Advantage for dogs contains Imidacloprid. This active ingredient is a powerful insecticide. It starts killing fleas within an hour of application. It eliminates adult fleas and larvae in your dog's surroundings and thus prevents further re-infestation. This monthly treatment kills adult fleas within 12 hours of application and kills about 99% flea larvae found on dog and in its surroundings. It prevents several diseases caused due to fleabites and protects dogs from its harmful diseases. It reduces outbreaks of Flea Allergy Dermatitis and controls lice. Advantage is a monthly, spot-on treatment that protects your dog from fleas. Kills adult fleas and protects against re-infestation for a month Kills flea larvae and eggs Provides fast relief, stops fleas biting within 3 to 5 minutes of application As well as killing adult fleas, Advantage kills flea eggs and larvae to break the flea life cycle and protect your dog from re-infestation for a whole month. It provides fast relief, stopping fleas from biting within 3 to 5 minutes of application and kills the adult fleas and larvae within 20 minutes. Advantage is safe for puppies of any age, as well as pregnant and lactating females.