In the past decade, the focus of flea population management has shifted from environmental treatment to on-animal suppression. Using the animal as “bait” has the advantage that all pre-reproductive fleas must be exposed to the host before mating, as they acquire their first blood meal. Host applications include imidacloprid, fipronil, selamectin, lufenuron, and nitenpyram. Fipronil has the additional benefit of acaricidal properties, making it effective against ticks and mites, as well. Because on-animal products increase human and animal exposure, products formulated for host use must display extremely low mammalian toxicity. Fleas can live on wild animals such as opossums, raccoons, foxes, skunks, etc., so environmental suppression remains an integral component of overall flea management. Both adulticides and insect growth regulators include products targeted to areas where immature flea development occurs.