Prescription flea and tick medicine for dogs

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There are many safe and effective flea control products for dogs, either available with a veterinarian's prescription or sold over the counter. Many products kill and prevent other parasites, too, including ticks, heartworms, intestinal parasites, mites, and biting flies.

Choosing a safe and effective flea and tick medicine for dogs can be complicated. There are many products available and they're all a little different. My background taught me a lot about parasite prevention and the various flea control products available today. I spent eight years working as a veterinary assistant in animal hospitals followed by two more decades as an editor for magazines in the pet and veterinary fields. Over the years, I've treated countless dogs for fleas, including my own dogs.

For this guide, I used the quick product reference guide published by the independent, nonprofit Companion Animal Parasite Council to research products. I selected products based on safety, the number of parasites targeted, products' ease of use, and the minimum age the product can be used. Jump to the end of this guide to read more about our selection criteria. For additional guidance about treating and preventing fleas on dogs, I consulted with two veterinarians.

Before choosing a flea preventive for your dog, talk to your veterinarian who can advise you on what type of product might be best depending on your dog's temperament and lifestyle, and what parasites are most prevalent in your location. Learn more about how Insider Reviews tests and researches pet products.

These are the best flea and tick prevention for dogs in 2021

Best topical flea preventive overall: Advantage Multi for Dogs, $121.79 at Chewy
With just one easy monthly application, Advantage Multi for Dogs treats, controls, and prevents more parasites than any other topical product. 

Best OTC topical flea preventive for dogs: Frontline Plus for Dogs, $61.19 at Chewy
Available without a prescription, Frontline Plus for Dogs kills adult fleas, flea eggs, flea larvae, ticks, and chewing lice on contact.

Best oral flea control product for dogs: Simparica TRIO, $163.53 at Petco
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. 

Best flea control product for young puppies: Capstar for Dogs, $33.29 at Chewy
Capstar for Dogs is safe for puppies as young as 4 weeks old and starts killing fleas within 30 minutes.

Best flea collar for dogs: Seresto Flea and Tick Collar for Dogs, $62.98 at Chewy
The Seresto Flea and Tick Collar for Dogs offers eight months of protection against fleas and ticks in all life stages.

The best topical flea preventive overall

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

Pros: Kills and prevents six types of parasites including heartworm, once-monthly treatment, easy to administer, safe for use in puppies 7 weeks and older and weighing at least 3 pounds

Cons: Does not kill ticks, not labeled for use in puppies younger than 7 weeks or breeding, pregnant, or nursing dogs

No preventive covers every single parasite that could harm your dog, but Advantage Multi for Dogs comes close. Advantage Multi is a topical spot-on product that contains the active ingredients imidacloprid and moxidectin to 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. As with all medications that prevent heartworm, your dog needs a heartworm test prior starting Advantage Multi and annually thereafter.

Advantage Multi is easy to use: Just apply every 30 days 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 with some of the other topical preventives, you do not need to wear gloves to apply Advantage Multi. If you get the product on your hands, simply wash with soap and water. For the first 30 minutes after application, keep dogs from licking the application site, either on themselves or other treated dogs in the house. Children should not touch the application site for two hours after application.

Advantage Multi does not prevent ticks. If ticks are a concern and you wish to use a topical, consider another product like Frontline Plus for Dogs, Bravecto Topical for Dogs, or K9 Advantix II.

The best OTC topical flea preventive

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

Pros: Kills adult fleas, flea eggs, flea larvae, all life stages of ticks and chewing lice for one month; safe for use in dogs and puppies at least 8 weeks of age that weigh at least 5 pounds; safe for use in breeding, pregnant and nursing dogs; fleas don't have to bite for it to work

Cons: Not recommended for puppies younger than 8 weeks of age; does not prevent any parasites other than fleas, ticks, and chewing lice

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 been used and trusted by pet owners for more than two decades. Parasites die on contact — they do not have to bite your dog for Frontline Plus 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. S-methoprene prevents flea eggs, larvae, and pupae from developing. Completely breaking the flea life cycle can sometimes take up to a month of consistent use, especially if your dog is heavily infested, because flea eggs can be in your home but not on your dog.

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

The best oral flea control product

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. 

Pros: Protects against more parasites than any other oral product, once-monthly treatment, safe for dogs and puppies 8 weeks of age and older weighing at least 2.8 pounds, easy to administer alone or in food

Cons: Not labeled for use in puppies younger than 8 weeks or breeding, pregnant, or nursing dogs

Our pick for best oral flea control product for dogs is Simparica TRIO, a chewable tablet that is fast-acting and kills more parasites than any other oral product. Simparica TRIO 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 a spot-on. 

"Oral products have the benefit of broad coverage to reach every spot of skin without the chance of the product being washed off," Crumley said. "Rarely, a pet will have mild intestinal upset with any oral product. If that occurs then that pet will do better with one of the system-absorbed topical choices."

The liver-flavored flavored chewable tablets can be given with or without food once a month. In addition to providing a full month of protection against the most parasites of any other oral product, Simparica TRIO is also labeled for use in some of the youngest and smallest puppies and dogs.

Simparica TRIO contains three ingredients: sarolaner, moxidectin, and pyrantel. It requires a prescription from your veterinarian, as well as a current negative heartworm test. Simparica TRIO should be used with caution in dogs with a history of neurologic disorders such as seizures.

The best flea control product for young puppies

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

Pros: Safe for puppies 4 weeks of age and older weighing at least 2 pounds, safe for pregnant and nursing dogs, fast-acting treatment starts killing adult fleas within 30 minutes, easy to administer alone or in food, can be used with other flea control products, available without a prescription

Cons: Does not offer long-term protection, does not kill flea larvae or flea eggs, does not prevent any parasites other than fleas

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 product, puppies must be at least 8 weeks old and sometimes older. 

Fleas should be eliminated as quickly as possible for heavily infested dogs, especially young puppies. The active ingredient in Capstar, nitenpyram, works within 30 minutes and kills greater than 90% of adult fleas on dogs in as little as four hours.

Capstar's protection against fleas lasts only 24 hours, but it is safe to give daily if necessary. This 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 offers a month or more of protection once the puppy is old enough.  

The best flea 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 and this story is still developing. Read "Can a flea collar harm your dog?" for more details. Always speak to your veterinarian if you have concerns before using a product and only purchase Seresto collars from authorized retailers.

Pros: 8 months of continuous protection against adult fleas, flea larvae, four species of ticks, chewing lice, and mange mites; lightweight and easy to wear; adjustable for dogs of all sizes; parasites don't have to bite for it to work; safe for puppies 7 weeks of age and older

Cons: Not recommended for puppies younger than 7 weeks of age, children should not play with the collar, adjusting size can be tricky

Flea collars were once prevailing options for flea control, but most traditional flea collars don't offer the same level of protection as topical and oral preventives. One noteworthy flea 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 preventives and oral preventives are the easiest and most effective form of flea control for dogs, but the Seresto collar might be a good option in certain situations.

Lay said that traditional flea and tick collars are generally not very effective, and she has even seen allergic reactions and other issues with some of them. However, she has found the Seresto collar to be both safe and effective.

"I personally used a Seresto collar with my dog for years when we lived in Chattanooga—hiking in the mountains and camping amongst the ticks," Dr. Lay said. "I often recommend it to clients who have pets that don't tolerate topical or oral flea/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 ensure your dog will not be harmed if the collar gets caught on something.

The Seresto Flea and Tick Collar for Dogs contains imidacloprid and flumethrin, which 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. The collar is water-resistant and can stay on the dog even during swimming or bathing.

What else we considered

• Bravecto Chews for Dogs: Unlike most oral preventives, which must be given monthly, one dose of prescription-only Bravecto kills fleas for three months and ticks for up to two months. Bravetco doesn't kill any parasites other than fleas and ticks. It cannot be used in puppies younger than 6 months old and should be used with caution in dogs with a history of neurologic disorders such as seizures.
• Bravecto Topical for Dogs: With one application, this topical product kills fleas for three months and ticks for up to two months. Bravetco doesn't kill any other parasites and cannot be used in puppies younger than 6 months old. It requires a prescription from your veterinarian and should be used with caution in dogs with a history of neurologic disorders such as seizures.
• Comfortis: Comfortis is an oral product that kills adult fleas and prevents flea infestations for one month. It doesn't kill any parasites other than fleas and cannot be used in puppies younger than 14 weeks old. Comfortis requires a prescription from your veterinarian.
• Credelio: Credelio is an oral product that kills adult fleas and ticks and prevent flea and tick infestations for one month. It doesn't kill any other parasites and requires a prescription from your veterinarian. It should be used with caution in dogs with a history of seizures.
• K9 Advantix II: This is a topical spot-on product that repels and kills fleas, flea eggs, flea larvae, ticks, mosquitoes, and lice for one month. It also repels biting flies. We gave Frontline Plus for Dogs a slight edge over K9 Advantix II because it is effective against fleas, flea larvae, and flea eggs for up to three months (though if ticks are an issue, monthly application is required). Additionally, you must seek the advice of a veterinarian before using K9 Advantix II for breeding, pregnant, and nursing dogs.
• NexGard Chewables for Dogs: NexGard is an oral product that kills adult fleas and ticks and prevents flea infestations for one month. It requires a prescription from your veterinarian and should be used with caution in dogs with a history of seizures.
• Revolution for Dogs: Revolution is a monthly topical product that kills adult fleas and prevents flea eggs from hatching. It also prevents heartworm, treats and controls ears mites, and kills American dog tick, but it does not prevent any intestinal parasites, unlike Advantage Multi for Dogs. However, Advantage Multi does not kill ticks. Revolution requires a prescription from your veterinarian and a current negative heartworm test.
• Trifexis:Trifexis is a monthly oral product that kills adult fleas, prevents flea infestations and heartworm, and treats and controls hookworms, roundworms, and whipworms. We gave Simparica TRIO a slight edge over Trifexis because it also kills ticks, mange mites, and chewing lice — though it does not kill whipworms. Trifexis requires a prescription from your veterinarian and a negative heartworm test and should be used with caution in dogs with a history of seizures.

How we selected products

We consulted with two veterinarians for advice regarding the treatment and prevention of fleas and other parasites in dogs. Although this information guided us in our product selection, our veterinary experts did not endorse any of the products included in this guide unless explicitly mentioned in direct quotes.

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

Here are the main attributes we looked for:

Safety and efficacy: Only FDA- or EPA-approved products were considered for this guide.

Number of parasites treated: In general, the more parasites a preventive product covers, the higher it was rated. "Parasites cause skin disease just by their presence and they carry diseases, too," said Crumley. "Small puppies can actually become anemic from the amount of blood these parasites steal from their growing bodies."

The exceptions are Capstar, which is the only treatment available for puppies younger than 6 weeks and our over-the-counter pick, Frontline Plus, which treats fleas, ticks, and lice. Products that treat heartworm always require a prescription.

Ease of use: Products were rated lower if they were more complicated to use than a similar product. For instance, products ranked lower if the pet owner must wear gloves to apply the product or if children and pets need to be kept away from the treated animal for a specified amount of time.

Minimum age and weight: When comparing similar products, higher ratings went to preventives that can be used in younger animals (for instance, puppies 7 weeks of age instead of 12 weeks of age).

Types of flea control products

Here are the most common flea control products for dogs and how they work:

• Topical preventives: Also called spot-on products, topical preventives are great for killing fleas and preventing flea infestations. As they dry, they spread across the entire body or may be absorbed through the skin into the pet's system, leaving no residue behind. They are usually applied to the skin in one spot on the back of the neck once a month, although a few last longer than 30 days. "Some dogs with sensitive skin may react to a topical product," Crumley said. "Dogs who swim frequently or are bathed frequently will lose the benefit of the topical product that stays on the surface of the skin."
• Oral flea control: Oral flea control products, or "flea pills," are given to your dog by mouth to kill fleas. Some oral flea control products kill fleas for up to a month or longer; others must be given more frequently to continue killing fleas, as often as once a day.
• Flea collars: These are worn around the neck, where they deliver flea preventive medication to your dog's skin and coat. Some flea collars deliver preventive medication for a longer period than topical applications, making them a good choice for dog owners who don't want to have to apply something every month.
• Flea shampoos: These kill fleas that are currently on your dog. We do not recommend flea shampoos in place of other preventives since topical spot-ons and oral products are easier to use and more effective.
• Flea spray: These are applied to the skin and coat. We do not recommend flea sprays since topical spot-ons and oral products are easier to use and more effective.

Can a flea collar harm your dog?

The safety of flea and tick collars has been widely discussed recently, specifically the bestselling Seresto Flea and Tick collar, which was developed by Bayer and is now sold by Elanco Animal Health. On March 2, 2021, USA Today and the Midwest Center for Investigative Reporting published a report alleging that the Seresto collar has been linked to thousands of adverse incidents, including pet deaths and harm to humans.

In April 2021, the Center for Biological Diversity (CBD) filed a legal petition urging the U.S. Environmental Protection Agency (EPA) to cancel the registration of the Seresto flea and tick collar. A week later, the American Veterinary Medical Association (AVMA) published an article addressing the controversy about the collar. According to the AVMA, Seresto's "manufacturer has defended the collars as safe and effective, and veterinary experts say they have seen no cause for alarm."

Elanco published a statement on its website in response, saying that the media coverage "misleading" and that the company stands by the product. "All data and scientific evaluation used during the product registration process and through Elanco's robust pharmacovigilance review supports the product's safety profile and efficacy," the statement reads.

On July 12, the EPA announced that it is seeking public comment on the petition from the CBD requesting that the EPA cancel the registration of Seresto. Public comments will be collected for 60 days. "In addition, EPA is reviewing the additional information received by Elanco and Bayer and will use it to evaluate if the continued registration of these pet collars still meets the legally required standard of no unreasonable adverse on the environment, taking into account the economic, social, and environmental costs and benefits of the use of the pesticide," said Tim Carroll, deputy press secretary for the EPA. "Upon completing the analysis and assessment, EPA may take further action, if needed."

What pet owners need to know

If you have questions about the Seresto Flea and Tick Collar or any other flea-control product, ask your veterinarian for advice. Regardless of what type of flea-control product you choose for your dog, the EPA recommends pet owners read the entire label before using the product, follow all directions carefully, and monitor pets after treatment.

There are also reports of counterfeit Seresto collars on the market, particularly through online retailers. Petco and Petsmart, major suppliers of pet products, told Insider that they purchase Seresto collars directly from the manufacturer, Elanco. It's important to purchase from a reputable website, brick-and-mortar store with a guarantee program, or for the most assurance, directly from your veterinarian. Before placing a Seresto collar on your pet, we also recommend that pet owners call Elanco product support (800-422-9874) to verify the authenticity of the product's serial number.

If you suspect that your pet is having an adverse reaction to a flea collar, immediately remove the collar and call your veterinarian. Carroll also advises pet owners to contact the National Pesticide Information Center, which is an EPA information-sharing partner with staff who are specially trained to respond to pesticide exposure incidents, as well as to report adverse reactions from flea collars and topical treatments on the EPA's website.

What you should know about fleas in dogs

If your dog has fleas, you want to get rid of them as quickly as possible. Dogs can pick up fleas anywhere, including your yard, local parks, the groomer, veterinary clinic, and boarding facilities, but even dogs that spend a lot of time indoors can get fleas if they hitchhike indoors on your clothes or shoes. Dogs that hike, camp, and explore wilderness areas can pick up both fleas and ticks.

What are the health risks to your dog?

Fleas are more than just a nuisance. These parasites can pose a threat to your dog's health. A severe flea infestation can seriously damage your dog's skin, induce an allergic reaction, or cause them to become anemic from blood loss. Fleas are also responsible for transmitting parasites like tapeworms.

"Regardless of where you live in the country, I promise there's a flea or tick disease out there," Lay said. "Fleas and ticks can really make a pet sick and what's worse, they often carry other bad guys along with them." These parasites can transmit things like Lyme disease, Rocky Mountain spotted fever, cat scratch fever, and even the plague.

How to check a dog for fleas

Signs of fleas in dogs include scratching, skin irritation, and the presence of dark red or black specks on your dog's skin, fur, bedding, or furniture. These specks, about the size of grains of black pepper, are called "flea dirt" and are flea feces, or digested blood.

Back when I worked in the veterinary hospital, I learned a handy trick to help find out if those little specks are regular dirt or flea dirt. Scoop some onto a damp paper towel. If the paper towel turns red, it's flea dirt.

To check your dog for fleas or flea dirt, run a flea comb (a small, very fine-toothed comb) through your dog's coat or part the hair with your fingers to examine the skin. If you find any live or dead fleas or flea dirt, your dog has a flea infestation.

What to consider when purchasing flea control products

Prescription vs. over-the-counter flea prevention and control

Some flea control products are sold over the counter. Other products require your veterinarian to write a prescription. You can purchase prescription products directly from your veterinarian or from online pet pharmacies and certain pet supply stores like Chewy, Petco, and Petsmart.

Prescription flea control products cost more than OTC products because they protect against more parasites, most importantly, deadly heartworms. Dogs must test negative for heartworms before starting a heartworm prevention product. Giving a heartworm-positive dog a prevention medication can cause rare but potentially very serious and sometimes fatal complications. You also want to know if your dog has adult heartworms because the preventive medication will not kill them — it only kills the larval stages of the heartworm.

Use parasite preventives year-round.

You might be tempted to only use parasite preventives in spring and summer, but don't underestimate the resilience of fleas, ticks, mosquitoes, and intestinal parasites. Veterinarians recommend that all dogs stay on broad-spectrum parasite preventives all 12 months of the year.

Heartworm treatment is long, costly, and dangerous. Dogs with adult heartworms can die even if treatment is initiated. This is why veterinarians recommend using a year-round heartworm preventive for all dogs, regardless of what part of the country they live in. Veterinarians also recommend year-round intestinal parasite prevention for all dogs.

Flea shampoos are usually unnecessary.

Decades ago, people might have just used a flea shampoo containing pesticides to kill fleas, but flea shampoos are no longer the gold standard. Veterinarian-recommended topical and oral flea control products are far more effective than flea shampoos.

"Most flea and tick shampoos are harsh to the skin and only remove the parasites present at the time of the bath," Crumley said. "Most of them are not effective at treating ticks, either. The residual effect might last 24 or 48 hours at most, and then the nasties will be back."

Lay notes that some pet owners want to use flea shampoos instead of veterinarian-approved oral or topical preventives because shampoos cost less. However, this approach could backfire.

"Besides not really preventing and being as effective at breaking the infestation/cycle, they can also sometimes cause additional reactions and allergies," Lay said. "They are not meant to take the place of preventive options, so consult with your veterinarian on when and how to use them."

Be wary of natural flea control products.

Both veterinarians we consulted do not recommend natural products in place of veterinarian-recommended topical and oral flea control products. While they 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," said Crumley.

If you also have cats at home, avoid natural flea control products containing essential oils as some of them can be toxic to cats.

Some flea products are dangerous to cats.

If you have cats as well as dogs, it's important to understand that any product labeled for use in only dogs should never be used on a cat. Some ingredients that are well-tolerated by dogs can be toxic to cats. Any dog-only flea product can be harmful to cats, but they are especially sensitive to pyrethrins. If you're looking for a product that's safe for felines, read our guide to the best flea control products for cats.

Our sources

Jackie Brown

Freelance Writer

Pet expert Jackie Brown has spent 20 years following her passion for animals as a writer and editor in the pet industry. Her expertise includes dog and cat health, care, nutrition, feeding, grooming, behavior, and training. Jackie writes regularly for pet and veterinary industry media, including Dogster and Catster magazines, The Spruce Pets, Great Pet Care and All About Cats.   She is a contributing writer for "National Geographic's Complete Guide to Pet Health, Behavior, and Happiness" and author of the book "It's Raining Cats and Dogs: Making Sense of Animal Phrases." She is contributing editor of Dogster and Catster magazines, and the former editor of numerous pet magazines, including Dog World, Natural Dog, Puppies 101, Kittens 101, and the Popular Cats Series.   Jackie earned her bachelor of arts degree in English from the University of California, Irvine. Prior to starting her career in publishing, she spent eight years working in veterinary hospitals where she assisted veterinarians as they treated dogs, cats, rabbits, pocket pets, reptiles, birds, and one memorable lion cub. She lives in Southern California with her husband, two sons, and miniature poodle Jäger, who she grooms at home.  Jackie can be reached at jackiebrownwriter.wordpress.com. Learn more about how our team of experts tests and reviews products at Insider here.

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