Advantage II Once-A-Month Cat & Kitten Topical Flea Treatment effectively kills fleas, flea eggs and flea larvae. Specially formulated to provide cats and kittens with fast-acting, superior flea protection, Advantage II flea control drops kill fleas within 12 hours of application. This special topical feline flea formula helps to control existing flea infestations on your cat, while it also works toward preventing further infestations. This topical Advantage II Flea formula even remains effective following a shampoo treatment, swimming, or after exposure to rain or sunlight. Regular use of flea medicine for cats not only gives your favorite felines and precious kittens the flea protection that they need and deserve, but it also gives you peace of mind that their chances of developing an infestation are decreased significantly. This easy-to-use flea treatment only needs to be applied once a month to your cats and kittens. In addition, this flea prevention formula is safe for use with cats and kittens 8 weeks of age and older. Advantage II does not expire if it remains unopened and is stored properly according to the package instructions.