Originally Posted by FluffyCatLover

I have treated for Giardia so know it's not that and have sent off fecal samples which are completely clear. He is a very big boy, very active and healthy with no vomiting whatsoever or any other nasty symptoms.

He has been on Hills I/D which started to make an improvement but is now making no difference whatsoever. I don't think it is IBS or IBD as his sister had it too and another cat we brought in had it as well although the 2 girls are much improved now thankfully. Again, all of them tested clear in fecal samples. Only thing that was slightly raised was their clostridium levels but the vet didn't think they were high enough to be causing the problems.