Coffee, and anything with caffeine tends to completely destroy my insides now, and it only started happening after I got an extremely bad case of food poisoning about 3 months ago.
Before that, I was drinking 2 cups a day + energy drinks. Now, if I have anything apart from tea/chocolate/coke (i.e. low caffeine content) it upsets my bowels to the point of needing to go to the toilet within 5 minutes. It's crazy.
I've stopped caffeine in the last month and I've gotten a thousand times better.