Anonymous

Because Coca-Cola contains phosphoric acid! Phosphoric acid mixed with stomach acid causes foaming in the intestines and the result is straight to the bathroom for a lot of people!

Anonymous

Because coke is extremely acidic. It can actually take the rust of off a car battery terminal. So imagine what that is doing to the lining in your stomach. This is not a joke. I actually have done just that. Take the rust of off a terminal

Anonymous

It may be due to the caffeine in Coke (which has more than most colas, I think.) Caffeine stimulates the abdominal muscles and can trigger diarrhea, but it's usually very short lived.

Anonymous

Lot of acid in Coke. Some people's stomach react to the acid. Just as there are some people who are lactose intolerant or allergy to strawberries or can not eat glutton, so there are people who can not drink Coke.