3 Doses Kills Fleas, Flea Eggs & Larvae and Chewing Lice Fast Acting Long-Lasting Waterproof Use Only on Dogs and Puppies weighing 23-44 lbs and 8 weeks or older Kills all stages of ticks, including those that may transmit Lyme disease. Aids in control of sarcoptic mange mite infestations. PetAction Plus for Dogs contains the active ingredients fipronil and (S)-methoprene that effectively kills and controls fleas, ticks, and chewing lice. PetAction Plus for Dogs is fast-acting, long-lasting, waterproof, and easy to use. PetAction Plus for Dogs remains effective even after bathing, water immersion, or exposure to sunlight. PetAction Plus for Dogs can also be used on breeding, pregnant and lactating female dogs.