symptomatic benefit first observed in 2013 while revealing its critical limitation: cannabis makes Crohn's patients feel better without healing the underlying inflammation. In modern IBD treatment, where mucosal healing is the gold standard for disease control, this distinction is everything. Feeling better while inflammation silently progresses means continued tissue damage, stricture formation, and eventual surgical intervention.
The Controversy
The editorials that accompanied publication exposed the scientific community's ambivalence.
Schicho and Storr, writing in Pharmacology, praised the trial as confirmation of "what has been suggested for a long time from experimental studies" — that cannabinoids have genuine anti-inflammatory potential in IBD. They emphasized the strong preclinical rationale and called for larger studies.
But Vu, Melmed, and Targan from Cedars-Sinai's IBD Center struck a more cautious note in their editorial "Weeding out the facts: the reality about cannabis and Crohn's disease." They highlighted the blinding problem — almost every patient could tell whether they were receiving cannabis or placebo due to psychoactive effects. Except for two placebo patients, all participants correctly identified their group assignment.
Methodological Concerns
What the Critics Said
Blinding failure
Nearly all participants knew their group assignment — effectively unblinding the trial and potentially inflating the response rate through expectation effects
Sample size
21 patients is far too small for definitive conclusions. The Cochrane Collaboration assigned 'very low certainty' to this evidence
Age imbalance
Cannabis patients were approximately 10 years older than placebo patients — a potential confound in an inflammatory disease
Smoking route
Cannabis cigarettes are the worst possible delivery method for an inflammatory bowel disease — combustion products irritate the GI tract
No biomarkers
Inflammatory markers (CRP) did not significantly change, raising questions about whether the benefit was anti-inflammatory or purely symptomatic
Vu, Melmed & Targan (2014), Clin Gastroenterol Hepatol; Cochrane Systematic Review (2018)
The Cochrane Collaboration's 2018 systematic review was the most damning formal assessment. It assigned the evidence "very low certainty" and concluded that "no firm conclusions regarding the efficacy and safety" of cannabis for Crohn's disease could be drawn from this trial alone. The review cited high risk of bias from blinding failure, small sample size, sparse data, and very serious imprecision.
The Bigger Question: Feeling Better vs. Being Better
This study crystallizes a tension that runs through much of cannabis medicine: the gap between symptomatic relief and disease modification.
For a patient with treatment-resistant Crohn's who cannot eat, cannot sleep, and lives in constant pain, symptom relief is not trivial. It is the difference between functioning and not functioning. Three patients in this trial stopped taking corticosteroids — drugs that cause osteoporosis, diabetes, cataracts, and adrenal suppression with long-term use. That matters.
But Crohn's is a progressive disease. Uncontrolled inflammation causes cumulative, irreversible damage. Strictures narrow the bowel. Fistulas create abnormal connections between organs. Each surgical resection removes intestine that cannot be replaced. If cannabis makes a patient feel well enough to delay or refuse proven anti-inflammatory therapy, the long-term outcome could be worse despite the short-term improvement.
This is precisely what Naftali's 2021 follow-up confirmed: cannabis improved symptoms and quality of life, but endoscopy showed the gut inflammation was unchanged. The patients felt better. The disease was not.
The Researcher
Timna Naftali is a professor of gastroenterology at Tel Aviv University's Sackler Faculty of Medicine and heads the IBD service at Meir Medical Center in Kfar Saba, Israel. She was the first researcher to conduct controlled clinical trials of cannabis for inflammatory bowel disease — a decision that required significant professional courage in a field where cannabis research carried stigma.
She established the Gastro Cannabis Laboratory at Meir Medical Center to investigate the mechanisms by which cannabinoids affect the gastrointestinal tract. Her research program has been notably honest: when her CBD trial failed (2017), she published it. When her larger trial showed symptom benefit without mucosal healing (2021), she reported both findings without spin. Her body of work represents the most rigorous clinical investigation of cannabis for IBD in the world.
What This Means Today
Does cannabis treat Crohn's disease?
Cannabis significantly improves symptoms in patients with active Crohn's disease, including pain, appetite, sleep, and overall well-being. However, controlled trials have not shown that it induces reliable remission or heals gut inflammation. It appears to be a potent symptomatic treatment rather than a disease-modifying therapy. Patients should not substitute cannabis for proven anti-inflammatory treatments without medical guidance.
Should Crohn's patients try cannabis?
This is a conversation for your gastroenterologist. Cannabis may be a reasonable adjunct for symptom management, especially in patients who have not responded to conventional therapy. But it should not replace immunomodulators or biologics that target the underlying inflammation. Non-smoked preparations (oils, capsules, vaporization) are strongly preferred — smoking is a known trigger for Crohn's flares.
Why did the media say cannabis 'cures' Crohn's?
The study was widely misinterpreted. The 90% clinical response rate (symptom improvement) was conflated with remission (disease control). Snopes rated the viral claim that cannabis causes "complete remission of Crohn's disease" as FALSE. The study's own conclusion states that its primary endpoint of remission induction was not achieved.
Did the CBD-only trial work?
No. Naftali's 2017 follow-up testing low-dose CBD alone (10 mg twice daily) for Crohn's showed no benefit over placebo. This suggests THC, not CBD, drives the symptomatic improvement — though the CBD dose may have been too low for meaningful effect.
Cannabis induces a clinical response in patients with Crohn's disease: a prospective placebo-controlled study
Naftali T, Bar-Lev Schleider L, Dotan I, Lansky EP, Sklerovsky Benjaminov F, Konikoff FM (2013) · Clinical Gastroenterology and Hepatology
Related Research
Key studies in this area
CBD-Rich Cannabis Induces Clinical but Not Endoscopic Response in Crohn's
Naftali et al. (2021)
Low-Dose CBD Is Not Effective for Crohn's Disease
Naftali et al. (2017)
Cannabis for Inflammatory Bowel Disease
Naftali et al. (2014)
CBG for Inflammatory Bowel Disease
Borrelli et al. (2013)
What the researchers found
Twenty-one patients with active Crohn's disease (CDAI >200) who had failed steroids, immunomodulators, and anti-TNF agents were randomized to cannabis cigarettes (115 mg THC twice daily) or placebo cigarettes (cannabis with THC extracted). After 8 weeks, 10 of 11 cannabis patients (90%) achieved clinical response (CDAI drop >100 points) versus 4 of 10 on placebo (40%, p=0.028).
The primary endpoint of complete remission (CDAI <150) was not met, with 5 of 11 (45%) achieving remission on cannabis versus 1 of 10 (10%) on placebo (p=0.43). Three patients in the cannabis group were weaned from corticosteroid dependency. Patients reported improved appetite and sleep with no significant side effects.
Why it matters
This was the first placebo-controlled trial of cannabis for Crohn's disease. The patients had failed all available treatments, making any clinical benefit significant. The 90% clinical response rate, combined with steroid weaning and symptom improvement, suggests cannabis may have genuine therapeutic value for inflammatory bowel disease.
The numbers in context
21 patients, CDAI >200. Treatment failures: steroids, immunomodulators, anti-TNF. Cannabis: 115 mg THC twice daily for 8 weeks. Clinical response: 90% cannabis vs. 40% placebo (p=0.028). Complete remission: 45% vs. 10% (NS). 3 patients weaned from steroids.
How the study worked
Prospective, randomized, placebo-controlled trial. 21 patients with treatment-resistant Crohn's disease (CDAI >200 despite steroids, immunomodulators, anti-TNF). Cannabis cigarettes containing 115 mg THC vs. THC-extracted placebo, twice daily for 8 weeks. Follow-up for 2 additional weeks.
What this study cannot tell us
Very small sample (21 patients). The primary endpoint (remission) was not met. Blinding may have been compromised due to psychoactive effects. The short duration (8 weeks) does not address long-term outcomes. Smoking as the delivery route is not ideal for long-term use. Benefits may have been partly symptomatic rather than anti-inflammatory.
How to read the evidence
Placebo-controlled RCT with significant results; strong evidence despite small sample size, given the treatment-resistant population.
When this study was published
Published in 2013. This was a landmark trial that stimulated further research into cannabinoids for inflammatory bowel disease.
The bigger picture
This trial provided the first controlled evidence supporting what inflammatory bowel disease patients had been reporting anecdotally: cannabis helps Crohn's disease. While the primary endpoint was missed, the clinical response data were compelling, especially in a population where all other treatments had failed.
Questions still open
- Would longer treatment achieve more remissions? Is the benefit anti-inflammatory or purely symptomatic? Would non-smoked cannabis preparations work as well? Does CBD alone or in combination with THC perform differently for Crohn's disease?
Common questions
Does cannabis treat Crohn's disease?
Should Crohn's patients try cannabis?
Read the original research
Cannabis induces a clinical response in patients with Crohn's disease: a prospective placebo-controlled study.
Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association, 11(10), 1276-1280.e1
Citation
Naftali, Timna; Bar-Lev Schleider, Lihi; Dotan, Iris; Lansky, Ephraim Philip; Sklerovsky Benjaminov, Fabiana; Konikoff, Fred Meir. (2013). Cannabis induces a clinical response in patients with Crohn's disease: a prospective placebo-controlled study.. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association, 11(10), 1276-1280.e1. https://doi.org/10.1016/j.cgh.2013.04.034
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