Advantage Once-a-Month Topical Flea Treatment for dogs and puppies. Kills 98-100% of the fleas on dogs within 12 hours. One treatment prevents further flea infestation for up to four weeks. Kills fleas before they lay eggs. The successive feeding activity of fleas on pets may elicit a hypersensitivity skin disorder known as flea allergy dermatitis (FAD). Treatment of pets with Advantage rapidly kills fleas and may reduce the incidence of this condition. Reinfesting fleas are killed within two hours with protection against further flea infestation lasting for up to four weeks. Pre-existing pupae in the environment may continue to emerge for six weeks or longer depending upon the climatic conditions. Larval flea stages in the pets surroundings are killed following contact with an Advantage treated pet. Advantage remains efficacious following a shampoo treatment, swimming, or after exposure to rain or sunlight. If re-treatment becomes necessary earlier than four weeks, do not re-treat more than once weekly.