Cannabis Use Was Linked to Lower Odds of Constipation, but It Is Not a Proven Treatment
A 2019 analysis found that adults who had recently used cannabis reported constipation less often than people who had used it in the past or never used it. The finding is intriguing, but it does not show that cannabis prevents or treats constipation.
The study, published in the American Journal of Gastroenterology, examined data from 9,645 U.S. adults ages 20 to 59 who participated in the National Health and Nutrition Examination Survey between 2005 and 2010. Constipation affected 7.5% of recent cannabis users, compared with 10.2% of past or non-users. After statistical adjustments, recent users had approximately 30% lower odds of constipation.
Because the research was based on survey data, it can identify an association but not cause and effect. The study did not assign people to use cannabis, measure whether cannabis relieved constipation, or establish how much participants used. Differences in diet, lifestyle, other health conditions, medications, and reasons for using cannabis may also have influenced the results.
Why the finding is unexpected
Cannabinoids can affect the enteric nervous system and the movement of the digestive tract. Experimental and clinical research has generally associated cannabinoid signaling—particularly through THC—with slowed gastrointestinal motility in some circumstances. That makes the lower constipation rate among recent users difficult to explain.
The study’s authors suggested several possible explanations. Cannabis contains many compounds, and some less-studied cannabinoids or other plant components could affect gut movement differently from THC. Cannabis may also influence appetite, pain perception, or other behaviors that indirectly affect bowel habits. These possibilities remain hypotheses, not established treatments.
A review of cannabinoids and gastrointestinal motility similarly describes a complex relationship involving motility, secretion, visceral pain, and the gut’s nervous system. The available evidence does not support using cannabis as a first-line therapy for constipation.
Potential risks
Using cannabis for digestive symptoms can also create problems. Heavy, long-term use has been linked to cannabinoid hyperemesis syndrome, which causes repeated episodes of severe nausea, vomiting, and abdominal pain. The condition can lead to dehydration and other complications, and stopping cannabis is the definitive treatment.
Nor should the constipation finding be interpreted as evidence that cannabis treats inflammatory bowel disease or reduces intestinal inflammation. Cannabis-based products may help some patients manage symptoms such as pain or nausea, but symptom relief is not the same as treating the underlying disease. Anyone considering cannabis for a gastrointestinal condition should discuss the potential benefits, risks, drug interactions, and legal considerations with a health professional.
Established approaches to constipation
For occasional constipation, standard measures are better supported. The National Institute of Diabetes and Digestive and Kidney Diseases recommends gradually increasing dietary fiber, drinking enough fluids, staying physically active, and establishing a regular time for bowel movements. Adults generally need 22 to 34 grams of fiber per day, depending on age and sex.
Short-term over-the-counter options, including fiber supplements and osmotic laxatives, may be appropriate for some people. Persistent constipation may require prescription medication, evaluation for an underlying condition, or treatments such as biofeedback. The NIDDK constipation treatment guide outlines these options.
Seek medical advice if constipation does not improve, keeps returning, or occurs with rectal bleeding, blood in the stool, ongoing abdominal pain, vomiting, unexplained weight loss, or a sudden change in bowel habits. For now, the cannabis research is best viewed as an unexpected observational finding that warrants further study—not as a recommendation to use cannabis for constipation.
