Frontline Spot on X Large Dog is for the prevention of infestations by Fleas and Ticks in dogs, and is part of a treatment strategy for Flea Allergy Dermatitis in dogs where this has been previously diagnosed by a Veterinary Surgeon. Frontline Spot On X Large Dog controls infestations with biting lice on dogs. It is effective against fleas for approx 2 months and ticks for up to 1month in dogs. It also controls lice within 48 hours. Routine treatment is advised to prevent flea infestations.FRONTLINE Spot On Dog can be used in puppies from 8 weeks of age and weighing over 2kg.