Capstar is an oral tablet flea control formulated for use dogs and cats. It is very fast acting and kills fleas for 24 hours. One of the advantage of using Capstar Tabs flea control is that you do not have to worry about treatment being washed off with swimming or bathing. Capstar are developed to target the adult flea as part of the breaking the one of four main part of flea life cycle. The adult flea will be killed once it ingested the blood containing the active ingredient Nitenpyram. Capstar does not treat the environment outside the pet's body.