FDA approved for use in dogs and cats. Available by prescription and over the counter.Once the female flea ingests blood from a pet treated with lufenuron, 96% of egg development from fleas on cats and 99% of egg development from fleas on dogs is stopped. This helps prevent a continual flea problem. Lufenuron does not kill the adult flea and does not stop the flea from biting and causing flea allergy dermatitis. Lufenuron is stored in the body fat and released into the bloodstream over the course of a month. Flea eggs laid prior to treating the pet may take several months to hatch. Lufenuron will not be effective until these fleas start to lay eggs. Therefore it may take several months to see the product's effectiveness. If quicker results are needed, use our Nitenpyram Capsules