It contains nitenpyram, the same veterinarian-recommended active ingredient found in Capstar® (nitenpyram).* Capguard is an oral flea control medication available over-the-counter to consumers like you. This easy-to-dose tablet begins working within 30 minutes. It cuts out the mess and does exactly what you need it to do: kills adult fleas fast! Give this effective and hassle-free product a try!