Heartgard Plus Chewables are a vet-recommended monthly oral preventative designed to protect dogs from heartworm disease and treat and control roundworms and hookworms. They are a palatable, real-beef flavored chewable and are safe for puppies as young as 6 weeks old. Key Features: Active Ingredients: Ivermectin (prevents heartworm larvae development) and Pyrantel pamoate (treats and controls intestinal parasites). Protection: Effectively prevents heartworm disease and treats three species of hookworms and two species of roundworms. Administration: Given once monthly as a chew that most dogs readily accept as a treat. Dosing: Available in different strengths based on the dog's weight (Up to 25 lbs, 26-50 lbs, 51-100 lbs).