Help protect your kitty from pests with Frontline Plus Flea & Tick Treatment for Cats & Kittens. This flea and tick treatment is specially formulated to kill adult fleas, flea eggs, flea larvae, chewing lice and ticks, including ticks that may transmit Lyme disease. It’s made with two active ingredients—fipronil and (S)-methoprene—to help disrupt the flea life cycle and prevent future infestations. Each fast-acting topical application offers 30 days of waterproof protection. FRONTLINE Plus for Cats is purr-fect for cats and kittens eight weeks or older weighing over 1.5 pounds.