Parastar contains fipronil, an insecticide that targets the nervous system of pests. The topical treatment is applied to the skin and spreads into the hair follicle. It will then kill adult fleas before they lay eggs, ticks (brown dog ticks, deer ticks, American dog ticks, lone star ticks) that may transmit Lyme disease and Rocky Mountain spotted fever, and chewing lice. In addition, it also controls mites that may cause sarcoptic mange. Parastar is a one spot, topical flea, tick, mite and chewing lice treatment developed for dogs and puppies 8 weeks of age and older. The waterproof, topical solution comes in an easy to use applicator that is applied to a single spot and provides flea and tick protection for one full month. Gentle enough for use on puppies eight weeks of age or older.