Heartgard Plus contains an intestinal wormer as well as one to kill heartworms, so nothing else is needed. The generic, Heartgold Plus, is much cheaper and excellent. I buy it from www.pets-megastore.com.au It always arrives quickly, and there is no need for a prescription; you'll find that a lot of vets are unwilling to sign prescriptions for companies that offer lower prices if they sell the product in their own office.