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Does Coffee Really Make You Go to the Bathroom?

In Quebec, coffee imports mainly come from Colombia, Brazil, Honduras and Peru (1). Nearly 70% of the adult Quebec population (19 years and over) consume coffee (2). Many report that coffee has a laxative effect, but why?

Gastrocolic reflex

The gastrocolic reflex is a reflex of the body that occurs when there is an increase in activity in the stomach, resulting in increased motility or movement in the colon. This usually happens after eating a meal and is important in helping to pass fecal matter out of the body.

Both regular and decaffeinated coffee trigger the secretion of a hormone called gastrin. Gastrin signals the stomach to increase production of hydrochloric acid and digestive enzymes, improve stomach contractions, loosen the valve between the small and large intestines, and relax the sphincter between the stomach and small intestine, among other effects. To summarize these various influences, we can say that gastrin facilitates the digestive process. Therefore, if coffee induces the release of gastrin and gastrin, in turn, aids digestion, this pathway could serve as the mechanism by which coffee triggers bowel movements (3).

However, it's important to note that not everyone reacts the same to drinking coffee, and some people may be more sensitive to caffeine than others. Additionally, excessive coffee consumption can have negative effects on the body, such as increased heart rate, anxiety, and sleep disturbances.

Although coffee can have an effect on the gastrocolic reflex, it is important to consume it in moderation and be careful of the possible negative effects it can have on the body.

Time of the day

Morning coffee does not have the same laxative effect as afternoon coffee. The gastrocolic reflex is said to be more active in the morning (4).

In conclusion, the laxative effect associated with coffee is explained by the gastrocolic reflex, triggered by caffeine stimulating the production of stomach acid and increasing colon motility. However, individual responses to caffeine vary, and excessive consumption can cause adverse effects. It is therefore crucial to enjoy coffee in moderation, while taking into account the potential repercussions on health, and to note that the time of day influences the intensity of this laxative effect, with greater activity of the gastro-colic reflex. The morning.

Karine Drouin Dt.P. nutritionniste et diététiste




2: Plante C, Blanchet C, Rochette L. (2020) Consumption of other foods and drinks among Quebecers. Collection: A look at the diet of Quebecers. Number 4: National Institute of Public Health of Quebec. Quebec. 28 p.

3- Acquaviva F, DeFrancesco A, Andriulli A, Piantino P, Arrigoni A, Massarenti P, Balzola F. Effect of regular and decaffeinated coffee on serum gastrin levels. J Clin Gastroenterol. 1986 Apr;8(2):150-3. doi:10.1097/00004836-198604000-00009. PMID: 3745848.

4 - Malone, J.C., Thavamani, A. (2023). National Center for Biotechnology Information. Gastrocolic Reflex. Found on December 9, 2023 online at

Brown SR, Cann PA, Read NW. (1990). Effect of coffee on distal colon function. Gut, 31:450-453.

Lohsiriwat, S., Kongmuang, P., & Leelakusolvong, S. (2008). Effects of caffeine on anorectal manometric findings. Diseases of the colon and rectum, 51(6), 928–931.

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