My Dog Has Diarrhea?

My dog has diahrrea. He's had it before and responded to antibiotics and everything was "coming out" fine, but it started out again, I got antibiotics again from the vet and it's been four days and he still has loose stools.

Sorry to talk about something so non-pleasant, but I'm resorting to taking him off solid foods as that is what my dog book suggested. Anybody out there have any good ideas? My vet said he has colitis and it's awfully hard to stop the cycle. And don't suggest cottage cheese as I'm a non-dairy eater and I come from the school of thought that dairy encourages diahrrea, so I wouldn't want to give that to my dog.

Margie