Uh, Is It Always Normal To Poop After Drinking Coffee? Here's What The Science Says

If you find that your morning cup of Joe gets things moving in the GI department, you’re not alone. Most people are aware that coffee can have a stimulating effect on the body, including the digestive system, but why does your brain immediately call a code brown after drinking coffee?

Although not everyone is affected in the same way, coffee stimulates the urge to poop in a large number of people. Studies show1 that around 33% of people feel an urgent need to poop after drinking regular and decaf coffee. Interestingly, this effect seems to impact women more than men. 

Though most people think that it’s only the caffeine in coffee that promotes the urge to poop, other compounds found in coffee also contribute to its powerful laxative effects. This is because the substances found in coffee, including caffeine and polyphenols, affect the smooth muscles lining your gut. 

Coffee gets things moving by stimulating muscle contractions in your colon, the area in your digestive system that stores and expels poop. Both regular and decaf coffee have this effect on your colon, but caffeinated coffee has a more powerful impact on your GI system.

Studies show that, compared to water, caffeinated coffee increases colon contractions by 60%2. This increase in colon activity happens in as little as four minutes after sipping on a strong brew, which is why you may feel the immediate urge to run to the bathroom halfway through your coffee. 

The ingredients in coffee also stimulate hormones involved in something called the gastrocolic reflex, which is a natural process3 that occurs after eating that triggers the urge to poop. This reflex controls the movement of food through the GI tract, pushing food down toward your rectum in order to make room for more food.

It’s clear that caffeinated coffee has a strong impact on your bowels, but what about decaf? And can coffee additives and the temperature of coffee impact your gut as well?

It turns out that even though caffeinated coffee has a stronger stimulatory effect on your bowels, decaf coffee can also increase the urge to poop. 

Compared to decaf, caffeinated coffee has a 23% greater impact1 on colon contractions. But decaf coffee also contains poop-stimulating compounds. All coffee provides substances like chlorogenic acids and melanoidins, which scientists think have something to do with the bowel-stimulating effects of decaf coffee.

A 2015 study that included 105 people undergoing bowel surgery found that postoperative treatment with 100 mL of decaf coffee three times per day reduced the time it took for patients4 to have their first postsurgical bowel movement compared to water and caffeinated coffee.

While black coffee has a direct impact on your bowels, ingredients commonly added to coffee can wreak havoc on some people’s GI systems and cause an urgent need to run to the bathroom.

For example, if you’re intolerant to lactose5, a sugar found in milk and dairy products, drinking a milk-containing coffee bev, like a latte or cappuccino, will likely trigger symptoms like gas, bloating, and diarrhea.

Some sugar alternatives can also cause GI symptoms. Sugar alcohols like sorbitol6 are poorly absorbed by the large intestine. They increase pressure in the colon and prevent water absorption, which can trigger diarrhea, especially if they’re consumed in large amounts.

People with gut conditions7 like irritable bowel syndrome and inflammatory bowel disease may be particularly sensitive to sugar alcohol-based sweeteners because they’re poorly absorbed by the body and can cause or worsen symptoms like diarrhea and bloating. 

If you’re into hot coffee, you may experience a stronger urge to visit the bathroom after enjoying your drink compared to people who prefer cold coffee drinks.

"The warm temperature of the liquid9 may stimulate motility," integrative gastroenterologist Marvin Singh, M.D. previously told mindbodygreen. 

Studies show10 that drinking warm liquids may stimulate intestinal movement and gastric emptying, or the time it takes for food to empty out of your stomach, while cold drinks have the opposite effect. 

A 2019 study published in the European Journal of Nutrition found that the consumption of 35 degrees Fahrenheit water slowed gastric motility10, while 140 degrees Fahrenheit water increased gastric motility. 

This means that, theoretically, drinking a hot coffee might have a stronger bowel-stimulating effect compared to drinking an iced coffee. (FYI, hot coffee11 is usually served at temps between 160 and 185 degrees Fahrenheit.)

Finally, even though coffee can help you have regular and consistent bowel movements, you shouldn’t be dependent on coffee’s poop-stimulating effects. 

If you find that you can’t have a bowel movement without coffee, that can be a sign that something’s off with your GI system. "A lot of people will use coffee to help them go to the bathroom, which is a red flag," Alexis Cowan, Ph.D., a metabolic health expert, previously explained on the mindbodygreen podcast. "[Make sure] you're not using it as a way to promote a natural bodily function."

For many of us, coffee can trigger the urge to run to the bathroom. Compounds found in caffeinated and decaf coffee stimulate muscles in the large intestine, which gets things moving in the poop department, and fast!

As long as you’re not dependent on coffee in order to have a bowel movement and you’re not experiencing symptoms like diarrhea, gas, and bloating after drinking coffee, it’s perfectly healthy to keep coffee as a part of your daily routine.