I had my doubts that a product so inexpensive would work BUT I have been using this for a couple of months on my cats and dogs. We had to bomb our house at the end of summer because of fleas. NOW, the pets are not scratching anymore; fleas aren't a problem in the house and even our diva cat, Ohana, who actually had sores from scratching is healing up nicely now. I'm grateful because I am actually taking care of pets for others as well as mine and it gets expensive. We want to care for them but it's becoming increasingly too expensive. Thank you, Petfriendly!!