I had looked at these before, just another flea collar. Well my Jake is a big shepherd, not easy to bathe (I have a torn rotator cuff). Bathing did not seem to help the endless scratching, may have made it worse. I tried three different flea drops, no relief. Within three days of putting on the SERESTA collar, the scratching had STOPPED. We have noticed that BOTH cats have stopped scratching as well - we do not treat the cats.