It’s not uncommon to feel your stomach gurgling shortly after drinking a cup of coffee. Coffee has laxative effects, and consuming it may cause an unexpected urge to go to the bathroom. So, if you haven’t eaten anything that could upset your gut yet feel the urge to hit the bathroom, chances are, you’re experiencing the laxative effects of caffeine.
Coffee can speed up bowel movements thanks in part to the caffeine present, which can trigger the gastrocolic reflex, causing stomach contractions. Coffee also prompts the secretion of gastrin, which promotes movement in the gut.
These laxative effects aren’t limited to hot coffee though; the same effects can be observed in cold coffees like iced coffee and cold brew, provided they contain caffeine. Let’s take a closer look at why these beverages might send you to the bathroom.
Why Does Coffee Make You Poop?

The post-coffee poop is a very prevalent phenomenon. In fact, one in every three coffee drinkers is likely to feel the need to go within minutes after drinking a cup of joe.
Scientists have spent a tremendous amount of time studying this effect, and they’ve come up with several causes:
Coffee’s Generally Consumed in the Morning
This theory suggests that because coffee’s generally consumed first thing in the morning, it triggers the gastrocolic reflex, which is responsible for causing intestinal contraction.
This reflex doesn’t just occur in the morning though, as it forms part of the digestive system. However, it’s more intense in the morning, because that’s when the gut is sensitive to any kind of ingestion.
Acid in the Gut
Coffee is an acidic beverage and drinking it increases the level of stomach acid. When the stomach produces an excessive amount of stomach acid, more bile is produced as well, and bile is known to cause diarrhea.
Caffeine Is the Culprit
Since caffeine is a stimulant, scientists believe that its stimulating effects stretch all the way down to the gut. Caffeine may be a factor, but not the main culprit, since decaf coffee has the same effects.
Secretion of Gastrin
Other researches suggest that coffee intake causes the body to release a hormone called gastrin, which is responsible for promoting movement in the gut.
How Does Caffeine Affect Your Colon?
The colon is the final part of the digestive system. Once food remains enter the colon, the colon drains it of water and readies it for excretion. It does so through contractions. The faster and more intense the colon contractions, the sooner you’ll need to go.
One thing typically happens to your colon when you decide to down that Jitter Juice: the rate of contraction speeds up, and with increased contractions, your colon produces loose stools. Depending on your body’s needs, this can be a good or a bad thing.
What Is Gastrin and How Does Coffee Affect It?
Gastrin is a hormone produced in the stomach acid lining. It’s an important component of the digestive system, because it primarily secretes hydrochloric acid, most commonly known as stomach acid or gastric acid. Gastric acid is essential in absorbing and digesting a wide variety of foods.
When certain activities take place in the stomach and digestive system, the stomach lining sends signals to the brain, prompting the secretion of gastrin. Gastrin secretion is triggered in response to the following:
- The stomach stretching during and after meals
- Increased pH level in the gut
- Unidentified elements in certain foods and beverages
After numerous studies, scientists observed that gastrin levels in the stomach tend to spike immediately after coffee ingestion. In short, coffee stimulates faster gastrin secretion. However, experts have yet to pinpoint the exact element of coffee that triggers this effect.
Why Does Decaf Make You Poop?
The idea that caffeine is behind the laxative effects of coffee is a misconception, since decaf coffee can have the same effects. Let’s get into the science behind it.
According to research, it’s not just the caffeine, but rather several factors that are at play here. Chlorogenic acids and N-alkanoyl-5-hydroxytryptamides are compounds found in both caffeinated and decaf coffee, and they also contribute to post-coffee poop.
These compounds can generate more stomach acid and as you now know, stomach acid speeds things up in the gut.
When it comes to decaf, experts also believe that it could also be a natural gastrocolic reflex since people tend to consume coffee, including decaf, when the stomach is most sensitive.
What About Iced Coffee?
Iced coffee can be made with a high-quality Instant coffee (on Amazon) or by brewing fresh pre-ground coffee beans (also on Amazon). People often opt for a large glass of iced coffee on hot days.
Iced coffee is a great alternative to your classic cup of hot joe. It offers coffee’s natural flavor profile without the heat. In addition, it doesn’t interfere with blood pressure. But what about the laxative effects?
Since iced coffee is primarily coffee, it will contain caffeine. As we discussed above, caffeine is a factor in the post-poop phenomenon. That said, drinking iced coffee will increase acid levels in your stomach and stimulate bowel movement.
In addition to the compounds found in coffee, iced coffee features another possible stool-inducing factor — its cold temperature. The coffee’s temperature also makes a difference.
Due to internal body temperature, the digestive system is accustomed to processing hot foods and beverages or foods prepared at room temperature. Cold foods, on the other hand, will trigger stomach contractions or even stomach cramps.
Should You Use Coffee to Relieve Constipation?

Since coffee has laxative properties that affect a wide range of coffee drinkers, it stands to reason that coffee may be used to relieve constipation. However, there’s more to it and we’ll discuss why health professionals warn against it.
Natural laxatives stimulate bowel movement by drawing water into the colon to soften it. These laxatives are called ‘osmosis laxatives.’ Another type of laxative exists also, namely the bulk laxative. It induces stool by increasing the weight of the stool in the colon.
One thing that they both have in common is that their effects are regulated, but they don’t trigger secretion or release of hormones or acids.
Conversely, coffee isn’t primarily a laxative, it’s a stimulant. It stimulates several other functions before making its way to the colon. What’s more, coffee tends to have more adverse effects on the body than laxatives.
Conclusion
Feeling the urge to head to the bathroom instantly after downing that cuppa Java is absolutely normal. There are a number of tricks you can implement to reduce or even avoid these effects.
Opting for a low acidic coffee is a good start. Cold brew should also do the trick. Steering clear of artificial sweeteners may also be helpful.