Is Citronella Safe for Dogs? A Veterinarian Provides Guidance

The 6 Best Flea Treatments For Dogs In 2024

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The best flea treatments for dogs prevent and kill pesky parasites safely and effectively. Many dog flea medicines also treat ticks and lice and prevent heartworm infections. These medications come in the form of topicals, chewable tablets, shampoos, and collars. 

To choose the top flea and tick medicines, we asked veterinarians how to prevent and eliminate fleas and ticks in puppies and adult dogs. We also researched products using the Companion Animal Parasite Council's quick product reference guide. Our top pick is Advantage Multi, a prescription medicine that prevents and controls fleas and protects against heartworms. To treat both fleas and ticks, we recommend Frontline Plus for dogs, an over-the-counter (OTC) topical medicine.

It's important to ask your veterinarian what type of flea and tick preventive is best for your dog. The ideal treatment depends on your dog's temperament, lifestyle, and the most common parasites where you live. 

Learn more about how Business Insider Reviews tests and researches pet products.

Our top picks for the best flea treatments for dogs

Best topical preventative overall: Advantage Multi for Dogs - See at Chewy

Best OTC topical preventative: Frontline Plus for Dogs - See at Chewy

Best pill: Simparica TRIO - See at Chewy

Best for young puppies: Capstar for Dogs - See at Chewy

Best collar: Seresto Flea and Tick Collar for Dogs - See at Chewy

Best shampoo: Adams Plus Flea and Tick Shampoo with Precor - See at Chewy

Best topical preventative overall Advantage Multi for Dogs

With just one easy monthly application, Advantage Multi for Dogs treats, controls, and prevents more parasites than any other topical product.

Not even the best flea and tick medicine for dogs controls every harmful parasite, but Advantage Multi for Dogs comes close. It's also one of our top picks for the best flea and tick treatments for puppies.

Advantage Multi is a topical spot-on product that contains the active ingredients imidacloprid and moxidectin, which prevent flea infestations by killing adult fleas before they can lay eggs. It also prevents heartworm, mange mites, and three intestinal parasites: roundworms, hookworms, and whipworms. If your dog already has worms, your vet may recommend treating them with one of the best dog dewormers. As with all medications that prevent heartworm, your dog needs a heartworm test before starting Advantage Multi and annually after that.

Advantage Multi is easy to use: Every 30 days, apply it to the dog's skin at the base of the neck between the shoulder blades. The liquid medication is absorbed and dries within hours. Unlike other topical preventatives, you don't need to wear gloves to apply Advantage Multi. If you get the product on your hands, simply wash them with soap and water. For a half-hour after application, keep dogs from licking the application site, either on themselves or other treated dogs. Children should not touch the application site for two hours after application.

Advantage Multi does not prevent ticks. If ticks are a concern, consider Frontline Plus for Dogs, Bravecto Topical for Dogs, or K9 Advantix II.

Best OTC topical preventative Frontline Plus for Dogs

Available without a prescription, Frontline Plus for Dogs kills adult fleas, flea eggs, flea larvae, ticks, and chewing lice on contact.

Among the best flea treatments for dogs, Frontline Plus is our top nonprescription recommendation because it kills ticks and fleas, controls flea infestations, and kills chewing lice, all with one easy application. When used primarily for flea control, each dose of Frontline Plus lasts up to three months. If ticks or biting lice are a concern, apply it monthly.

Frontline Plus has been used and trusted by pet owners for over two decades. Parasites die on contact — they do not have to bite your dog for the treatment to work. Its active ingredients, fipronil and S-methoprene, work together to kill parasites and break the flea life cycle. Fipronil kills adult fleas and ticks, while S-methoprene prevents flea eggs, larvae, and pupae from developing. If your dog has a lot of fleas, it can take up to a month of consistent use to get rid of them because flea eggs can be in your home but not on your dog.

Frontline Plus is easy to use. Squeeze all the liquid in the tube onto one spot of your dog's skin between the shoulder blades. The liquid medication spreads across your dog's skin and gets stored in the oil glands. It distributes itself continuously via the hair follicles.

Best pill Simparica TRIO for Dogs

Simparica TRIO treats, controls, and prevents more parasites than any other oral product, offering a full month of protection with one easy-to-give flavored pill.

Our pick for the best flea treatment for dogs in pill form is Simparica TRIO. This chewable tablet is fast-acting and kills more parasites than any other oral product. It starts to work within four hours and kills 100% of adult fleas on dogs within eight hours.

Choosing between an oral or topical flea control product is tough for some dog owners. There are pros and cons to each type of product. In some cases, an oral preventive is a better choice. For instance, some dogs with sensitive skin can't tolerate spot-on treatments. "Oral products have the benefit of broad coverage to reach every spot of skin without the chance of the product being washed off," says Dr. Kate Crumley, a veterinarian with Blue Heron Consulting.  

You can give the liver-flavored tablets with or without food once a month. The treatment contains three ingredients — sarolaner, moxidectin, and pyrantel — and provides an entire month of protection against more parasites than any other oral product. Simparica TRIO is also safe for some of the youngest puppies and smallest dogs. It requires a prescription from your veterinarian, as well as a negative heartworm test. It should be used with caution in dogs with a history of neurologic disorders such as seizures.

Best for young puppies Elanco Capstar for Dogs

Capstar for Dogs is safe for puppies as young as 4 weeks old and starts killing fleas within 30 minutes.

Fleas should be eliminated as quickly as possible for heavily infested dogs, especially young puppies. Available without a prescription, Capstar for Dogs is the only flea control product safe for puppies as young as 4 weeks and weighing at least 2 pounds. With other topical and oral flea control products, puppies must be at least 8 weeks old and sometimes older. 

The active ingredient in Capstar, nitenpyram, works within 30 minutes and kills more than 90% of adult fleas on dogs in as little as four hours. Its protection against fleas lasts only 24 hours, but it is safe to give daily if necessary. Daily dosing is helpful for young puppies that might not be old enough to use an oral or spot-on product that offers long-term protection. Owners should follow up with a flea control product that provides a month or more of protection once the puppy is old enough.

Best collar Seresto Flea and Tick Collar

The Seresto Flea and Tick Collar for Dogs offers eight months of protection against fleas and ticks in all life stages.

A March 2021 investigation by USA Today reported 1,700 animal deaths and other adverse reactions linked to Seresto flea collars. It's unknown if the EPA-approved pesticides used in the collar caused these incidents. You can read more about the safety of Seresto collars in our FAQs.

Flea collars were once the main option for flea control, but most don't offer the same level of protection as topical and oral medicines. One noteworthy collar is the Seresto Flea and Tick Collar for Dogs, which uses sustained-release technology to provide eight months of continuous protection against adult fleas, flea larvae, four species of ticks, chewing lice, and mange mites.

In general, topical spot-on and oral preventatives are the most effective flea control for dogs, but the Seresto collar might be a good option in certain situations. Dr. Kelley Lay, a relief veterinarian in Nashville, Tennessee, says that traditional flea and tick collars are generally not very effective. She has even seen allergic reactions and other issues with some of them. However, she has found the Seresto collar safe and effective and recommends it to clients with pets who don't tolerate topical or oral flea and tick preventives.

The collar is nongreasy, odor-free, lightweight, and adjustable for dogs of all sizes. It can be worn alongside your dog's regular collar and has a two-step safety system to keep your dog safe if the collar gets caught on something. The collar's active ingredients, imidacloprid and flumethrin, are released in low concentrations over your dog's skin and coat to kill fleas and ticks on contact — parasites do not need to bite your dog for the collar to work. It kills 100% of fleas within 24 hours of placing the collar on your dog. You don't need to remove this water-resistant collar during swimming or bathing with one of the best dog shampoos.

Best shampoo

Our top pick for the best flea shampoos for dogs is Adams Plus Flea and Tick Shampoo. In addition to killing fleas, flea eggs and larvae, ticks, and lice for up to 28 days, this shampoo soothes skin that has become dry and irritated from flea bites and constant scratching. 

The shampoo contains pyrethrins and S-methoprene (Precor) synthetic pesticides commonly included in flea and tick shampoos. It also contains piperonyl butoxide to enhance the pesticides' effectiveness. Oatmeal helps heal irritated and itchy skin, and the shampoo has a pleasant coconut scent. 

Lay says that flea shampoos are fine to use alongside prescription flea control medications but shouldn't be considered the first or best line of defense against fleas. Veterinarian-prescribed, year-round flea prevention remains the gold standard. Despite marketing claims, these shampoos do not provide substantial flea protection after the bath and may leave dogs susceptible to repeated infestations. Some ingredients in shampoos can also irritate the skin.

What to look for in flea and tick medicine for dogs

Safety and efficacy: FDA- or EPA-approved products have undergone rigorous safety and efficacy testing before going to market.

Number of parasites treated: Using a product that protects against more than just fleas is convenient. While your veterinarian can advise you on which product is best for your dog, we generally favor products that cover more parasites. 

There are some exceptions. For instance, Capstar treats only fleas, but it is the only medicine available for puppies younger than 6 weeks. OTC products, like Frontline Plus, protect against additional parasites such as ticks and lice but not heartworms. Products that treat heartworm always require a veterinary prescription.

Ease of use: The easier it is to use a product, the better. For example, chewable tablets are quick and easy to give your dog, provided they like the flavor. Products that require a person to wear gloves when they apply it or require the treated animal to stay away from children or other pets for a while may be a hassle. 

Minimum age and weight: Flea treatments are intended for dogs above a minimum age and weight. Your options for a very young puppy will be more limited until they are older and weigh more. 

Prescription vs. Over-the-counter: Some flea control products are available over the counter. Others require a prescription from your veterinarian. You can buy prescription medicines from your veterinarian or online pet pharmacies and stores like Chewy, Petco, and PetSmart.

Prescription flea control products typically cost more than OTC options because they protect against more parasites, most importantly, deadly heartworms. Dogs must test negative for heartworms before starting a heartworm preventive. 

Types of flea and tick medications: There are several types of treatments, including topical, oral, collars, shampoos, and sprays. Cost, convenience, ease of use, and effectiveness vary among these products. Your vet can help you determine the best type for your dog. We advise against flea sprays because topical spot-ons and oral products are more effective. Remember that some dogs with sensitive skin may not tolerate topical products. Crumley says that frequent bathing or swimming may also reduce the effectiveness of a topical product that remains on the skin's surface.

Natural vs. Synthetic: Our experts do not recommend using natural products instead of veterinarian-recommended topical and oral flea control. While natural treatments can deter fleas and ticks, they won't eliminate an infestation. "If you use them, be prepared to apply them at least daily before your pet goes outside for the best chance of keeping the hitchhikers from latching on," says Crumley. If you also have kitties at home, avoid natural flea control products containing essential oils because some can be toxic to cats.

Other pets in your home: Any product labeled for use in only dogs should never be given to a cat. Some ingredients can be toxic to cats. While any dog-only flea product can harm felines, cats are especially sensitive to pyrethrins. If you're looking for a safe product for your cat, check out our guide to the best flea treatments for cats.

How we selected the best flea treatments for dogs

We consulted two veterinarians for advice regarding the treatment and prevention of fleas and other parasites in dogs. This information guided our selection of the best flea treatments for dogs, but our experts did not endorse any of the products included in this guide unless explicitly quoted.

We also conducted research using the quick product reference guide published by the independent, nonprofit Companion Animal Parasite Council. This helpful reference includes all FDA- and EPA-approved parasite control products for small animals along with each product's active ingredients, directions for how to use it, and which parasites it controls.

Flea medicine for dogs FAQs Do dogs really need flea and tick medicine?

Yes. Not only are fleas and ticks a big nuisance, they also carry diseases that can make dogs extremely ill. Although you may be tempted to use parasite preventives only in spring and summer, fleas, ticks, mosquitoes, and intestinal parasites are resilient. Veterinarians recommend that dogs stay on broad-spectrum parasite preventives all year.

What are the types of flea and tick medicine for dogs?

Flea and tick medicines are available as oral and topical products, collars, and shampoos. Oral products are chewable tablets, while topical products are ointments that go directly on the skin. Flea collars have fallen out of favor because they are less effective than oral and topical treatments. Shampoos are also less effective and do not provide long-lasting flea protection. These medicines are available over the counter or by prescription and contain different active ingredients to kill and repel fleas and ticks. 

What do vets recommend to get rid of fleas?

Getting rid of fleas can take several days to weeks. Veterinarians recommend a multipronged approach: Kill the existing fleas, prevent new infestations, and treat the environment, both indoors and outside. If you have multiple pets, treat them at the same time. Treating inside your home involves vacuuming where flea eggs and larvae like to hide, such as cracks and crevices, and washing bedding in hot water. Treating outdoors involves eliminating any areas where fleas could hide, such as piles of leaves and tall grass. If this process seems daunting, you can hire a pest control service.

What is the most effective flea and tick treatment for dogs?

There is no single treatment that works best for all dogs. The best flea and tick treatments for dogs vary in many ways, including how many parasites they target, active ingredients, safety restrictions, and how long they're effective. The most desirable treatments provide long-lasting protection, target adult fleas as well as eggs and larvae, and are effective against other parasites, such as heartworm and intestinal worms. Your veterinarian can help you select the most appropriate product for your dog.

What kills fleas permanently?

To eliminate fleas permanently, you'll need to do more than kill adult fleas. The other developmental stages, egg and larvae, must also be eliminated. Products that kill the early stages of fleas are the most effective. Year-round flea and tick treatment is also crucial to preventing future infestations. It may take several weeks before all the fleas are gone.

Which is better, NexGard or Frontline?

Both NexGard and Frontline kill fleas at all life stages, plus ticks. Both treatments have their advantages. There are several Frontline products: Shield, Plus, and Gold. Our top choice for an OTC flea preventive is Frontline Plus, which also protects against chewing lice and helps control sarcoptic mange infestations. Compared to Frontline Plus, NexGard kills fleas more quickly (4 hours versus 12 hours) and ticks (24 hours versus 48 hours). For this reason, NexGard is a better choice for preventing the transmission of Lyme disease from ticks. Some veterinarians also use NexGard to treat mange.

What is the safest flea and tick medicine for dogs?

Flea and tick medicines are FDA-approved to be safe and effective. However, these medicines also have safety restrictions depending on age, weight, and whether a dog is pregnant or nursing. Some treatments also have safety warnings for dogs with a history of seizures or other neurologic disorders. As you evaluate flea and tick medicines, check the label to ensure it's safe for your dog. 

What is the difference between prescription and OTC flea medicine?

Some flea control products are sold over the counter, while others require a prescription. Prescription products typically cost more than OTC treatments because they protect against more parasites, including heartworms. However, OTC options can still provide effective, long-lasting treatment against fleas and other parasites.

Can I get flea and tick medicine without a vet prescription?

Yes, OTC treatments are available without a prescription. These medicines usually do not protect against as many parasites as prescription flea and tick products.

Do flea collars work?

Yes. Flea collars work but are generally less effective than topical or oral treatments. Seresto Flea and Tick Collar for Dogs provides eight months of protection against adult fleas, flea larvae, ticks, and mange mites. Lay recommends flea collars for dogs that cannot tolerate topical or oral flea products. 

Is Seresto harmful to dogs?

In March 2021, USA Today and the Midwest Center for Investigative Reporting published a report alleging that the Seresto flea collar is linked to thousands of adverse incidents in pets and humans. To date, 2,500 pet deaths have been allegedly linked to the collar.

Elanco published a statement defending the collar's safety and efficacy. The American Veterinary Medical Association (AVMA) and Pet Poison Hotline followed suit. The EPA recommends pet owners read the entire label before using any flea collar and follow all directions carefully. Your veterinarian can provide additional safety guidance. Purchase a Seresto collar only from a reputable online retailer, brick-and-mortar store with a guarantee program, or your veterinarian. To verify product authenticity, call Elanco product support at 800-422-9874. If your pet has an adverse reaction, immediately remove the collar and call your veterinarian. Tim Carroll, EPA's press secretary, advises pet owners to contact the  National Pesticide Information Center and report adverse reactions to the EPA.

How can I tell if my dog has fleas?

Fleas are hard to see with the naked eye. Look for signs of a flea infestation on your dog, including nonstop biting, scratching, or licking and red, irritated skin. Flea dirt, a rust-colored mixture of blood meal and dried feces, is a telltale sign of fleas and can be found in places your dog spends time, such as their bed. Running a flea comb against the direction of your dog's fur can pick up the dirt. You can often see it on your dog in hard-to-reach places like the base of the tail, middle of the back, and groin. Other signs include pale gums, which are a sign of anemia, and patches of hair loss. 

Pets, If You Are On These Flea And Tick Medications, Beware Of Seizures

The medication that you're giving me can do what? (Photo: Getty Images)

Fleas and ticks can get on your pet's nerves. But apparently so might some medications to get rid of these pests.

The U.S. Food and Drug Administration (FDA) has issued a warning that medications in the isoxazoline class such as Bravecto, Credelio, Nexgard and Simparica may do more than just combat flea or tick infestations. These medications have the potential of causing seizures, ataxia, muscle tremors, or other neurological problems in your pets. Ataxia is a condition in which your pets can't control their muscle movements and thus may have trouble walking, balancing, or speaking. Of course, you may not necessarily be able to tell if your pet is having difficulty speaking. But the FDA warning means that you should be on the lookout for any struggles that your pet may be having after taking these medications.

It is not a complete surprise that these medications may affect your pet's nervous system. After, these medications act by messing with the nervous systems of fleas and ticks. Your pet, typically a dog or cat since alpacas are not common household pets, will first munch on the medication. The medication then gets into your pet's bloodstream. There the medication may enter any flea or tick that is actively feeding on your pet's blood.

That's where the fun begins for the fleas and ticks. As with humans, nerves in fleas and ticks acts like wires conducting electrical signals that control movement and other functions. These electric signals normally jump from nerve to nerve via neurotransmitters such as gamma-aminobutyric acid (GABA) and glutamate. However, the medication can interfere with the actions of these neurotransmitters, impeding the transmission of these electrical signals. This can then paralyze and kill the fleas and ticks, in essence short-circuiting their nervous systems. Dead fleas and ticks also can't lay eggs and reproduce. 

Pictured here is a flea in dog fur. (Photo: Getty Images)

With this mechanism of action, it shouldn't be a complete surprise that the medications may also screw with your pet's nervous system. But before you freak out about the medication paralyzing and killing your pets, keep in mind that the medications are still FDA-approved for use in pets, assuming that your pet is not a giant flea. Fleas and ticks are thankfully much smaller than dogs and cats. So they tend to be more susceptible to smaller amounts of the medications. They also have different anatomy and physiology.

Note that the FDA didn't say how common such side effects in dogs and cats may be. The FDA only issued a warning and asked manufacturers to include the warning on their labels. Currently, the risk nay not be high since the FDA did not advise against using the medications for your dogs and cats.

Don't start that flea and tick medication on me without consulting a veterinarian. (Photo: Getty... [+] Image)

So, for you fleas and ticks out there hoping that the FDA would pull these medications from the market, sorry that's not going to happen. If you are a human, this news may not change your flea and tick control methods but don't use these medications on your pet without guidance from a veterinarian. Keep your veterinarian informed about any changes in your dog's or cat's behavior while on these medications. If you are a veterinarian, make sure that pet owners are aware of these potential side effects and discuss flea and tick control options if they are concerned. And if you are a dog or cat, woof, woof, woof, and meow, meow, meow.

VA Continues 'approved' Experiments On Dogs, Cats And Monkeys After Congress Orders An End To Live-animal Tests By 2026

A hospital staff member took this 2019 photo of a cat used in experiments at the Louis Stokes Cleveland VA Medical Center. Tests involved placing electrodes in the cat's bladder and using a device to stimulate urination. The VA in 2024 is seeking to implant wires and sensors in the legs and backs of cats in a separate experiment to test an implant for translating signals from a prosthesis to the nervous system. (White Coat Waste Project)

WASHINGTON — Researchers from the Department of Veterans Affairs will implant pacemakers in the hearts of 54 dogs that will be euthanized at the end of the tests and surgically embed wires and sensors into the backs and legs of cats in separate experiments that the VA plans to conduct on live animals in 2024, according to agency documents.

Though the Department of Veterans Affairs is under order by Congress to phase out live animal experiments using cats, dogs and primates "with limited exceptions" by 2026, the agency continues to support live-animal research at VA facilities across the U.S., according to the VA.

More than 62,000 cats and dogs are in U.S. Labs for live animal experiments run by government agencies, colleges and universities, and private companies, according to the Humane Society of the United States, a nonprofit organization that focuses on the welfare of animals.

The VA has been phasing out live animal testing on dogs, cats and primates since 2018.

Terrence Hayes, the VA press secretary, said the agency is assessing a new congressional directive adopted in March to eliminate the live-animal tests "with limited exceptions" within two years.

"VA is reviewing the recently signed fiscal year 2024 appropriations law to ensure any implementation of the new provisions fully meet congressional intent, including using of funding, program requirements and reporting to our congressional partners," he said.

A provision requiring the VA to end live animal research is part of the Consolidated Appropriations Act, signed into law March 9. The legislation requires the VA to provide a plan for ending the tests within 90 days of the bill's enactment.

In 2024, the VA's list of "approved research" on live animals includes two separate experiments using dogs at the Richmond VA Medical Center in Virginia.

The experiments involve implanting pacemakers in the hearts of dogs to induce extra heartbeats that disrupt the regular heart rhythm, causing a sensation of fluttering in the chest. The purpose is to measure deteriorating heart muscle and heart failure caused by the extra heart beats.

The dogs will undergo open heart surgery to implant a pacemaker device and a radio telemetry system. Catheters also will be positioned on the heart surface, according to the project description.

Fifty-four dogs will be used in the experiment, after which "most will be euthanized," according to VA documents.

Dogs not euthanized will be granted a four-week recovery at which time the pacemakers will be disabled, and the animals further studied. Those dogs also will be euthanized at the conclusion of the tests.

The White Coat Waste Project, a nonprofit watchdog group, said records obtained by the organization under the Freedom of Information Act show no dogs are currently confined at the Richmond VA Medical Center or being used there for heart experiments.

A separate VA experiment using cats is approved for 2024 for the Louis Stokes VA Medical Center in Cleveland for testing the durability of implanted medical devices to stimulate nerve sensation in patients who have undergone amputations.

"New prosthetic technology for amputees can restore natural sensations," according to the project proposal published by the National Institutes of Health.

Funding through September for the experiments is about $270,000, according to information the VA published on its website.

The experiments involve surgically embedding wires and sensors into the legs and backs of cats, according to documents obtained by the White Coat Waste Project.

The procedures risk paralysis and death in the cats, which is counter to directives by Congress for restricting these types of tests, said Justin Goodman, senior vice president of White Coat Waste Project.

The experiment is to test a miniaturized implant that translates electrical signals from a prosthesis to the nervous system, which could allow veterans who lost a limb to achieve a better sense of balance and motion in digits and joints, Hayes said.

He described the experiments as safe and said the cats will be placed into adoptive homes at the conclusion of the research in six months.

The VA also has approval in 2024 to continue experiments on dozens of rhesus macaque monkeys for measuring treatment outcomes for spinal cord injuries.

The experiment at the VA San Diego Health Care System involves damaging a monkey's spinal cord in surgical procedures.

The monkey then undergoes "multiple major survival surgeries" along with stem cell therapy to address injuries and observe recoveries.

"Each of these surgeries will add to the body of knowledge we can gain about recovery from spinal cord injury," according to the project description on the VA website.

"This research is to explore the possibility that neural stem cells can be used to help bridge the damaged tissue and restore communication across the site of the injury," according to the project description.

The experiment identifies the use of restraint chairs for behavioral testing to force monkeys recovering from spinal cord injuries to use the hand with limited use to perform tasks. The monkeys also are expected to walk on treadmills and retrieve food to improve function, according to the project description.

The experiments using the monkeys are being conducted in conjunction with other agencies including University of California-Davis, which has one of the biggest primate laboratories in the country, Goodman said.

Animals are purchased from breeders licensed to sell dogs, cats, primates and other animals to laboratories for use in live-animal experiments.

Goodman said his organization objects to the VA using taxpayer dollars to purchase animals and submit them to painful experiments. He said animals often are euthanized and dissected at the end of the research, as part of the study.

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