Any coffee lover will tell you the beverage is a godsend. The bean juice is an easy pick-me-up on sleepy mornings and energy-drained afternoons. It instantly warms your body on chilly winter days. And the ritualistic process of brewing a pot is inherently calming.
So, Why Does Coffee Make You Poop?
Although the need to go no. 2 after sipping on coffee is seemingly common, there isn't much research investigating why, exactly, the drink may cause this side effect, says Dr. Schnoll-Sussman. Still, gastroenterologists do have a few theories as to what's happening.
For one, eating or drinking anything — coffee included — stimulates the gastrocolic reflex, a physiological reflex that controls the motility (re: muscle contraction) of the lower gastrointestinal tract after a meal, says Greg S. Cohen, M.D., a gastroenterologist and a clinical associate professor of medicine at Northwestern University. “When the stomach senses incoming food or drink, there’s some nerve communication and some chemical-hormonal communication between it [and the colon],” he explains. “It sends a signal out to the colon, which stimulates the colon to contract, and that makes you feel like you have to go to the bathroom sometimes.”
The caffeine in coffee may also play a role in triggering that urge to poop. In a 1998 study, researchers found that both caffeinated and decaf coffee increased colonic motor activity (i.e. colon contractions), but the caffeinated variety had a 23 percent stronger impact than decaf coffee and a 60 percent stronger impact than hot water alone. “It does seem that caffeinated products could be more of a stimulant for people,” says Dr. Schnoll-Sussman. “But remember, decaffeinated doesn’t mean no caffeine — decaffeinated means that there’s less caffeine.” (FTR, the decaffeination process removes about 97 percent of caffeine from coffee beans, according to the National Coffee Association.)
Besides those twopotential mechanisms, the reason why coffee makes you poop remains a mystery. "Eating or drinking anything has the ability to stimulate colon contractions and the feeling that you have to go to the bathroom, but then there is legitimately something extra going on in coffee that stimulates that more powerfully," says Dr. Cohen. "There appears to be some sort of unknown compound or compounds in coffee that have the ability to stimulate the gastrocolic reflex more potently than any other warm drink — and we really don't know what that is."
What’s more, certain coffee add-ins can further contribute to those GI effects. Pouring milk or cream into your coffee if you’re sensitive to lactose can stimulate those colon contractions, and swirling in artificial sweeteners, such as sorbitol and xylitol (which are known to have laxative effects), can also trigger the need to hit the porcelain throne, too, says Dr. Cohen. “I think those are probably minor factors, but it can all add up,” he adds.
How Quickly Can Coffee Make You Poop?
When you gulp down a beverage, whether it be coffee or water, it only takes a few seconds for the fluid to move through the esophagus and into the stomach, says Dr. Schnoll-Sussman. Your stomach typically empties all of its contents in just 30 minutes. But with coffee specifically, you might start experiencing colonic contractions within a few minutes and feel the urge to have a bowel movement at that point or within the next half an hour, she explains.
And one study, albeit small in size, backs this up: The majority of participants who drank black, unsweetened coffee experienced increased rectosigmoid motility (muscle contractions in the last part of the sigmoid colon and the beginning of the rectum) within four minutes after drinking both regular and decaf coffee, and the increase lasted at least half an hour. In comparison, none of the participants had increased motility after drinking hot water.
Who Feels the Need to Poop After Drinking Coffee?
While anyone may experience coffee-induced poos, some folks may be more likely to deal with the side effect. For example, people who have irritable bowel syndrome often have a stronger colonic response to gastrocolic reflex, says Dr. Cohen, and, in general, they may experience a strong urge to poop after consuming any food or beverage, according to research published by the National Center for Biotechnology Information. As such, coffee could amplify the need to hit up the restroom immediately after swigging a cup of Joe in these individuals, he explains. Similarly, people with untreated or poorly treated celiac disease (some of whom may experience IBS symptoms), Crohn’s Disease (a chronic inflammatory condition of the gastrointestinal tract), or ulcerative colitis (another chronic inflammatory condition that affects only the colon and rectum) may be more sensitive to the gut effects of coffee, says Dr. Cohen.
People following an intermittent fasting diet could also be more likely to feel coffee’s GI effects, adds Dr. Schnoll-Sussman. Since these individuals are eating only during limited time periods, the food they do consume may be sitting still in their system for hours at a time, as “they’re not grazing, stimulating the intestine, and showing fiber to the intestine all throughout the day,” she explains. As a result, drinking coffee after not eating for 16-ish hours could “rev up their system” and cause them to have a bowel movement, she says. (FTR, this effect hasn’t been studied, and Dr. Schnoll-Sussman notes that this idea is purely a hypothesis.)
Can You Use Coffee to Relieve Constipation?
If sipping on a piping hot mug of java each day helps keep you regular, it's okay to keep doing so, says Dr. Schnoll-Sussman. "For those who enjoy their cup of coffee in the morning, and it definitely helps them then make that trip to the loo, they should continue to enjoy that," she adds.
That said, coffee should not be your go-to remedy for chronic constipation, says Dr. Schnoll-Sussman. “If you are someone that has a new change in bowel habits, new constipation that you’ve never had before, belly pain, any kind of weight loss, blood in the stool — things that seem different to you — then you should not be just turning to coffee to fix to it,” she explains. “You should be seen by a physician to make sure there’s nothing else that’s going on.” Blockages in the colon or rectum, pelvic muscle dysfunction, and hormonal conditions such as diabetes, hyperparathyroidism, and hypothyroidism can all lead to chronic constipation, according to the Mayo Clinic, and chugging a cup of coffee isn’t going to treat these root causes.
What to Do If Coffee Makes You Poop
When you're on a first date at a local café or you're working in the office, you may want to desperately avoid the smelly side effect of coffee. Unfortunately, your best (and safest) bet to prevent a poop after drinking coffee is to avoid the beverage altogether, says Dr. Cohen. "It makes a lot more sense to withdraw the offending agent that's causing the problem, rather than adding another medication or another substance on top of coffee to counteract those effects," he explains. "So I wouldn't advocate for adding any supplement or medication to [do so]." If your coffee habit's GI effects get to the point where it's interfering with your life, consider talking over your symptoms with your primary care doctor or a gastroenterologist, he suggests.
You can also use some free time to experiment with coffee and develop a better understanding of how it affects you, says Dr. Schnoll-Sussman. On a weekend morning, drink a cup of your usual coffee, then take note of how long it takes for you to need to drop a deuce, she suggests. If you find out you're rushing to the bathroom about 30 minutes after you take your first sip, you can use that info to plan out your days and avoid a public poo; you might wake up earlier to avoid going no. 2 in your shared office restroom or drink your afternoon Joe an hour later so you don't feel the urge while you're driving home. All in all, "you have to figure out your own internal clock," says Dr. Schnoll-Sussman. "You have to figure out how your body responds to coffee, which, in some respect, is a little bit like a medicine."
