# Flea and Tick Prevention (2026): EPA vs FDA Products, and the Dog Products That Can Kill Cats > Who regulates each flea and tick product, EPA or FDA, the dog-only products that can kill a cat, what EPA found on Seresto, and five over-the-counter options. - Source: https://petprooflab.com/grooming-health/flea-and-tick-prevention - Publisher: PetProofLab (https://petprooflab.com) - Published: 2026-09-28 - Category: grooming-health - Tags: flea and tick prevention, flea treatment, EPA, FDA, permethrin, cats, Seresto, isoxazoline - Method: picks chosen from Amazon listings and brand specs; not hands-on tested; current Amazon prices are on the page; content checked 2026-09-28. - Quick answer: Over-the-counter spot-ons and collars such as Frontline Plus, Advantage II, K9 Advantix II and Seresto are pesticides registered by the EPA; the chews and topicals in the isoxazoline class (Bravecto, NexGard, Simparica, Credelio) are FDA-approved animal drugs to choose with your vet. Check the species and weight on every box. K9 Advantix II contains 44 percent permethrin and its EPA label says: do not use on cats, may be fatal. The Companion Animal Parasite Council recommends treating dogs and cats year-round. ## Key takeaways - EPA-registered products carry an 'EPA Reg. No.' on the label; FDA-approved drugs are chosen with your vet. The agencies split them by whether the chemical stays on the skin or is absorbed into the blood. - Never put a dog product on a cat. EPA found that cats exposed to dog products were 'an important problem' in spot-on incidents. - K9 Advantix II (permethrin) is labeled 'DO NOT USE ON CATS – MAY BE FATAL,' with cats kept away from a treated dog for 24 hours. - EPA reviewed Seresto incident reports and kept the collar registered in 2023, with new label warnings and a five-year limit on its approval. - The FDA warns that isoxazolines (Bravecto, Credelio, NexGard, Simparica) have been linked to tremors, ataxia and seizures in some pets, while still calling them safe and effective. - CAPC recommends year-round flea and tick control for all dogs and cats, for life. ## Products (chosen from listings, not tested) 1. **FRONTLINE Plus for Dogs, Medium Breed 23 to 44 lb, 3 Doses** (details: https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B0002J1FN0) — An EPA-registered monthly spot-on for dogs that covers fleas at every stage and ticks. - Pros: EPA Reg. No. 65331-5; fipronil and (S)-methoprene, per the EPA label; Kills adult fleas, flea eggs, flea larvae, ticks and chewing lice, per the listing; Separate weight bands for dogs; for dogs and puppies 8 weeks or older - Cons: Label reads 'USE ON DOGS ONLY'; buy the cat version for a cat 2. **FRONTLINE Plus for Cats and Kittens, 3 Doses** (details: https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B0002J1F76) — A cat-labeled spot-on that also covers ticks, for a cat that goes outdoors. - Pros: EPA Reg. No. 65331-4 on the cat label; fipronil and (S)-methoprene; For cats and kittens 8 weeks or older weighing 1.5 lb or more, per the listing; Kills adult fleas, flea eggs, flea larvae, chewing lice and ticks, per the listing - Cons: The listing claims no heartworm protection; some FDA-approved prescription products also prevent heartworm 3. **Advantage II Small Cat, 5 to 9 lb, 2 Doses** (details: https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B00LWLTXVS) — A flea-only spot-on sized for small cats, labeled for cats. - Pros: EPA Reg. No. 11556-151; imidacloprid and pyriproxyfen, per the EPA label; Kills adult fleas, flea larvae and flea eggs through contact; kills fleas within 12 hours, per the listing; For cats 8 weeks and older; separate sizes for small and large cats - Cons: Fleas only: the listing claims no tick protection 4. **K9 Advantix II Large Dog, 21 to 55 lb, 2 Doses** (details: https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B00N7DEBN4) — Dog-only: a strong choice for a dog in tick country, and the wrong one in a house where a cat grooms or sleeps with the dog. - Pros: EPA Reg. No. 11556-143; permethrin, imidacloprid and pyriproxyfen, per the EPA label; Kills and repels fleas, ticks and mosquitoes, and protects against biting flies and lice, per the listing; For dogs 7 weeks and older; sold by Amazon.com - Cons: 44 percent permethrin; the label says do not use on cats, may be fatal, and keep cats away from treated dogs for 24 hours 5. **Seresto Flea and Tick Collar for Large Dogs over 18 lb** (details: https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B00B8CG602) — The long-lasting non-prescription option; watch your dog closely after putting it on and take it off at any sign of a reaction. - Pros: EPA Reg. No. 11556-155; flumethrin and imidacloprid, per the EPA label; Kills and repels fleas for 8 continuous months, per the listing; Release mechanism: the label says a trapped dog's own strength is usually enough to widen the collar - Cons: EPA required new adverse-event warnings in 2023 and limited the registration to five years while it keeps reviewing incident data For flea and tick prevention on a dog or a cat, the first thing to check is who regulates the product. Spot-ons and collars sold without a prescription, like Frontline Plus, Advantage II, K9 Advantix II and Seresto, are pesticides registered by the EPA, and the chews and topicals you choose with your vet, like Bravecto, NexGard, Simparica and Credelio, are FDA-approved drugs. The second thing is the species on the box, because some dog products can kill a cat. **How we chose:** we did not test these; we read each product's EPA label and listing, and kept only over-the-counter products sold by Amazon.com that were in stock on September 28, 2026. Prescription products are named in the text, not carded. ## Five over-the-counter products and who regulates them | Product | Regulator and number | Species | Active ingredients (per EPA label) | Amazon price | |---|---|---|---|---| | [Frontline Plus for Dogs](https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B0002J1FN0) | EPA Reg. No. 65331-5 | Dogs only | Fipronil, (S)-methoprene | see the current Amazon price on the page | | [Frontline Plus for Cats](https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B0002J1F76) | EPA Reg. No. 65331-4 | Cats only | Fipronil, (S)-methoprene | see the current Amazon price on the page | | [Advantage II Small Cat](https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B00LWLTXVS) | EPA Reg. No. 11556-151 | Cats only | Imidacloprid, pyriproxyfen | see the current Amazon price on the page | | [K9 Advantix II Large Dog](https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B00N7DEBN4) | EPA Reg. No. 11556-143 | Dogs only; **may be fatal to cats** | Permethrin 44%, imidacloprid, pyriproxyfen | see the current Amazon price on the page | | [Seresto Large Dog](https://petprooflab.com/grooming-health/flea-and-tick-prevention#product-B00B8CG602) | EPA Reg. No. 11556-155 | Dogs only (cats have a separate Seresto) | Flumethrin, imidacloprid | see the current Amazon price on the page | The registration numbers and ingredients come from the EPA-stamped labels for [Frontline Plus for Dogs](https://www3.epa.gov/pesticides/chem_search/ppls/065331-00005-20110728.pdf), [Frontline Plus for Cats](https://www3.epa.gov/pesticides/chem_search/ppls/065331-00004-20110726.pdf), [Advantage II Small Cat](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00151-20170627.pdf), [K9 Advantix II Large Dog](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00143-20220214.pdf) and [Seresto](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00155-20230713.pdf). All five were sold by Amazon.com when we checked. ## EPA-registered or FDA-approved: why it matters Two federal agencies regulate flea and tick products, and which one depends on how the product works. The EPA explains on its page about [regulating flea and tick products](https://www.epa.gov/pets/epas-regulation-flea-and-tick-products) that since the mid-1970s the two agencies have split oversight by "whether the chemical is systemically absorbed into the bloodstream (FDA oversight) or remains on the skin (EPA oversight)." In practice: - **EPA-registered pesticides** are most spot-ons, collars, sprays and shampoos sold over the counter. The label carries an EPA registration number. Before registering one, the EPA says it runs a human health risk assessment and an ecological risk assessment and "reviews companion animal safety data," and it re-reviews active ingredients at least every 15 years. - **FDA-approved animal drugs** include the chewable tablets and some topicals in the isoxazoline class. The FDA's [isoxazoline fact sheet](https://www.fda.gov/animal-veterinary/animal-health-literacy/fact-sheet-pet-owners-and-veterinarians-about-potential-adverse-events-associated-isoxazoline-flea) lists Bravecto, Bravecto Plus, Credelio, NexGard, NexGard Plus, NexGard Combo, Simparica, Simparica Trio and Revolution Plus. The FDA says a few are also approved to prevent heartworm and some treat intestinal worms; none of the five over-the-counter products here claims heartworm prevention. The line is blurring. The EPA says the agencies "now understand that many of the topically administered products currently regulated by EPA do not remain on the skin and are absorbed into the bloodstream," and in February 2023 the EPA and FDA released a joint whitepaper proposing to move oversight of flea and tick pet products from the EPA to the FDA. Nothing has moved yet. The regulator also tells you where to report a problem. The EPA's page on [controlling fleas and ticks on your pet](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) says to report adverse reactions "to EPA or FDA, depending on the label information." An EPA number means EPA and the maker; an FDA-approved drug goes to the maker or the FDA. ## Dog products that can kill cats This is the rule to tape to the cabinet. The EPA says: "Never apply dog products to cats, and visa versa, as some pesticides are more toxic to one species than another." The main culprit is permethrin, a pyrethroid used in many dog spot-ons. The ASPCA's poison control team writes, in [Not All Pets Are the Same](https://www.aspca.org/news/not-all-pets-are-same-why-species-matters-pet-toxins) (June 29, 2026), that products containing permethrin "are safe for use in dogs but can cause severe tremors and seizures in cats." In an earlier [ASPCA alert](https://www.aspca.org/news/feline-toxins-steer-clear-kitten-season), it notes that cats are sensitive "especially at concentrations found in dog topical products," and that exposed cats may show unsteadiness, muscle tremors and, in severe cases, seizures. K9 Advantix II is 44 percent permethrin. Its EPA label says, in capitals: "DO NOT USE ON CATS – MAY BE FATAL. Keep cats away from treated dogs for 24 hours. If applied to a cat or ingested by a cat, contact your veterinarian immediately." Elanco's own [K9 Advantix II page](https://yourpetandyou.elanco.com/us/our-products/k9-advantix-ii) repeats: "Do not use K9 Advantix II on cats." Most mistakes are not a cat getting the dog's tube on purpose; it is a cat cuddling or grooming a freshly treated dog. The EPA found the same thing when it studied spot-on incidents. Its [spot-on evaluation](https://www.epa.gov/pets/epa-evaluation-pet-spot-products-analysis-and-plans-reducing-harmful-effects) says its veterinarians "discovered that misuse or accidental exposure of cats to dog products was an important problem," that "cats can be harmed by dog products because they are more sensitive to certain pesticides," and that label warnings against using dog products on cats "are not working well enough." For dogs, it found small breeds were affected more than large breeds for some products, which is why dose depends so much on weight. Even the packaging can mislead. The EPA's page on [counterfeit pet pesticides](https://www.epa.gov/pets/avoid-counterfeit-pesticide-products-dogs-and-cats) warns about fakes with a missing EPA registration number or foreign labels under stickers, and says that if you find a dog product in a cat box, do not use it: "Some dog products are toxic to cats." That is one reason we list only products sold by Amazon.com or the maker's own store. **Key point:** in a house with a cat, choose a dog product without permethrin, or keep the cat fully away from the dog for as long as the label says. ## What EPA found on Seresto collars Seresto collars drew years of complaints, and the EPA answered them in July 2023. Its [Seresto review](https://www.epa.gov/pets/seresto-pet-collar-review) looked at 1,400 deaths reported from 2016 to 2020, which were 2 percent of all Seresto incidents in those years. Critical details were often missing. The only deaths the EPA found "probably" or "definitely" related to the collar "were associated with mechanical strangulation or trauma caused by the collar, often associated with a failure of the release mechanism." For other deaths it found no probable or definite link, and it said the rate of reported deaths "was similar to that for other pet products reviewed." It did not cancel the collar. Per the EPA's [2023 announcement](https://www.epa.gov/pesticides/epa-requires-additional-mitigation-measures-seresto-pet-collars), the EPA concluded that the collars "continue to meet EPA's standard" under federal pesticide law, but Elanco had to: - add label warnings listing the adverse effects reported, with instructions to remove the collar if they occur and how to report it; - split the registration into one for cats and one for dogs, and report incident and sales data every year; - evaluate changes to the release mechanism to prevent strangulation. The EPA also limited the collar's approval to five years so it can keep reviewing incidents, and it denied a petition to cancel it. The EPA says more common reported effects are itching in dogs and hair changes near the collar in cats, and that less common but more serious ones include convulsions and ataxia. The current dog label lists them in order of reporting frequency and ends: "Remove the collar if these symptoms occur and consult with your veterinarian." ## What the FDA says about Bravecto, NexGard, Simparica and Credelio The prescription side has its own warning. The FDA's [isoxazoline fact sheet](https://www.fda.gov/animal-veterinary/animal-health-literacy/fact-sheet-pet-owners-and-veterinarians-about-potential-adverse-events-associated-isoxazoline-flea) (current as of August 8, 2023) says these drugs "have been associated with neurologic adverse reactions, including muscle tremors, ataxia, and seizures in some dogs and cats," and that seizures may occur in animals without a prior history. It also says: "The FDA considers products in the isoxazoline class to be safe and effective for dogs and cats," and that most dogs and cats have not had neurologic reactions. The advice is to review your pet's medical history with your veterinarian before choosing one, especially if your dog has had seizures. The newest one is a shot. In July 2025 the FDA [approved Bravecto Quantum](https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-first-long-acting-flea-and-tick-treatment-dogs), an injectable for dogs 6 months and older that protects for 8 to 12 months, and said it "must only be prescribed by a licensed veterinarian." We give these drugs no product cards: choosing one is a conversation with your vet. ## How to apply any of them safely The EPA's [safety tips](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) apply to every product here: - Use it only on the species and weight the label names, and only the amount for that weight. A product for a bigger animal "may overexpose your pet to the pesticide." - Do not use it on kittens or puppies unless the label allows it; the label gives the minimum age or size. - Follow label limits on weak, aged, medicated, sick, pregnant or nursing pets. - Watch your pet after the first application, and keep the box: it has the directions and the registration number you need for a report. If your pet reacts, the EPA's [adverse reaction page](https://www.epa.gov/pets/what-do-if-your-pet-has-adverse-reaction-flea-and-tick-product) lists signs such as skin irritation or redness, vomiting or diarrhea, and trembling, a depressed appearance or seizures. It says to bathe the pet with mild soap and rinse with large amounts of water, remove a collar immediately, and call your veterinarian or the National Pesticide Information Center at 1-800-858-7378. ## How long to keep it up The Companion Animal Parasite Council recommends that "all dogs should be treated year-round and throughout their life with flea control products," and says the same for cats, in its [flea guidelines](https://capcvet.org/guidelines/fleas/). It adds that once an infestation is established it may take several months to control, and "every pet in the home must be treated." For ticks, CAPC's [tick guidelines](https://capcvet.org/guidelines/ticks/) (updated March 30, 2023) say "all dogs should be treated year round," because tick activity varies by year, season and region and the brown dog tick can infest homes in any month. It also advises frequent tick checks when visiting tick-infested areas. Whether your pet needs a pesticide spot-on, a collar or a prescription chew depends on its health, age, where you live and who else is in the house. Ask your vet which fits your pet ([more on that](https://petprooflab.com/about#veterinary)). ## Recalls None of these five products or brands appears on our [pet product recall page](https://petprooflab.com/recalls), which tracks FDA and CPSC pet recalls, as of September 28, 2026. The Seresto review above was a registration decision, not a recall. For the rest of a grooming routine, see our guides to [deshedding brushes](https://petprooflab.com/grooming-health/best-deshedding-brushes) and [dog shampoo](https://petprooflab.com/grooming-health/dog-shampoo); a weekly brushing is also a good time to look for fleas and flea dirt. ## Frequently Asked Questions ### Can I use a dog flea treatment on my cat? No. The EPA says never to apply dog products to cats, and permethrin in dog spot-ons such as K9 Advantix II can cause severe tremors and seizures in cats. K9 Advantix II's label says it may be fatal to cats. ### How do I tell if a flea product is EPA-registered or FDA-approved? Look for "EPA Reg. No." on the label; that means an EPA-registered pesticide. FDA-approved drugs, like the isoxazoline chews, carry FDA approval instead and are chosen with your veterinarian. ### Are Seresto collars safe? The EPA kept Seresto registered in 2023 after reviewing incident reports, but required new warnings and limited its approval to five years. It found the deaths it could link to the collar involved strangulation or trauma, often with a release mechanism that failed. ### Do dogs need flea and tick prevention in winter? The Companion Animal Parasite Council recommends year-round flea and tick control for dogs and cats, because the brown dog tick can infest homes in any month and flea infestations take months to clear. ### What should I do if my pet reacts to a flea treatment? Bathe your pet with mild soap and plenty of water, take off any collar, and call your veterinarian or the National Pesticide Information Center at 1-800-858-7378, per the EPA. --- *PetProofLab is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. We did not test these products; registration numbers and ingredients are from EPA-stamped labels, and features from the listings. This guide is for general information and is not veterinary advice.* ## Sources - U.S. Environmental Protection Agency: [Frontline Plus for Dogs](https://www3.epa.gov/pesticides/chem_search/ppls/065331-00005-20110728.pdf) - U.S. Environmental Protection Agency: [Frontline Plus for Cats](https://www3.epa.gov/pesticides/chem_search/ppls/065331-00004-20110726.pdf) - U.S. Environmental Protection Agency: [Advantage II Small Cat](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00151-20170627.pdf) - U.S. Environmental Protection Agency: [K9 Advantix II Large Dog](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00143-20220214.pdf) - U.S. Environmental Protection Agency: [Seresto](https://www3.epa.gov/pesticides/chem_search/ppls/011556-00155-20230713.pdf) - U.S. Environmental Protection Agency: [Epas regulation flea and tick products](https://www.epa.gov/pets/epas-regulation-flea-and-tick-products) - U.S. Food and Drug Administration: [Fact sheet pet owners and veterinarians about potential adverse events associated isoxazoline flea](https://www.fda.gov/animal-veterinary/animal-health-literacy/fact-sheet-pet-owners-and-veterinarians-about-potential-adverse-events-associated-isoxazoline-flea) - U.S. Environmental Protection Agency: [Controlling fleas and ticks your pet](https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet) - ASPCA: [Not all pets are same why species matters pet toxins](https://www.aspca.org/news/not-all-pets-are-same-why-species-matters-pet-toxins) - ASPCA: [ASPCA alert](https://www.aspca.org/news/feline-toxins-steer-clear-kitten-season) - yourpetandyou.elanco.com: [K9 Advantix II page](https://yourpetandyou.elanco.com/us/our-products/k9-advantix-ii) - U.S. Environmental Protection Agency: [Epa evaluation pet spot products analysis and plans reducing harmful effects](https://www.epa.gov/pets/epa-evaluation-pet-spot-products-analysis-and-plans-reducing-harmful-effects) - U.S. Environmental Protection Agency: [Avoid counterfeit pesticide products dogs and cats](https://www.epa.gov/pets/avoid-counterfeit-pesticide-products-dogs-and-cats) - U.S. Environmental Protection Agency: [Seresto review](https://www.epa.gov/pets/seresto-pet-collar-review) - U.S. Environmental Protection Agency: [2023 announcement](https://www.epa.gov/pesticides/epa-requires-additional-mitigation-measures-seresto-pet-collars) - U.S. Food and Drug Administration: [Fda approves first long acting flea and tick treatment dogs](https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-first-long-acting-flea-and-tick-treatment-dogs) - U.S. Environmental Protection Agency: [Adverse reaction page](https://www.epa.gov/pets/what-do-if-your-pet-has-adverse-reaction-flea-and-tick-product) - capcvet.org: [FLEAS page](https://capcvet.org/guidelines/fleas) - capcvet.org: [TICKS page](https://capcvet.org/guidelines/ticks) --- Last updated: 2026-09-28 Canonical URL: https://petprooflab.com/grooming-health/flea-and-tick-prevention How to cite: "Flea and Tick Prevention (2026): EPA vs FDA Products, and the Dog Products That Can Kill Cats", PetProofLab, https://petprooflab.com/grooming-health/flea-and-tick-prevention (checked 2026-09-28). Disclosure: as an Amazon Associate PetProofLab earns from qualifying purchases. Safety information summarizes public guidance and is not medical advice.