Here’s Why Coffee Makes You Poop, Explained by a G.I. Doctor and Science

For many coffee lovers, the bathroom trip after a morning brew is as predictable as the sunrise. But why is coffee one of the drinks that make you poop immediately, even if it’s decaf?

While caffeine does help wake up your gut, it’s the coffee bean itself that triggers this urge, says Josephine Ni, MD, a University of Texas Southwestern gastroenterologist and expert on inflammatory bowel diseases.

Does caffeine make you go to the bathroom?

Put simply, yes. Caffeine doesn’t just wake up your brain—it boosts gut activity, too. Specifically, caffeine stimulates your colon, triggering bowel contractions that help move stool along, Dr. Ni explains. At the same time, caffeine “lowers the sensory threshold for the desire to defecate,” she says, meaning that your body is more sensitive to signals from your gut that it’s time to go. 

But interestingly, as a 2022 study published in Nutrients found, rats given decaf coffee had similar bowel movement patterns as those given caffeinated coffee. This suggested that other compounds in coffee are at play, too. 

Here’s why coffee triggers a bowel movement

Dr. Li says coffee raises gastrin levels. This hormone triggers what’s called the “gastrocolic reflex”—the signal your brain sends your gut when your stomach is full, prompting the urge to poop. The reflex occurs whenever our body is ready for a bowel movement, but coffee amplifies its effect. 

She says that coffee also boosts another hormone called cholecystokinin (CCK). This chemical messenger tells your pancreas to release digestive enzymes and makes your gallbladder contract to release bile—both important steps in the chain of events that lead up to a bowel movement. 

Coffee’s acidity likely plays a role, too, according to Kris Sollid, RD, the senior director of research and consumer insights at the International Food and Information Council. When coffee raises our gastrin hormone levels, the body produces more gastric acid to kick-start digestive processes. Coffee also contains chlorogenic acid, a plant-based antioxidant.

Sollid explains that both of these acids lower the pH of the stomach and speed up the movement of food from the stomach to our intestines, forcing the stomach to push out its contents faster than it would on its own.

Can you prevent the urge to poop?

While pooping after a morning latte is routine for many people, it’s not just a habit. “Coffee’s pro-motility effects have been measured against placebo [effect],” Dr. Ni says, and the need to poop post-coffee comes from how coffee moves your digestive system along, not just the routine. 

“Some people do develop a tolerance to the laxative effects of coffee over time,” she adds. But this is likely due to a greater tolerance to coffee’s caffeine, not its other compounds. That’s why switching to decaf won’t necessarily reduce coffee’s bowel-stimulating effects. For example, “both caffeinated and decaffeinated coffee have been shown to stimulate gastrin and CCK release,” Dr. Ni says. 

Is this a healthy stimulus-reaction event?

In most cases, coffee’s effect on your GI system is a normal response. In fact, drinking coffee is linked to better gut health and a range of other benefits. According to 2025 research published in the European Heart Journal, moderate coffee consumption is associated with a lower risk of type 2 diabetes, heart disease, and all-cause death—especially when you drink it in the morning. 

Still, Dr. Ni says that some people are more sensitive to coffee and its effects, especially people with underlying GI (gastrointestinal) diseases such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). “Coffee can serve as a trigger for their symptoms,” but she says more studies are needed to understand this difference in sensitivity among individuals. 

There are also factors that might make your brew a bit too stimulating. “Coffee syrups can contain sugar alternatives, such as sugar alcohols, which are osmotic laxatives,” Dr. Ni says. “Also, the addition of dairy—to which over one-third of Americans are intolerant—can cause GI symptoms and contribute to the urge to defecate.”

If you’re sensitive to coffee’s laxative activity, try drinking it black to see if you’re reacting to something you’re adding to your mug. Or, Dr. Ni suggests trying tea or a caffeinated soda for your pick-me-up instead. But if you’re experiencing uncomfortable bowel movements post-coffee, Sollid recommends discussing GI symptoms with your doctor to check for possible underlying health issues, such as a gastrointestinal disorder. 

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