Vetsupply: Advantage for cats is a monthly flea treatment. Applied topically the treatment kills 98-100% fleas within just 20 minutes. The topical solution affects re-infesting fleas within 3 to 5 minutes, kills re-infesting adult fleas within 1 hour and flea larvae in your cat?s surroundings within 20 minutes of contact with the active ingredient. It kills both adult fleas, and larvae found on the pet\'s body and in the surroundings.