The People's Perspective on Medicine

Why Does Coffee Make You Poop With Regularity?

Have you ever had the experience of drinking a cup of coffee and then having to head for the bathroom pronto? Can coffee make you poop or is it a myth? Find out!

OK, we admit that this is not one of the great medical mysteries of all time. It is intriguing, though. You might think that researchers have far more important things to do than try to figure out can coffee make you poop, and if so, why? It turns out that they have been struggling over this coffee conundrum for years. There may now be a plausible explanation. It was presented a prestigious meeting of gastroenterologists.

Coffee Makes Him Go to the Bathroom:

Q. I have found that my body reacts in a very predictable manner to my morning cup of coffee. Usually within 5 to 10 minutes I have to go to the bathroom. Is it the caffeine or something else in coffee that stimulates the bowels?

Does the Caffeine in Coffee Make You Poop?

A. You are not the first person to notice this effect. We used to think the caffeine was responsible, but scientists have shown that both regular and decaf coffee stimulate colon activity (Gut, April 1, 1990).  Caffeinated coffee does seem to have a stronger effect, however (European Journal of Gastroenterology & Hepatology, Feb. 1998). 

How Many People Are “Moved” by Coffee?

The small study in the journal Gut cited above reported that 29 percent of the volunteers in their study claimed “that coffee induced a desire to defecate.” That could be right, but we would need to see much larger numbers to find that stat convincing. There were only 99 volunteers willing to participate in that research. The actual number could be substantially higher for all we know.

Does the Acid in Coffee Make You Poop?

Some scientists have attributed the laxative effect of coffee (regular or decaf) to its acid content. Chlorogenic acid can stimulate acid production in the stomach. The theory goes that this effect in turn triggers intestinal movements. So far, though, the data are not convincing.

Will the Magnesium in Coffee Make You Poop?

Some people suggest that coffee is high in the mineral magnesium. Everyone knows that magnesium has a laxative action. Just think Milk of Magnesia (magnesium hydroxide). A 2 oz cup of espresso has almost 50 mg of magnesium. But a regular cup of coffee has only about 7 mg of magnesium. That is not enough to get things moving.

What Really Makes Coffee Send You to the Bathroom?

Scientists have tested coffee in rats and found that both decaf and high-test increase the contraction power of intestinal muscle contractions. There are purported to be over 1000 different chemicals in coffee; hence the complex flavors and unique aroma. The researchers at the University of Texas, Galveston, did not identify which specific chemicals in coffee stimulate muscle movements within the digestive tract.

Coffee and the Microbiome:

The coffee treatments also changed the composition of the rats’ gut microbes, though no one is quite certain what that means for digestive health. One possible application of the coffee discovery is in the hospital, of all places.

When patients undergo abdominal surgery, they frequently develop something called post-operative constipation. When surgeons handle your intestines, the tissues tend to revolt by not resuming normal contractions for awhile. There are also the anesthetics, muscle relaxers, pain meds and the immobility of recovery. If coffee helps get the intestinal tract moving again, perhaps someday doctors will prescribe a cup of coffee in the days following abdominal surgery.

The investigators reported their research at a conference, Digestive Disease Week (DDW) 2019.

Share your own experience with coffee and trips to the bathroom in the comment section.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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My name-sake aunt always drank a cup of hot water while everyone else had coffee or tea, as she did not like coffee and tea. And that worked for her.

Coffee has kept me regular for years, though I don’t know why. Recently I was in the hospital for open-heart surgery. Every day in the hospital the nurses plied me with stool softeners which, unfortunately, failed to move me. I laughingly asked for coffee one day, saying it would surely work, and one nurse was kind enough to slip me a small cup. It did its job! I spent another 18 days in the hospital where cajoling for more coffee did no good. Neither did double the amount of stool softeners relieve me. Going home was such a relief–in all ways.

For me it’s eating pancakes or waffles….thinking it must be the syrup.

In my opinion, I believe it’s the “heated water” that really causes the digestive movement. I suspect any heated liquid would do the same, especially after overnight bowel inactivity.

I’m one who experiences the drink coffee/have to poop soon, reliably every day.

Has anyone suggested or looked into the effect of hot versus cold coffee? Or even just hot water/hot tea?

Ann B.

My late father, for all of the part of his 78 years that I knew him, always began the day with a 10 to 12-ounce glass of very warm water. (He never drank tea or coffee) He never suffered from constipation, and issue was settle soon after drinking the water. I have same result -any time of day-from my first cup of coffee of tea. Coffee seems to work better, perhaps because I consume it hotter and faster, and in a 12-ounce rather than eight- ounce quantity.

I am a professional university physiologist, and have long thought there were several factors at play. One, reflexive or almost reflexive reaction to this volume hot liquid in the stomach. Two, this is reinfornced by becoming a learned response (to the point that I have to have my first cup of coffee before leaving my home or hotel room, even when going out to breakfast!). Thirdly, this fluid consumption helps combat dehydration, a major cause of constipation. (I once worked with a gastroenterologist who started his
treatment plan for chronic constipation with an order for six or more glasses of water a day, and it usually worked!)

Any hot liquid in the morning does this…hot chocolate, hot broth, even hot water. I think it’s just the hot liquid that has “trained” my gut to go into action in the morning…after all, I’ve been training it this way for over 60 years.

I drink two cups of water when I get up in the morning and the eat a banana several minutes afterwards. I have the same results as described with the coffee. I then take a walks and drink two cups of coffee on my return. No additional bathroom visit. Maybe it is just the liquid??

For 5 decades I have been drinking coffee with caffeine as soon as I get up in the morning. 15 minutes later I am, without fail, defecating. It’s feels great to let that load go, so regularly!

I get the same effect from my habit of drinking 2 cups of tea (various blends) every morning. I think it’s the warm water.

Do you have a study: morning coffee vs cup of hot water. I believe it is the hot liquid that cause the bowel movement.

I get the same results with my morning coffee, but it could be just the relaxation effect because I sit and drink it slowly while I read and wake up. I also have to “go” if I sit at the piano and play a while, or if I call and talk to my mother on the phone. The opposite happens when I’m on vacation….can’t always find a relaxing time to go. When I was a teenager before I drank coffee the same thing used to happen after drinking a Dr. Pepper. So the rumor back then was that Dr. Pepper had prune juice in it.

I also find that quickly drinking a large ice cold glass of water gets things moving.

I have not had that effect when I drink Coffee. All coffee does to me is I pee a lot.

RE: Coffee making you poop: I get the same reaction by drinking a glass of ice cold water first thing in the morning. Immediate results! The key here is to have ice and very cold water. Works every time.

My theory is that most coffee contains pesticides. The body is trying to get the poison out of it.
I have always been bothered by the smell of coffee. Unless it is grown organically, I believe it is the pesticides.

Whenever I am constipated, I drink a cup of hot strong coffee and it cleans me out .With no side effects. I feel great after. I highly recommend it as a laxative, especially dark roast. Does the trick for me. And I love their coffee which is an added bonus.

Whenever I am constipated, I drink a cup of hot strong coffee and it cleans me out like Draino. With no side effects. I feel great after. I highly recommend it as a laxative, especially Starbucks Pike roast. Does the trick for me. And I love their coffee which is an added bonus.

While magnesium may be part of the factor I would think that the stimulant effect of coffee has a lot to do with getting things to move down the line. Coffee definitely changes my bathroom habits as does other food products. No surprises here.

I get the same effect from the chocolate I eat first thing in the morning. I make it myself from coconut oil, unsweetened cocoa powder, and a bit of honey. I think cocoa powder is also high in magnesium.

Coffee first thing in the morning would stimulate the gastrocolic reflex* like any meal would, but has the boost of being liquid, hot, and containing a rapidly absorbed stimulant (caffeine). The answer is: multifactorial. Have a cup of coffee and enjoy!

* gastrocolic reflex – eating/swallowing and putting food in the stomach stimulates entire GI tract activity, notably, the distal colon to move contents down for elimination.

I can vouch after two morning cups I feel Beethoven’s 9th -1st movement building up and then voila its done. Sometimes there is a 2nd. Whatever it is I think part of it has to do with loosening up with its diuretic effect. I could be wrong but coffee has many benefits including saving money on laxative.

I rarely drink caffeinated coffee while out & about, as it has an “effect”. Best to stick with decaff which doesn’t bother me.

After a 2-week trip in Europe without decaf coffee, I was really uncomfortably constipated. 20 minutes after a cup of decaf in the airline lounge, I finally got relief! Whatever the reason it certainly works for me!

Both my daughter and I have the same effect with drinking morning coffee. Honestly, I like the response.

As a young nurse I used to have patients who insisted on a cup of hot water early in the AM for the same purpose. Whatever works!

Coffee works for me sometimes. I usually have two cups in the morning. Some days I have to go right away. I have never been one of those people who poop on a daily basis, or at the same time everyday. I go when the bowels says it’s time to empty me.

Had chronic constipation as a child. When I began drinking coffee, it disappeared.

They do all these tests to see if this theory holds water??? There are so many people who will tell you that coffee is a natural laxative. Guess they are trying to find out how it works. They also said that both caffeinated and decaf coffee would do the trick. But when I drink decaffeinated coffee it will not have that effect one me.It is only the caffeine that will work. I have experimented so many time, as I try not to drink caffeine coffee every day. But it only works on the days when I have caffeinated coffee.

I am beginning to think it is not the caffeine, as when I drink tea with caffeine it does not give me the same results. So I guess they need more tests to find out what ingredient in the coffee is the culprit.I just know that decaffeinated coffee does not do it to me.

I’m definitely one who can partly attribute my regularity to that morning cup of Joe. Interestingly, I’ve experienced and read that coffee also stimulates the bladder in the same way.

I suspect everyone is over-thinking this stimulative effect. A glass of warm water upon waking up will have the same effect, at least for me it does. I try to have my bowl movement before taking my morning shower. I find that if I drink a glass of lukewarm water or eat something warm, I will feel the stimulation a short time later. Not 100% reliable as some days the effect comes too late or not at all, but the majority of days it works.

I have to have 2 coffees and 4 squares of 99% dark chocolate every morning at between 7 am and 8am to keep me regular . If i am missing one of these it does not happen , before i started this routine i had problems for 40+ years with constipation now always regular .

I had Gall Bladder surgery a few yrs ago and ever since then when I drink coffee it does seem to make me have to poop after I drink a cup. It also has this affect on my grown son.

I usually have to go a few hours after drinking coffee. I did not think it was the coffee as much as it being a warm liquid. I don’t like drinking hot water so I have not tried to prove this one way or another.

A cup of very warm water right from the hot water system so no work or needing to fix anything on getting up also does the same .Learned in college it starts your system and wakes it up . Has worked for 65 years . Bathroom cup size is alll that ‘s needed .

Absolutely Positive !!! The morning (strong) cup of coffee is sending me to the bathroom –(something like after 20-30 minutes ) i really enjoy the morning coffee (which is by the way my only coffee during the day ) and since i am tendencially constipated rather then diarrhea person i appreciate and enjoy also this for me benefficial “side effect”

This is something I can totally relate to. Every morning I turn on the coffee maker and like magic, my colon reacts positively. Sometimes just the smell of coffee brewing sends me to the bathroom. This only happens in the morning. I used to chalk it up to early movement after sleeping all night, but then I realized it never happens any other time of the day if I brew coffee. Guess I am not as unique as I thought. Been reading you and catching your shows on PBS for many many years. Keep up the good ethical work.

My husband has always said this works for him. Does nothing for me!

I do not experience this, it’s more like 2 to 3 hours after my first cup of coffee. My grandfather had some colon issue and a doctor and instructed him to drink warm water. So I’m thinking it maybe just the warm liquid that is affecting the intestinal movement and therefore the need for a bowl movement.

Once when I had severe constipation Dr sent me to Starbucks to get a super high test brew if double ‘something’. Effect was not dramatic for me but it was helpful.

Really prefer Peoples’ Pharmacy had a bit more class when choosing its verbiage, ie: “Poop” – really??????!!!!!!!!!!!!!!!!!

I think it’s just that it’s hot. Many years ago a friend of mine said her mom told her, “Every morning, drink your coffee and walk around, walk around, until you go.” So it’s been known as a way to get everything started for a loooooong time!!

It works like that for me occasionally but not very often. On the other hand, it affects my wife like that every day. Don’t get between her and the bathroom after her morning cup of coffee.

My mother always said she could solve her constipation with a cup of coffee in the morning. I find I can do the same. I’m normally a tea drinker, but when I haven’t had a bowel movement, a cup of coffee will take care of that.

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