A woman holds a small puppy in her arms
A woman holds a small puppy in her arms

When to Start Your Puppy on Heartworm Disease Prevention

When caring for your brand-new puppy, heartworm disease prevention should be a top priority. The American Heartworm Society (AHS) recommends that you start your puppy on heartworm disease prevention at no later than 8 weeks of age.1 Heartworm disease prevention for puppies is critical, as puppies can become infected with heartworms via a bite from an infected mosquito on the first day of their life. HEARTGARD Plus chews are approved as safe for puppies as young as 6 weeks.


Once your puppy is on a heartworm disease preventive, continue to give your dog a delicious real-beef HEARTGARD Plus chew each month, all year long, to ensure full protection from the risk of heartworm disease.

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A golden retriever puppy sits in the backyard

Can Puppies Get Heartworms?

Yes. Heartworms are transmitted by mosquitoes—if an infected mosquito bites your puppy, your puppy is at risk of developing heartworm disease. Once infected, the heartworm larvae will develop into adult heartworms over the next 6 to 7 months.2 These heartworms can cause permanent scarring of the vessels and the lungs even prior to the dog testing positive.

A woman pets her golden retriever puppy

Can Puppies Get Heartworms Even in Cold Climates?

Heartworm disease happens in all climates, in all 50 states, and at any time during the year.3 The infection is caused by parasites that are transmitted by mosquitoes.2,3 Heartworms don’t discriminate based on age—your young pup is just as likely as an older dog to contract heartworm disease. Because of this, a heartworm disease preventive is one of the most important monthly medications for all dogs, just like flea and tick protection.


HEARTGARD Plus chews are the #1 vet-recommended real-beef chew that prevents heartworm disease in puppies and adult dogs.4


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A woman is about to feed her puppy a Heartgard treat | HEARTGARD® Heartworm Protection

The Importance of Heartworm Disease Prevention for Puppies

Heartworm disease can be deadly, but heartworm disease prevention for puppies is easy with HEARTGARD Plus Chews. Beginning heartworm prevention early is critical if you want to give your dog a long and healthy life.


Starting heartworm disease prevention early shouldn’t be your only focus—it’s equally important to administer the preventive every month, and all year long.

Need a prescription? Find a vet near you using our Find A Vet tool.