Frontline Spray provides long-lasting, effective control of fleas and ticks on your cat and dog. Kills up to 100% of existing fleas in less than 24 hours. Frontline Spray continues killing fleas for an entire month or more. Recommended for: Severe existing flea and tick infestations, Multi-pet households, Initial treatment of flea allergy dermatitis (FAD.) Dogs and cats as well as puppies and kittens 8 weeks of age or older.