We’re going to need photos to answer this accurately.

I think it’s because the coffee is hot, and if you’re ready to go, the coffee just warms things up and makes it all ready. You will have the same effect with tea or hot soup.

I don’t know the cause, but I’ve used coffee to induce defecation (not diarrhea, thankfully) since my days running high school track and cross country. We long distance runners had a ritual when arriving at the venue, of finding coffee and then heading for the bathroom stalls.

I’m convinced the popularity of coffee is connected to its defecatory properties, even if those who drink it regularly wouldn’t admit that. But I guess it affects some people more strongly. (I’m a tea drinker myself).

I drink 8 cups of coffee everyday and didn’t have that effect until recently?
I discovered that I had been making the coffee too strong than usual and now have corrected it.
I make a pot of eight cups in the morning and throughout the day I have a cup.
Unusually by 7pm all the coffee is gone for the day with no effects…my solution is to make the coffee weaker and or change brands?
I usually make “Irish Cream” coffee but switched to “French Vanilla”, no effect until I put too much into the coffee filter. Corrected now and all better.

Maybe you are lactose intolerant?

It is probably the caffeine doing it. Many laxatives have caffeine in them. Your body is probably sensitive to it.

@seawulf575: I would agree with the “caffeine theory” except that Coca Cola, Pepsi, Dr. Pepper, ice coffee and ice tea don’t have the same effects, which is why I go with the “hot theory” that I detailed above.

@jca2 I agree with most of your post except for Dr. Pepper. I love the stuff but one can of it and I’m heading to a bath room. PS didn’t know they had that up north.

The reason is a combination of two things: coffee is a diuretic (remember poop is 75 % water) and also Caffeine stimulates the colonic muscles, which causes bowel movement contractions that are very similar to the ones from eating a meal.

Add in dairy, and sugar, (or if you add fake sugar, sorbitol,) and you are just adding more laxatives to the mix.

@Nomore_lockout: My aunt’s husband (long deceased) worked for Pepsi, and they lived in Florida. In Florida, the equivalent of Dr. Pepper was Mr. Pibs. I like Dr. Pepper a lot – always diet.

Look at your question. Seeing the spelling of diarrhea gives me a vowel movement.

I can smell coffee brewing and head to the restroom. Probably the diuretic as well as psych component.

@ragingloli What is it about coffee that causes immediate diarrhoea?

If,‘It does not even go through the digestive system’, you’re probably ingesting it the wrong way.

If you have chronic diarrhoea consult a doctor.

Coffee definitely helps me to go more easily, and speeds things along, but I have never experienced diarrhea after drinking coffee, even after drinking multiple cups. I’m guessing you must be sensitive to the caffeine.

You better go back and review anatomy.