After a few weeks of self-tests, I've discovered that when I drink coffee (with or without milk), the same day or nex day, I've diarrhea. Sometimes very loose and sometimes liquid.
Alot of people have to stop drinking coffee with IBS. It activates your gallbladder to put excess bile that will give you diarrhea ---- an empty stomach is usually worse.
My wife use to could only drink a half of cup before having diarrhea!!!
Harry