Contains fipronil, a special ingredient that spreads by way of your pet"s body oils to nullify a parasite"s nervous system, causing paralysis and death. * Kills fleas before they have the chance to lay eggs - thus breaking the flea life cycle. * Generally kills fleas before they bite, thus reducing the risk of sickness, allergies and disease transmission. * In pre-measured, child proof, easy-to-use applicator tubes. * Stain and odor free.