I tried this for over six weeks on several dogs and none of them showed any improvement. One of them started itching terrible. I wouldn't spend the money on this product.

I have added I-Stain to my poodles dry food diet and it works! Been using for over a year now and no more painful crusty eyes that need constant clipping and wiping with eye wipes! Since I have two poodles who can both eat the same dry food, I pre-mix a Rubbermaid larger square container and mix well with a spoon to cut down on mixing and keep it on top of the dog food inside my 40 lb. sealed food bin in the kitchen. That way I only have to mix it up every three to four bowlfuls since I open feed. Make sure to wash out your stainless bowl after each filling, as it's so fine it coats the dry bites well and and will leave a reside from the mixing w/ food. Just rinse & scrub in hot water, dry & fill. Makes taking care of your beloved four legged family members easy! Also, wash the storage pre-mix tub each time it's empty. I love time savers, plus my dogs get filtered water & ice daily during these warmer days to keep bacteria away!

My kitty was allergic to this product, I had to take her off it immediately. She started over-grooming her belly, and nearly licked all the fur off! My vet put her on steroids and she cleared up after a few weeks (plus removing her from the I-Stain product). Maybe your cat will not be allergic, but mine was. She was not on it long enought to determine if it helped with the eye stains or not.