Elanco Advantage II Topical Flea Treatment & Prevention for Dogs 6-Month Supply XL Dogs (over 55lbs)Advantage II is the vet recommended prevention and treatment of flea and lice infestations in dogs. Kills adult fleas, flea larvae and flea eggs to deliver total flea protection to your dog or puppy. In fact, within 12 hours of application, Advantage II gets straight to work killing fleas through contact, so they dont have to bite your dog to die. This 30 day treatment effectively breaks the flea life cycle, controlling existing flea and lice