I take Metformin for my diabetes. One of the common side effects is chronic diarrhea, and I have that, in spades. It can be unpleasant, because I sometimes have only a few minutes between the first twinge of 'gotta go' and disaster. It's to the point where I won't eat if I know I'm going to be somewhere where I can't/don't want to use a bathroom.
But there is a bright spot! I had a colonoscopy a few weeks ago. I had heard horror stories of how awful the prep was: take the day off work, don't plan to do anything else, you'll be in the bathroom all day, etc. Aside from the fact that GoLytely is absolutely nasty to drink, I didn't notice anything odd. Until I got to the procedure; the doctor read my chart and said, 'Ah ha! You take Metformin! So you had no trouble at all with the prep!' Hm, apparently my everyday is what other people would consider horrible. But my insides were clean as a whistle (he noted on the report that 'the quality of the prep is excellent :-) ) so there's that.