I have two dogs, They have fleas, I thought as soon as the cold weather came in the little suckers would die, But no My poor dogs, Their young and always scratching which drives me crazy!! There Large dogs but I found to give both the dogs and I relief is Benadryl 1 to 2 Tabs (depending on the size of dog) It relieves itching and knocks them out so they dont keep scratching. Hope this helps someone and their pets. I dont know how it works for Cats though.