Frontline Extra Large Dog is a spot on liquid (10% Fiprinol) for treatment & prevention of fleas & ticks in dogs. Frontline Extra Large Dog can also used in the treatment of flea allergy dermatitis. May be used from 8 weeks of ageBuy 2 packs of 6 and SAVE! Active ingredient in Frontline Extra Large Dog is fiprinol Voted Testers Choice 2011 by Your Dog Magazine for ease of use and cost