How to Treat Fleas and Prevent Their Return

Though there are an estimated 2,500-plus species of fleas worldwide, the most common one found in North America is the cat flea. These tiny, wingless insects can live on both cats and dogs. 

Fleas thrive in warm weather. Because climates vary across the nation, one state’s “flea season” might not be the same as another’s. Here’s a handy map to help break it down. Though they prefer it balmy, when they’re outside in your yard, fleas like to find a cool, shady spot—think beneath trees and bushes, or amid that tall grass you keep meaning to trim.

Once you’re positive you have a flea problem, bathe all the cats and dogs in the home (even those that aren’t scratching) with a mild soap (Hansen suggests Dawn dish detergent because it can cut the surface tension of water, making it easier for the fleas to drown), then comb out any fleas with a metal flea comb. The American Veterinary Medical Association (AVMA) advises you to consult a vet “if your pet excessively scratches, chews or licks their coat, or persistently shakes their head or scratches their ears.” 

Some pet owners may want to go natural and apply essential oils topically in order to rid their animals of fleas. Los Angeles-based veterinarian LaDissa Moore of IVS Mobile Vets and Grooming Spa urges caution: “Essential oils can be very irritating to pets,” she says, adding that a vet consultation should always come first.

Certain cat breeds can be particularly sensitive to botanicals. According to a study in the journal Insects on controlling cat fleas, plant-derived flea products, such as tea tree oil and peppermint oil, have been reported to have adverse effects on both cats and dogs, including depression, weakness, or seizures.

If you’re going to take the over-the-counter route, veterinarian Cecily Jennings of Haven Veterinary Clinic in Houston says to make sure the product you use is suitable for your pet’s weight range and age, and follow the label instructions carefully. “I would not recommend anything without an EPA [Environmental Protection Agency] or FDA [Food and Drug Administration] approval,” Jennings says. “These agencies require stringent testing prior to products being approved for use.”

According to Moore, it’s important to keep your pet’s flea cleansing regimen simple. “Don’t douse your animal in flea powders or topical flea sprays, because a lot of times they’ll lick themselves and get really sick,” Moore says, noting that, too often, pet owners will drench pets in powder, then put powder on the flea collar and add flea spray on top of it all. A better option is to choose one of those methods, Moore says.

To remove fleas from your home, give rugs, carpets, and upholstered furniture a thorough once-over using a high-efficiency particulate air or HEPA-equivalent vacuum cleaner every day. Rooms with hardwood or linoleum floors will be easiest to clean. If, however, you have rugs and carpets that are particularly thick, Hansen recommends using a steam cleaner. 

Flea sprays marketed for the home don’t get to the heart of the problem because they rarely reach the eggs, larvae, and cocoons where they’re nestled. “For the pesticide to kill them, it has to get to them,” Hansen says. “And if you have a thick carpet, they’re at the bottom, woven in. Unless you want to drench the whole thing so it gets wet all the way down to the bottom where they are, it’s not going to do anything.”

“Prevention, prevention, prevention is the rule of thumb for keeping fleas and ticks at bay,” Jennings says, adding that “newly acquired pets should be started on age-appropriate flea and tick medication as soon as possible.”

Jennings suggests choosing the treatment method that’s easiest to give to your pet. “If they are picky about what they eat or fight taking a pill, use a topical product,” she says. “If they eat anything that is dangled in front of them, consider a chewable as a treat once a month.” It’s also important for pet owners to remember to consistently give their pets an anti-flea product.

Moore recommends prescription oral medications such as Simparica Trio (sarolaner, moxidectin, and pyrantel) and Bravecto (fluralaner), both of which are chewables. For prescription topical treatments, she recommends Revolution (selamectin) for dogs and Revolution Plus (selamectin and sarolaner) for cats.

“If the animal has seizures, we don’t recommend oral flea preventive; we recommend topical flea preventives because that could potentially decrease the seizure threshold,” Moore says, adding that oral medications are ideal for animals that experience local contact allergies and hair loss resulting from topical medications.

Whichever type of preventive you choose, make sure it’s species-specific.

“Definitely don’t use dogs’ flea preventatives for cats,” Moore says. (Cats are much more sensitive to the chemicals used in flea meds.) “People will just do a half-dose of the dog [medicine] for the cat. That actually causes real toxicities.”

(According to the AVMA, some preventives shouldn’t be used on puppies and kittens, pregnant pets, and some older pets. Discuss all medication options with your vet prior to giving your dog or cat a medication.)

As for flea collars—well, Hansen advises against them. He points out that one popular product—the Seresto flea and tick collar for cats and dogs—has been linked to what the Center for Biological Diversity estimates is more than 2,700 pet deaths. 

“The active ingredients (AIs) for the collar are imidacloprid (which belongs to a class of chemicals called neonicotinoids) and flumethrin,” Hansen says. “There is some question whether the two AIs might have synergistic effects that could enhance toxicity.”

According to the Center for Biological Diversity: “Flumethrin is a pyrethroid that has been shown to have troubling health impacts on dogs, cats, and humans. When combined, imidacloprid and flumethrin are believed to have synergistic effects that make them even more toxic to fleas and ticks and, potentially, to pets and people.”

The EPA has allowed the Seresto flea and tick collars to remain on the market, but the manufacturer, Elanco, now includes label warnings on their products.

“In general, I think flea and tick collars are not a good idea due to potential exposure to not only the pets but also humans who play with or cuddle them,” Hansen says.

A prescription treatment for fleas sounds like an easy enough fix, but there’s more to flea-proofing than just administering chewables and drops. Hansen advocates for implementing Integrated Pest Management, a science-based strategy that the EPA reports is both effective and environmentally sensitive.

The IPM method involves three main steps: checking your pet’s coat often, monitoring for fleas regularly, and vacuuming fleas rather than spraying them.

You should spot-check your dog or cat’s coat on a regular basis using a metal flea comb, especially after you’ve returned home from outings where fleas might spread—like the dog park or the homes of friends with pets of their own.

An IPM protocol guide suggests keeping a container filled with water and a few drops of dish soap handy while you comb. Any fleas you comb out can then be plunged into that water, where they’ll drown. 

To prevent infestation, you should also vacuum frequently and wash animal bedding in hot water every two to three weeks. Flea traps from the pet store work fine as a measure of monitoring your space. 

“The one simple solution is to just wear white socks and walk through some of the areas [of your home],” Hansen says. “If the fleas are out, you’ll be able to see them because they’ll be hopping on the socks.”

For a nontoxic way to flea-proof the home, Moore recommends diatomaceous earth, which causes the fleas to dry out and die. Diatomaceous earth can be sprinkled in the corners of rooms and near furniture where pets often sleep, then vacuumed thoroughly.

There are a few key ways to make your outdoor spaces inhospitable to fleas. The Centers for Disease Control and Prevention says you should avoid overwatering your landscape because that can create the humid conditions in which fleas thrive. You should also mow grass, clear weeds, and rake leaves often to remove shady flea havens. Opossums, raccoons, and stray cats can bring fleas to your outdoor areas. Keeping tight lids on compost and trash cans, removing bushy hiding spaces, and sealing holes can help keep those creatures out of your spaces, as can removing outdoor pet food bowls.

Try to stay patient. According to the CDC, moderate to severe infestations can take months to control. Their advice: “In order to get rid of fleas in all stages of the life cycle, two or more follow-up treatments within five to 10 days after the first application are needed.”

From giving pets a regular once-over and keeping an eye out for fleas and their droppings to tidying up your yard, the important takeaway is that vigilance is crucial for getting fleas out for good.