My cat Gato has lost alot of weight, vet took blood test and said looks like IBS, since then the vet has tried different steriod injections and all different prescription food diets and nothing is working, he has messy stools (has gone on the carpet a number of times) he acts fine, eats and is friendly just the weight loss (from 12 pounds to 8.5 pounds) now we are trying Tylan 2x day, no change yet. Vet said could do a biopsy but what would that show? plus he said it is very invasive and expensive. I am thinking of getting some probiotics to try. Anyone have any ideas? I don't think he has IBS, none of the things we tried made a difference.