ZoGuard Plus for Cats, comparable to Frontline Plus contains the same active ingredients and offers the same level of flea and tick protection at a better value. ZoGuard Plus for Cats is effective against all life stages of the flea, effectively breaking the life cycle and controlling re-infestations. Each package includes a monthly doses providing 12 weeks of protection. ZoGuard Plus for Cats is waterproof and will remain effective even after bathing, water immersion, or exposure to sunlight. Ingredients: fipronil.. 9.8%, S-Methropene.. 11.80%, Other ingredients 78.40%