How Cannabis Affects Bowel Movements
Cannabis use is associated with decreased constipation risk in healthy adults, but chronic heavy use can paradoxically lead to gastrointestinal distress during withdrawal, including abdominal pain and diarrhea. 1, 2
Effects During Active Cannabis Use
Reduced Constipation
- Recent cannabis users have approximately 30% lower odds of constipation compared to non-users, with this association persisting after adjustment for demographics, comorbidities, medications, diet, and other substance use. 1
- The prevalence of constipation is significantly lower among recent cannabis users (7.5%) versus past/never users (10.2%). 1
- This effect appears counterintuitive given that cannabinoids typically slow colonic motility through the endocannabinoid system. 1
No Effect on Diarrhea
- Cannabis use shows no significant association with increased or decreased diarrhea risk in healthy adults. 1
Gastrointestinal Symptom Burden
- Active cannabis users with inflammatory bowel disease report more frequent gastrointestinal symptoms including abdominal pain (83.3% vs 61.7%), gas (66.7% vs 45.6%), and tenesmus (70.0% vs 47.6%) compared to non-users, despite similar rates of endoscopic inflammation. 3
- Cannabis-based medicines increase gastrointestinal adverse events across multiple conditions with moderate certainty evidence. 4
Effects During Cannabis Withdrawal
Gastrointestinal Withdrawal Symptoms
- Long-term daily cannabis users experience withdrawal symptoms within 24-72 hours of cessation, including abdominal pain, appetite changes, and diarrhea. 5, 2
- Approximately 47% of regular cannabis users experience cannabinoid withdrawal syndrome after cessation of heavy and prolonged use. 2
- Symptoms typically peak between days 2-6, with the acute withdrawal phase lasting 1-2 weeks. 2
Management of Withdrawal-Related Bowel Changes
- Standard antidiarrheal agents such as loperamide are recommended for diarrhea during cannabis withdrawal syndrome. 2
- Ondansetron may be tried for nausea, though efficacy is often limited. 2
- Avoid opioids entirely, as they worsen nausea, carry addiction risk, and do not address underlying pathophysiology. 2
Cannabinoid Hyperemesis Syndrome
A Critical Distinction
- Cannabinoid hyperemesis syndrome occurs during active chronic cannabis use (typically >4 times per week for over a year), not during withdrawal, and is characterized by cyclical vomiting episodes relieved by hot showers. 5
- This syndrome requires cannabis cessation for resolution, with definitive improvement requiring 6+ months of abstinence. 2
- Hot water bathing behavior is pathognomonic, present in 44-71% of cases. 2
Clinical Caveats
High-Risk Populations
- Patients consuming more than 1.5 g/day of inhaled cannabis, more than 20 mg/day of THC-dominant oil, or more than 300 mg/day of CBD-dominant oil face higher risk for withdrawal syndrome. 2
- Those using cannabis products with unknown THC/CBD content more than 2-3 times daily are also at increased risk. 2
Important Pitfall
- Do not confuse cannabis withdrawal syndrome with cannabinoid hyperemesis syndrome—they present oppositely regarding timing of vomiting (after cessation versus during active use). 2