My cat has flea allergies, so he has scabs all over his body from reactions. He also has been licking himself bald in spots because his skin is so irritated. We were told by to use a different brand of flea medicine each month. This seems to help my cat better than the brand used last month. I think it helps a lot that there are natural ingredients. The only problem with this medicine is that it makes your cat smell really weird, and very strong! You can smell it almost all around the house!