Mosquitoes, ticks, and fleas can ruin a good trail day, but reaching for your own bug spray could land your dog in the ER. Here’s how to safely shield your four-legged hiking buddy.
Just like humans, dogs need bug spray too, but the wrong ingredients be deadly (Photo: Ирина Мещерякова/Getty Images)
Published June 19, 2026 05:09AM
Summer is prime for dog-friendly outdoor adventures, from hiking scenic trails to spending evenings along the river. But warmer weather also brings with it a less adorable companion: mosquitoes. Just like humans need bug spray before heading out into skeeter country, our furry friends can also benefit from using insect repellent.
Itchy bites aside, these pesky insects also pose a threat to dogs by transmitting heartworm disease—a potentially serious, even deadly, condition.
“Mosquitoes are known for being a nuisance in the U.S., but they can also transmit deadly heartworm disease to our dogs,” Stephanie Montgomery, veterinarian and CEO of the AKC Canine Health Foundation, told Outside. “Fortunately, there are a few simple precautions that can help keep your dog safe.”
Before you head out on your next summertime adventure with your furry friend, be sure to keep them safe by following these simple rules.
Use Appropriate Heartworm Prevention
Heartworm disease is a serious, potentially fatal condition in dogs transmitted through mosquito bites. After a dog ingests heartworm larvae, the parasite can grow up to a foot long and live in the heart, lungs, and surrounding blood vessels, according to the American Heartworm Society.
While heartworm prevention products do not repel mosquitoes, Montgomery says these medications kill heartworm larvae transmitted by mosquitoes before they can cause disease.
“Consult your veterinarian about the best option for you and your dog,” she said.
Human Insect Repellents Can Be Dangerous for Dogs
“Never apply human insect repellent products like DEET on your dogs; these products can be toxic if ingested, and it’s no secret that most dogs like to lick their fur and paws,” Montgomery said.
There are a handful of dog-friendly bug sprays available, including Wondercide Flea, Tick, and Mosquito Spray and Nantucket Spider Bug Repellent for Dogs. Both products use natural essential oils and are formulated without ingredients that can irritate dogs. Always ask your veterinarian about approved mosquito-repelling products.
Mosquitoes hate citrus, and the Animal Humane Society recommends rubbing citrus from tart fruits like lemons on your dog’s coat. You can also plant mosquito-repelling herbs like basil, catnip, lemon balm, and rosemary in your yard to ward off insects.
When In Doubt, Dump It Out
Whether in buckets, pools, or ponds, stagnant water is a breeding ground for mosquitoes.
“You can help yourself and your dog at home by checking for stagnant water, where mosquitoes breed,” Montgomery said. “Check and empty places like bird baths, flowerpots, clogged gutters, outdoor furniture covers, and other areas where water can collect.”
Bites Happen—Don’t Freak Out
If your dog gets bitten, Montgomery says not to panic.
“Most mosquito bites cause only mild irritation. Just try to discourage scratching, chewing, or licking, which can worsen irritation and lead to infection,” she said. “If you notice significant swelling, persistent itching, hives, facial swelling, or any other concerning reaction, contact your veterinarian for guidance.”
Avoid using human hydrocortisone creams or sprays unless specifically directed by your veterinarian.
