Caught something when I was on holiday in Tunisia with a couple of mates 5 years ago. Spent pretty much the entire holiday on the toilet - I’m sure more came out that week than ever went in.
Went to the doctor in the resort who gave me an injection into my arse cheek, some 1000mg paracetamol and these awful things:
The highlight of the entire ordeal was shitting my pants as I was throwing up (on my birthday, too) - It goes without saying the whole saga has become a long running joke, that I will never be allowed to forget and my best man of course brought it up in his speech at my wedding 
Wasn’t right for ages after I got home either - Settled down within a week or so to the point where I was at least able to eat/drink and keep it inside me, but my guts were a state for 6 weeks or so.
Wish I’d gone to the doctor after getting home just to find out what was actually wrong with me.