Within 24 hours FRONTLINE® Plus would have worked its way over your cat’s whole body by making use of the oil glands just beneath its skin, which can be seen as a kind of reservoir from which the active ingredients in FRONTLINE is released slowly and continuously onto the skin. The active ingredient fipronil, combines with (S)-methoprene, inhibiting insect growth. Once the fipronil attacks the creepy crawlies that infested your cat, they get disorientated and hyperactive, and then they die. Flea control lasts for 30 days. FRONTLINE® Plus also protects your cat against most disease-causing ticks. Apply frequently – once a month – for continuous protection.