Contains Fipronil, the same active ingredient as FRONTLINE® Plus for Dogs. Fast-acting, long-lasting and waterproof. Dual Action: Fipronil with (S)-methoprene insect growth regulator effectively breaks the flea life cycle. Kills fleas, ticks, chewing lice, flea eggs, flea larvae and prevents the development of flea pupae. Kills ticks including those that may transmit Lyme disease. Kills brown dog ticks, American dog ticks, lone star ticks, and deer ticks for up to one month. Rapid elimination of chewing lice infestation.