It seems to work better than other brands to keep fleas in check. I havent had a flea problem in years. That said, I have a small(ish) number of cats in a mostly clean and uncluttered house.
The flea problem Im battling at the moment is down the street where my retirement project is to bring a cat hoard under control. I dont even know how many catsin the last year Ive fixed and returned 16 cats and also removed 7 kittens. Theyre all living with their charming elderly humans in a decaying 12-bedroom cluttered mansion. Think Grey Gardens with cats.
My approach to the flea problem this year is to provide Advantage II for the indoor adult cats and Frontline spray for the kittens. Im also giving the elderly humans diatomaceous earth to sprinkle around. In a couple of weeks well do it again. I dont anticipate that this will eliminate the fleaswere hoping to just beat them back. The outdoor cats are too feral to do much with and they all have ticks and lice in addition to fleasthey get treated only when theyre trapped to be fixed.