Heartworms (up to 30cm long in dogs) live in the heart and blood vessels of the lungs, interfering with circulation and damaging tissues. This may eventually cause heart failure. Left untreated, this can result in the death of your dog. All untreated dogs are at risk of being infected by potentially deadly heartworm. That's why it's so important to protect your dog. Luckily, it's easy with HEARTGARD30® PLUS. It comes in a great-tasting real beef treat that dogs love. What’s more it also provides protection against roundworm and hookworm. Don't take chances – make sure your dog's got the protection it needs.