With Capstar flea control for dogs, almost all your dog's adult fleas will be gone within four hours. Capstar flea treatment for dogs is a once a day flea medication approved for use in the treatment of flea infestations on dogs, puppies, cats and kittens 4 weeks of age or older and at least 2 pounds of body weight. Just one dose of Capstar flea control for dogs will kill the adult fleas on your pet. If your pet gets reinfested with fleas, you can safely give another dose of Capstar flea control as often as once per day.