I've noticed that whenever I drink too much coffee, I start having diarrhea. Can too many cups of coffee cause diarrhea?
Yes, coffee is known to stimulate bowel movements in some people. It could also be milk in the coffee too.
Yes, caffeine is a drug, legal, but a drug. All drugs in excess can harm you. Like all uppers, caffeine, which is a xanthine, increases your blood pressure, increases your heart rate, all secretion, diarrhea, etc.