Why Does Coffee Make You Poop? Here's What Doctors Say

Is it you? Or is it the coffee?

Reviewed by Dietitian Maria Laura Haddad-Garcia

Coffee is likely the first thing on your mind every morning. It jump-starts the brain by boosting your energy, which is why people worldwide drink an estimated 500 billion cups daily, according to a 2021 article in the International Journal of Environmental Research and Public Health. Above and beyond the energy boost, coffee might also make you poop soon after it hits your digestive system.

Have you ever wondered what exactly causes that reaction? Doctors, including a gastroenterologist, help us to answer that question.

Related: Does Oatmeal Cause or Relieve Constipation? Here's What a Dietitian Says

Why Coffee Makes You Poop

There are numerous reasons why coffee makes you poop. These are the most common ways it affects the digestive system while you prepare for your day.

It Wakes Up Your Colon and Causes Contractions

Your mind isn't the only thing that goes to sleep every night. When you go to sleep, your digestive function slows down.

And when you wake up, the first thing you eat or drink reactivates that system. If coffee is the first part of your daily diet, it instantly gets your colon working.

Muscle contractions and relaxations in your digestive system, also known as peristalsis, make your body move food through your colon. According to a 2020 review in Nutrients, these contractions may start within four minutes of drinking coffee. Any stool in your colon may begin moving toward your rectum as the rest of your body wakes up.

It Increases Gastrin Production

As your morning coffee energizes your mind, it also kick-starts numerous bodily functions. According to a 2022 narrative review from Nutrients, it specifically stimulates production of gastrin (one of the hormones responsible for gastric motility, meaning moving food through your digestive tract).

"Coffee can cause bowel movements because it contains acids that increase the hormone gastrin," says Andrew Boxer, M.D., a gastroenterologist based in New Jersey. "Gastrin causes involuntary muscle contractions in the stomach (peristalsis), which can get the bowels moving." This effect on the colon is well known, and some doctors recommend it to patients after colorectal surgery to get their bowel movement going, per a 2022 article from the International Journal of Colorectal Disease.

It Stimulates Cholecystokinin Levels

“Caffeine increases gastrointestinal hormones such as CCK (cholecystokinin), gastrin and motilin, which can increase the motility of the intestines and help with smooth muscle contraction,” says Boxer.

Cholecystokinin also increases bile production in the small intestine to push waste through faster, per StatPearls. If you have more coffee than usual, the higher amount of cholecystokinin could make a bowel movement happen more rapidly.

Does the Time of Day You Drink It Matter?

The time of day you drink coffee matters because your digestive system is more sensitive at certain times. The gastrointestinal system has elevated activity in the morning as it shifts from nighttime circadian rhythms to alertness, per a 2020 study published in the Journal of Clinical Gastroenterology. Drinking coffee while your stomach is more active may result in faster bowel movements.

Does the Type of Coffee Make a Difference?

The type of coffee you drink could make a difference in your bowel movements. These are some of the influencing factors you should consider before brewing your next cup.

Regular vs. Decaf

Though caffeine isn’t the only component that increases the urge to poop, it’s definitely one of the factors. "Caffeine stimulates the muscles in the digestive system, including the colon, which can increase the movement of stool through the intestines and result in more frequent bowel movements," says Danielle Kelvas, M.D.

As a reference, a standard cup of coffee contains 80 to 100 milligrams of caffeine, per the Food and Drug Administration. Depending on your health conditions and caffeine tolerance, your body may be more or less sensitive to that amount.

On the flip side, decaf coffee has little to no caffeine. And while it may not have the same effects on your bowels, some research has found that decaf might also help you poop, per the 2022 narrative review mentioned above. Try both to see the difference in your symptoms and make the best decision for your daily diet.

Hot vs. Iced

Hot coffee has caffeine and a standard brew strength. Iced coffee requires soaking grounds to extract a concentrated brew strength, resulting in extra-strong java. The intensified coffee may spike your hormone production more directly and cause colon contractions that lead to bowel movements.

Is It OK to Rely on Coffee for Pooping?

Coffee makes you poop, so can you rely on it for pooping when you're constipated? After all, 16% of adults in the U.S. experience symptoms of constipation, per the National Institute of Diabetes and Digestive and Kidney Diseases. Here are a few things to consider.

Precautions to Consider

If you're already sensitive to coffee poops, drinking more java may only result in uncomfortable side effects like cramping, diarrhea or gas. It may also introduce too much caffeine into your system, making sleeping harder and increasing the risk of experiencing other caffeine-related symptoms such as jitters and heart racing.

Excessive caffeine intake also affects your blood pressure. It enters the bloodstream and causes vasoconstriction, per a 2019 study in Nutrition Research Reviews. Living with consistently high blood pressure could make chronic heart conditions more likely, especially if you have other risk factors, such as family history. Additionally, caffeine should be limited in pregnancy and breastfeeding.

Frequently Asked Questions

Is coffee a laxative?

Coffee may act as a laxative because it may increase your digestive motility by stimulating the production of hormones involved in this process. The higher stomach acid production and longer half-life in caffeine can cause effects after you finish your morning cup.

Are there ways to stop coffee from making you poop?

There are a few ways to reduce the effect of coffee from making you poop. You could make a weaker brew to drink less potent java or drink only decaf. If you need the caffeine, avoid adding milk to your coffee. The lactose in milk could increase the urge to poop in some people. Additionally, some non-nutritive sweeteners might increase the pooping effect.

How long does it take for coffee to make you poop?

How long it takes for coffee to increase the urge to poop may vary from person to person. However, some research suggests that digestive contractions may start within four minutes of drinking coffee.

Can you drink coffee on an empty stomach?

You can drink coffee on an empty stomach, but it may lead to irritation and pooping due to the direct exposure to your stomach lining.

The Bottom Line

Coffee causes numerous biological reactions after your first sip in the morning. Not only may it help you wake up, but it can also help you poop. This is because coffee, caffeinated or decaf, increases the production of digestive hormones and gut movements.

Changing how you drink it could mitigate your bowel movements. Those changes will depend on your personal preferences. See if you enjoy coffee cold, hot or in various recipes to enjoy it more often without triggering your digestive system.

Read the original article on Eating Well.