Within 24 hours, FRONTLINE Plus migrates all over the pet's body through a process called translocation. The sebaceous (oil) glands just beneath he skin act as a reservoir from which FRONTLINE Plus is slowly and continuously released onto the skin surface, where fleas and ticks come into contact with it. Fipronil works by attacking the nerve cells of fleas, resulting in their becoming disorientated and hyperactive before dying. (S)-methoprene interferes with egg production and hatching of fleas, as well as inhibiting larval development. Consequently, no more pupae are produced, and the flea life cycle is broken. FRONTLINE Plus protects your pet against most disease-causing ticks as well. When you use FRONTLINE Plus, the active ingredients are rapidly distributed through your cat's coat. In addition, FRONTLINE Plus is completely waterproof.