I was away for most of the weekend and now my other cat Storm has a bald spot on his head. He also has one where I applied the advantage. I think that both he and Sunny had allergic reactions to the shampoo and/or advantage. Poor kitties. Luckliy the spots don't look like ringworm because there aren't any white flakes. I think I'm going to be buying a black light to keep on hand for future use.