When I was going through the diarrhea mess with Moxie and Decker I had to leave them at the vet for a couple of days to let her get it under control. My vet fed them nothing but yogurt (she went to a health food store to get one with several active cultures) for the first day and she saw a big improvement from that. She continued with the yogurt but started adding some prescription canned dog food the second day.

I wonder if Starr might need to let his intestines heal a bit, that was what the vet said the kittens needed when she fed them only yogurt. It did seem to work.

Poor Starr, I hope you and the vet can get to the bottom of it soon.