When my cat was diagnosed with inflammatory-bowel disease and pancreatitis, I tried this. It actually helped for a while, when nothing else would. And when my cat refused to eat, sprinkling this on his food enticed his appetite. Now that his condition has progressed to cancer, there is nothing that can help. I assume that cats, like people need to keep a good balance of pro-biotics in their digestive system and that this is important for immunity. Anyone whose cat is taking antibiotics (which are over-prescribed) should definitely use this product to get the digestive system back to normal.