Heartworm disease can be a serious threat to dogs; it can lead to lung disease, heart failure, and damage to other organs in the body. It can involve hospitalization with painful injections, which can be traumatic. Prevention is still the best treatment. Heartworm disease is transmitted to your cat or dog by infected mosquitoes, who got infected by feeding on an infected animal. Signs of heartworm disease are lack of appetite, weight loss, coughing, reluctance to exercise, and fatigue. Heartgard is a chewable tablet that helps prevent heartworm disease for cats and dogs, kills heartworm larvae and treats and controls roundworms and hookworms. Dogs and cats get internal parasites by eating feces, infected animals, or contaminated toys. Sometimes worms can come directly from their mothers. If worms are left untreated, they can become dangerous and cause blood loss, coughing, diarrhea, weight loss, and inflammation. Heartgard has a powerful formula that kills these parasites before they can spread diseases and cause damages. Heartgard is available as tasty chewable tablets for cats (Heartgard Chewables) and dogs (Heartgard Plus Chewables).