Kill fleas fast! CapAction begins working within 30 minutes to kill fleas on your pet. In studies, CapAction achieved greater than 90% effectiveness against adult fleas on dogs within 4 hours and cats within 6 hours. Remove the hassle of messy treatments with this easy to give flea control medication for both dogs and cats. CapAction is taken orally and provides protection that doesn't wash off of your pet. Each CapAction tablet contans the active ingredient called Nitenpryam which is effective eliminating fleas in dogs and puppies. In fact, CapAction contains the same active ingredients as CapStar! CapAction Tablets do not have an effect on fleas in the pet's environment. You may need to treat more than one time because immature fleas in and around the home will continue to develop into adults that can reinfest your pet.