In fact, only 3 out of 10 people go to the bathroom after the morning cup of coffee.
Most people think that caffeine has a laxative effect, but studies have shown that this is not so, and the evidence for this is that some people have to go to the bathroom even when they drink decaffeinated coffee.
Therefore, scientists believe that the laxative effect of coffee is due to its acidic nature. Drinking coffee increases gastrin, which relaxes the muscles of the anal opening. At the same time, coffee increases the level of cholecystokinin, which releases enzymes bile and regulates bowel movements.
Coffee for its acid affects the digestion faster and therefore you have to run to the toilet in less than 4 minutes.
See video below where everything is explained: