The Best Flea Treatments for Cats and Dogs

Fleas feed on the skin of a host to survive, and while they commonly live outdoors, they’ll happily hitch a ride indoors on a dog or a cat and then set up residence and multiply.

By Glenda Taylor | Updated Jan 13, 2021 1:07 PM

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Best Flea Treatment


The first signs your pet has fleas might come in the form of frequent scratching or biting at a part of its body, but in some cases, you might not discover the tiny black invaders until you notice them scurrying about in your home. Not only are flea bites painful to pets, the insects can transmit diseases such as typhus and cat scratch disease (Bartonella) to your pets, and they, in turn, can transmit those diseases to humans.

Eradicating fleas from your pets and your home once an infestation occurs can be lengthy and might require multiple treatments, so you may want to consider using a treatment on your pets that both kills fleas and prevents future infestations.

Once you’ve discovered your pet has fleas, the safest way to proceed is to contact your veterinarian to determine the best flea treatment. Your pet’s age, whether it’s pregnant or nursing a litter, or has a history of sensitivity to medications or topical insecticides will help determine the safest and best flea treatment for your furry friend.

Ahead, learn what to consider when choosing a flea treatment, and find out why the following products are good options for keeping your pets (and your home) flea-free.

  1. BEST OVERALL FOR DOGS: Bayer K9 Advantix II Flea, Tick and Mosquito
  2. BEST OVERALL FOR CATS: Capstar Fast-Acting Flea Treatment for Cats
  3. BEST BANG FOR THE BUCK: Advantage Flea and Tick Treatment Spray
  4. BEST SHAMPOO FOR DOGS: TropiClean Natural Flea & Tick Dog Shampoo
  5. BEST SHAMPOO FOR CATS: Vet’s Best Flea and Tick Waterless Bath for Cats
  6. BEST COLLAR FOR CATS: Bayer Seresto Flea and Tick Collar for Cat
  7. BEST NATURAL TREATMENT: Harris Food Grade Diatomaceous Earth for Pets
Best Flea Treatment


Types of Flea Treatment

Flea treatments are available in a handful of types, from prescription and over-the-counter medications to shampoos and collars that kill and repel fleas. Treatments are also available for ridding your home of fleas.

Oral Medications

Oral meds, known generically as “flea pills,” work by dispersing a systemic insecticide in your pet’s bloodstream after ingestion. When a flea bites your pet, the chemical enters the flea’s system and kills it. Some oral medications are only available by prescription from a veterinarian, but others are available over the counter.

Typically, over-the-counter meds are slightly less potent or designed to leave the pet’s bloodstream relatively quickly, meaning you might have to give your pet the medication every day for a few days until all the fleas are gone.

Prescription-only oral medications provide extended protection in your pet’s system against fleas and other insects, often including ticks. Both types of oral medications are chosen based on the animal’s body weight.

Topical Medications 

Topical medications feature liquid insecticides, such as permethrin and pyriproxyfen, that are applied directly to your pet’s skin, usually between its shoulder blades or on the back of its neck where it can’t lick off the medication. After application, the drug spreads throughout the animal’s skin, and when a flea bites, it ingests the chemical and dies.

Like oral meds, topical meds are available in both prescription and over-the-counter strengths, and veterinarians and pet owners must consider the animal’s age, weight, and whether it’s a dog or a cat when choosing. Some topical medications that are safe for dogs are harmful to cats.

Depending on the drug’s strength, it might protect for a few days, up to a month, or even longer, before you need to reapply it. These medications penetrate the skin’s surface so they won’t wash off, although the instructions might recommend waiting a day or two before bathing your pet or letting a pet swim.


Flea shampoos contain ingredients such as pyrethrum designed to kill existing fleas or make a pet’s coat so undesirable that the pests willingly leave. Many flea shampoo brands are available for both dogs and cats, but depending on their ingredients, they might not be suitable for kittens or puppies under a certain age, so read the label carefully. If a mother dog and her litter are both infected with fleas, a veterinarian can recommend a shampoo or other treatment that’s safe for all.


Flea powders are used mainly in the home rather than on a dog or a cat. They feature a variety of insecticides, both chemical and natural. Typically, you sprinkle the powder on carpets and upholstery, brush it in, and allow it to remain there for a few hours or longer before vacuuming.

A flea infestation in a house can develop rapidly because female fleas can lay dozens of eggs daily, and those eggs hatch in 10 to 12 days. Treating carpet and upholstery with flea powder should be done at least twice, with the second treatment being 12 days after the first to kill any fleas that hatch after the first treatment.


Flea sprays are designed for use on pets, as well as in the home. They contain insecticides that kill adult fleas on contact, and some may leave a residue behind that kills any fleas that subsequently hatch. Only use a flea spray in the manner it was intended—don’t use a spray for carpeting and upholstery on your pup and don’t use a spray for animals on the carpet.


Flea collars contain insecticides that kill and repel fleas and other insects and are usually safe when used as directed. If your pet tends to slip out of its collar, however, or you have more than one pet, and there’s a chance one will chew on the other’s collar, this might not be the best treatment option. Chewing on a flea collar can lead to poisoning, especially if the pet ingests a portion of the collar.

What to Consider When Choosing the Best Flea Treatment

When choosing a flea treatment, don’t just grab the first product you see on the shelf; consider their differences. Treating fleas is not a one-and-done process—in addition to treating the pet, you’ll also need to treat its bedding and perhaps even your home.

Dog vs. Cat Flea Treatments

Certain chemical insecticides, such as permethrin, safely treat fleas on dogs but can make cats sick. Use only a product labeled as safe for your pet—don’t use a product intended for dogs on a cat.

Natural vs. Chemical Treatments

Manufacturers use both chemical and natural ingredients in their flea treatments. For example, while permethrin is safe for dogs but toxic for cats, a natural alternative, pyrethrin, which is derived from the chrysanthemum plant, is a safe alternative for cats.

Protection Period 

Some flea treatment products, such as shampoos, are designed to kill fleas immediately and repel them for a few days, while oral and topical medications can last up to 1 month, or even longer, depending on the ingredients. Flea collars might repel fleas and other insects for up to 8 months.

Additional Protection

Depending on the flea treatment you choose, it might offer protection against additional pests, such as ticks, mosquitos, botflies, and other bugs. These insects also can carry diseases and parasites that can harm your pet’s health.

For example, a mosquito bite can transmit heartworms, a potentially fatal condition for dogs, so you might want to consider using a treatment that kills other pests as well as fleas. Your veterinarian can tell you what types of insects pose the most significant health risk in your area.

Our Top Picks

The following products will get rid of fleas—and other pests—on your pet and in your home, and are considered safe when used as directed. If you’re trying a new treatment for the first time, though, keep a close eye on your pet. If your pet develops any unusual symptoms, including skin irritation, sneezing, watery eyes, or changes in behavior, discontinue use and consult your veterinarian.

Best Overall For Dogs

Best Flea Treatment K9

Bayer K9 Advantix II Flea, Tick, and Mosquito Prevention is a long-lasting topical flea mediation, capable of killing fleas, lice, ticks, and mosquitoes, while repeling biting flies. The product starts killing fleas within 12 hours of application and continues killing them for up to 30 days.

It comes in easy-to-use, single-dose packets and should be applied directly to your dog’s skin in a spot where the dog can’t lick. Advantix II is intended to treat dogs weighing more than 55 pounds, and it should not be used to treat cats or puppies less than 7 weeks old.

Best Overall for Cats

Best Flea Treatment Caostar

Consider Capstar Fast-Acting Flea Treatment for Cats as a safe treatment for fleas on felines. The product is designed to start killing fleas within 30 minutes of being eaten. This flea-only medication (not intended to kill ticks) can be administered up to once per day—or whenever you notice fleas on your cat.

It’s made to treat cats between 2 and 25 pounds, but it is not safe for kittens less than 4 weeks old. Most cats like the taste and will eat the pill by itself, but if your cat balks, try tucking the tablet in a bit of soft cat food or tuna fish.

Best Bang For The Buck

Best Flea Treatment Advantage

You don’t have to spend a lot of money to give your pet some relief from fleas with Advantage Flea and Tick Treatment Spray. The spray is designed to kill adult fleas and their eggs on contact and will also kill ticks. It’s meant to be sprayed on your pet’s head and body (cover the dog’s eyes and avoid getting the spray near the mouth, nose, and genitals). Once the fur is saturated, allow the product to dry naturally.

This spray is intended for dogs and puppies over 6 months old, but should not be used on cats. There’s also an Advantage Spray for Cats, which is safe for felines older than 7 months.

Best Shampoo For Dogs

Best Flea Treatment TropiClean

With a handful of natural insecticides and repellents, including lemongrass oil, cedarwood oil, and clove oil, Tropiclean Flea & Tick Shampoo for Dogs kills both fleas and ticks on contact and will continue to repel the little buggers for up to 7 days. It’s designed for use on dogs older than 12 weeks.

For the best results, thoroughly wet the dog’s coat with water and then apply as much TropiClean shampoo as needed to work up a rich lather. Do not get the shampoo into the dog’s eyes. The shampoo should be allowed to remain in the coat for 5 to 7 minutes before rinsing it away thoroughly. This shampoo should not be used to bathe pregnant or nursing dogs.

Best Shampoo For Cats

Best Flea Treatment Waterless

If you’ve ever bathed a cat, you know it’s not the easiest thing to do, but Vet’s Best Flea Waterless Foam Treatment for Cats can help. Using the waterless treatment can prevent unearthly howls and painful scratches on your body. It is a simpler (and safer) way to bathe your fur baby. The product dispenses as a foam that you can massage softly into the cat’s fur, and there’s no need to rinse it out.

The dry shampoo contains gentle essential oils, including peppermint and eugenol, and it kills fleas, flea eggs, and ticks on contact. The scent is soothing, but the product should not be used on kittens younger than 12 weeks.

Best Collar For Cats

Best Flea Treatment Bayer

The Bayer Seresto Flea and Tick Collar for Cats will protect your feline for up to 8 months, and it features three visibility reflectors that shine in the dark to alert you (and motorists) to the presence of your cat.

The time-released insecticide starts killing fleas within 2 hours, and after 48 hours, it will prevent tick infestations. Nongreasy and odorless, the Seresto collar for cats is designed to be used only on adult cats and kittens over 10 weeks old.

Best Natural Treatment

Best Flea Treatment Harris

For a safe and natural treatment of your pet’s flea problem, look to Harris Food-Grade Diatomaceous Earth (DE), which is made from finely ground fossils of diatoms, a type of algae that grows in fresh water. This nontoxic white powder can be sprinkled on carpeting, pet bedding, and even rubbed into your pet’s coat to kill fleas.

When fleas and other insects come into contact with DE, the powder—which feels smooth to the human touch—cuts the insects’ soft underbellies, causing them to dehydrate and die. Food-grade DE is safe enough that it often is mixed into pet and livestock food to control internal parasites. Sprinkle the powder around doorways and foundations to kill unwanted insects, too.

FAQs About Flea Treatments

No one likes the idea of a pet suffering from flea and tick bites, but if this is the first time you’ve treated your pet, it’s only natural you have questions. Here are some commonly asked questions and the answers.

Q. How do I check for fleas?

If your pet has fleas, the first sign is often the pet scratching itself with a hind leg or chewing intensely on another part of its body. To verify if the problem is fleas, brush your pet’s fur aside and look for tiny, black, fast-moving bugs on its skin. Fleas also can jump off your pet and breed in your home’s carpeting and upholstery, so be on the lookout for tiny black bugs there as well.

Q. What is dog flea medicine, and how does it work?

Flea medicine contains insecticides designed to be applied to your pet’s coat or taken orally. The most potent medications are only available by prescription, but many over-the-counter flea meds will also offer relief.

Q. Should I choose an oral or topical treatment?

It’s really up to you and your pet. If your pet takes medications without a fuss, oral treatments are quick and convenient. If your pet stubbornly refuses to take medications, even when they’re disguised in food, a topical medication may be easier for both of you.

Q. What ingredients kill fleas?

A wide variety of chemical and natural insecticides can kill fleas; some of the most common chemical ones include fipronil, s-methoprene, imidacloprid, and permethrin. Natural ingredients, such as clove oil, cinnamon oil, and diatomaceous earth, also are popular for killing fleas.

Q. How long does it take to break the flea cycle?

Under optimal circumstances, it takes about 12 days to break a flea cycle. It takes approximately 2 weeks for a flea egg to hatch and then mature to the adult stage when female fleas can lay eggs. Along with treating your pet, if fleas are in your home, you’ll need to treat your pet’s bedding, carpeting, and upholstery two times. The second treatment should be 12 to 14 days after the first, which will kill any fleas that hatched after the first treatment.