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By Dan Wighton


Coffee goes straight through you. And usually, it takes whatever else you have in your stomach with it. But while scientists and coffee drinkers have known of this phenomenon for decades, there is still plenty we don’t understand about why a coffee makes you poo – only that it does.

What coffee does beyond your taste-buds
Coffee contains the natural compound chlorogenic acid, found in both green and roasted coffee.

It exists naturally in coffee, and inside the stomach, goes on to produce gastric acid. When extra gastric acid is produced, the stomach will push its contents out and into the intestines.

However, this is only part of the process, and doesn’t explain why coffee leads to such immediate evacuations of your internal organs.

The research has been further hampered as not everyone experiences the same phenomenon.

Only 30 per cent of people are affected by coffee in that way, meaning that even finding consistent test subjects was a challenge for scientists and researchers.

Who needs laxatives when we’ve got coffee?

Aside from chlorogenic acid, what else contributes to the coffee-poo connection?

When people think coffee, they think caffeine, so caffeine is often thrown up as a possible reason. But people don’t usually have the same response to other things that contain caffeine – like energy drinks, tea or cola.

Also, researchers have noted that even decaf has the same effect on a person’s stomach – meaning that caffeine is totally not the reason.

Other than caffeine, the average cup of coffee contains nearly 1000 different compounds, meaning that isolating the effects of each one – let alone the combined effects of each possible combination – is a time-consuming task.

In short, some of these chemicals combined them tells your internals, “It’s go time!” They push whatever is in your stomach out, and then trigger your body to release other chemicals which do the same thing.

So it’s a little more complicated than the old American saying a cup of joe makes you go.

The following video sheds a little more light on why coffee acts as a ‘quitting time bell’ to the Fred Flintstone in your stomach – at least to the extent that scientists know about yet – but just know that if your cup of Joe means you gotta go, you are not alone.



So although coffee is the reason, it is really a combination of coffee and your body doing the dirty work. In the 30 per cent of people whose bowels are affected by coffee – decaf or regular coffee – muscles in the lower tract of the colon really get to work.

The two main chemicals produced by your body after a cup are gastrin and cholecystokinin, which are otherwise produced to help push food through the body. For some reason – which science doesn’t really understand yet – coffee makes these guys work much harder.

And here’s something that might arm you with just enough knowledge to prepare yourself: The body’s response occurs within just four minutes of drinking the coffee.

Our tip – make sure you don’t find yourself caught short!

Research notes: Effect of coffee on distal colon function – published April 1990, in Gut, International Journal.



Dan Wighton is a Techly writer who likes to hide his alcoholism in an appreciation of fine booze (and likes to hide his alcohol around the house).

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