The Best Flea Treatment for Dogs
The best flea treatment for dogs should be effective, convenient, and safe enough to use around kids and other pets. To find our top picks, we consulted three vets and an entomologist, researched active ingredients, then examined the top spot-on and oral meds ourselves. In the end, the right choice for you is a matter of your dog's needs and personal convenience.
Frontline Plus is a spot-on medicine. Its insecticide kills fleas, ticks, and lice while its insect growth regulator prevents new flea larvae from developing for up to a month. And its snap-off applicator was hands down the easiest to use.
Bayer Advantus Soft Chews kills 96% fleas within an hour and comes in a flavored chew that looks like a dog treat. Use once per day until your home is flea-free.
The Best Flea Treatment for Dogs
To kill and prevent both fleas and ticks for up to a month, you’ll want to use a spot-on medicine. Frontline Plus uses fipronil to kill fleas, ticks, and lice, plus (s)-methoprene to keep fleas from growing and reproducing. Like all spot-on treatments, the medicine is applied to a small area on the back of your dog’s neck, so they can’t lick it off. Since it’s easy to accidentally come into contact with the medication, it’s best to monitor your pet and limit their contact with people and other animals for 24 hours.
PetArmor Plus and Sentry Fiproguard Plus use the same active ingredients to kill all stages of fleas and ticks but costs about half as much. However, their applicators aren’t as well-designed as Frontline Plus. When we opened the applicator, some of the medication leaked out — not ideal when handling insecticides. Frontline’s snap-off applicator kept more of the product intact until we were ready to apply.
If you just need to treat your dog fast, consider an oral medication. We liked Bayer Advantus Soft Chews, a chewable treatment that looks and smells like a dog treat. It starts killing fleas in under an hour, and you don’t have to worry about contact with other pets or children after application. The downside is that it only kills adult fleas — it won’t prevent against future generations, so you’ll need use it daily until your home is flea-free or switch to a spot-on after the first day.
Sentry Capguard, PetArmor FastCaps, and Capstar Tablets work just as quickly, but come in a pea-sized tablet you mix into your dog’s food. They all look identical, but Sentry Capguard tends to be the cheapest.
How We Found the Best Flea Treatment for Dogs
We started with 68 medications — collars, chewables, shampoos, sprays, and spot-ons — to choose from. These were the most common over-the-counter flea treatments for dogs available online and in stores, including 1800PetMeds, Petco, Drs. Foster & Smith, and PetSmart.
From there, we talked to pet and insect experts, and researched ingredients to find which medication works best — and is safe enough to use in homes with kids and other pets.
Our goal was to find effective, easy-to-use treatments.
All flea medications fatally attack fleas’ nervous systems, but there are lots of different types to choose from:
- Spot-ons are a small, concentrated liquid applied to the back of a dog’s neck. Within 24 hours, the medication dissipates into the natural oils on the dog’s skin, killing fleas and preventing new generations from developing for up to a month.
- Oral chews and tablets use insecticides that transfer to the dog’s bloodstream in under an hour. When a flea bites the dog, it’s exposed to the insecticide and dies. While chews and tablets work faster than any other product, they only last 24 hours — over-the-counter oral medications are only intended to treat an existing flea problem. They won’t protect your dog from a future infestation.
- Collars contain insecticides that either repel fleas or absorb into dogs’ fat layer to kill fleas. The collars we found last anywhere from six to twelve weeks.
- Shampoos kill adult fleas quickly, but typically only last 24 hours, like oral tablets and chews. The medication is potent and is usually only necessary for animals with a severe infestation.
- Sprays linger in the oils on a dog’s skin. They work similar to spot-ons, but are more diluted and require you to apply the medication all over your dog’s body as often as once a week.
With so many options to choose from, we focused our attention to spot-ons, tablets, chews, and collars. We figured most dogs and owners would prefer these options. They’re all quick and painless; it only takes a minute to administer a concentrated dose. Sprays and shampoos are the exact opposite – they’re messy and have to be applied all over your already stressed-out dog. That left us with 40 flea-killing products to keep researching.
We cut any ingredients with scary side effects.
An effective flea treatment needs to use a pesticide — a chemical that kills bugs. All pesticides used in flea medication are approved by the Environmental Protection Agency, but they can still cause serious harm to humans and other pets if they’re handled incorrectly. That’s why it’s so important to avoid touching any topical medication directly and always wash your hands after applying it.
Weight and dosage matter. Different-sized dogs require different doses of medicine. Always check the label to make sure the product you're using is intended for your pet's weight range.
Pyrethroids: The Agency for Toxic Substances & Disease Registration, a subsection of the CDC, says that humans exposed to pyrethroids can experience numbness, itching, burning, stinging, or tingling. On the label, pyrethroids are any ingredient that ends in “-thin” (permethrin, deltamethrin, flumethrin, etc,) and etofenprox.
If you have a cat, avoid medication with pyrethrin, a natural insecticide derived from chrysanthemum flowers. It’s safe for dogs and humans, but it can trigger seizures in cats. Our top picks happen to be pyrethrin-free, though many shampoos, sprays, and powders are not. If you have a cat that cuddles or grooms your dog, double check your ingredient labels.
We were surprised to learned that all of 12 of our flea collars used one of these ingredients. While many dogs may not experience side effects, there are plenty of safer spot-on and oral treatments out there. When it comes to the health and safety of our pets, we wanted to play it safe.
We wanted a spot-on that could also kill ticks.
All of our remaining spot-on and oral treatments kill adult fleas, but we found a handful of spot-ons medications with insecticides that also target ticks.
According to the 2016 Banfield Pet Hospital State of Pet Health Report, ticks are found in most areas of the United States. Tick-borne diseases, like Lyme disease and Rocky Mountain spotted fever, can be life-threatening. They’re much easier to prevent than treat, so it’s best to have a medication that can kill both fleas and ticks.
And prevent new fleas from growing.
All the flea treatments on our list use insecticides to kill adult fleas. But Mike Potter, an entomologist at the University of Kentucky, says that the best way to get rid of fleas in your home is to use a combination of insecticides and insect-growth regulators (IGRs). Ralph Williams, PhD, a veterinarian and public health entomologist, agreed and explained:
“IGRs are chemicals that mimic natural insect hormones to prevent them from laying eggs.”
We wanted a spot-on treatment that could eradicate a flea problem from the ground up, so we made sure our top spot-ons used an IGR-insecticide combo. IGRs appear on spot-on medication labels as (s)-methoprene or pyriproxyfen. In fact, that’s where the “plus” in Frontline Plus comes from.
That left us with 13 flea medicines.
After narrowing down our list, we looked through scientific studies to compare efficacy of ingredients. As it turns out, they all live up to their label claims. Our top picks are the easiest to find and apply.
Our Picks for the Best Flea Treatment for Dogs
Best Monthly Flea and Tick Treatment
Frontline Plus Flea & Tick Treatment This popular medication lives up to the hype — one monthly treatment combats the entire flea lifecycle, plus ticks and lice. It also comes in an easy-to-squeeze applicator.
All three use the same active ingredients: fipronil to kill bugs and (s)-methoprene to interrupt their growth cycle. One monthly application kills all stages of fleas, including eggs, larvae, pupae, and adults. They also combat multiple types of ticks and chewing lice.
You can even use these spot-on treatments on puppies as young as 8 weeks, or on breeding, pregnant, or lactating dogs. These dogs are just as susceptible to fleas and ticks – but puppies can’t always handle the insecticides used in other topical medications. Just make sure you’re using the right product for your pet’s size. Each spot-on manufactures different-sized doses for small (under 22 lbs.), medium (23–44 lbs.), and large (48–88 lbs.) dogs.
According to the label, Frontline starts killing fleas within four hours after application and kills 100% of fleas within 12 hours. PetArmor and Sentry claim to take 12 hours to begin killing fleas. They use the same active ingredients, so we’re not sure why they make different claims about how quickly the product will work. Regardless, studies have shown that a combination of fipronil and (s)-methoprene can kill 100 percent of fleas within seven days. While it’s not as fast-acting as the oral medicine we found, the insect growth regulator will eliminate a flea infestation much faster and much easier than a chew or tablet.
These products kill fleas the same way, but we uncovered a few noticeable differences during our hands-on testing. Specifically, we found that Frontline Plus uses a superior applicator. To open, you peel off the protective seal then snap off the long, narrow tip. That might sound like a minor detail, but compare that to PetArmor and Sentry’s applicators. We had to cut them open, and the medicine leaked out onto our scissors each time. You’ll have to take extra caution to make sure it doesn’t leave a chemical residue on you or anything you touch.
To apply Frontline, (left) you remove the applicator from the foil package, snap off the end of one of the applicators, and apply it on the back of your dog’s neck. Many spot-on treatments, like PetArmor Plus (center) and Sentry Fiproguard Plus (right), use similar application techniques.
We noticed a range of scents as well. Most spot-ons (Frontline Plus included) have a distinct chemical scent. That’s to be expected – these are chemicals after all – but Sentry and PetArmor were slightly more mild, even faintly citrus. But really, the difference is tiny, and the scent from any medicine will likely fade after a day or so.
Price-wise, Frontline Plus is on the higher side of average at around $10 per monthly treatment for the smallest-sized dose. PetArmor Plus is less than half that at $3 per treatment. Sentry Fiprogruard Plus sits in the middle at about $5 per treatment.
Fast-Acting Flea Relief
To give your dog relief from fleas as quickly as possible, use an oral medication. These medications work through your dog’s bloodstream to start killing fleas in under an hour, but they won’t protect against a future infestation or any other type of pest. You’ll give your dog a dose up to once per day until the infestation is under control, but if you have a persistent flea problem at home, or your dog is regularly exposed to ticks, follow up with a spot-on treatment after a few days. Never combine flea medicines at the same time without talking to your vet first.
Our favorite oral treatment is Bayer. Unlike most flea medications, your dog might actually want to eat it. These flavored chews look and smell like a regular dog treat, but contain imidacloprid — an insecticide acts through the dog’s bloodstream. When a flea bites the dog, it’s exposed to the insecticide and dies.
According to the label, Bayer kills 96 percent of fleas within an hour. Note that there are two different versions of the product – one for dogs under 25 pounds and one for dogs over 25 pounds.
PetArmor FastCaps, Sentry CapGuard, and Capstar Tablets work the same way, but come in a tablet instead of a chew. They all look identical — a small, white tablet no bigger than a pea, but you’ll probably still need to hide it in your dog’s food.
They each use nitenpyram, an insecticide that starts to kill fleas even faster – just 30 minutes. Your dog can take up to one pill per day, though one study found that the effects can last up to 48 hours. They’re are safe for cats and kittens too — just make sure you’re using the right dose for your pets’ weight.
PetArmor Fastcaps, Sentry Capguard, and Capstar tablets are all identical. Bayer Advantus Soft Chews resemble an everyday dog treat.
Did You Know?
There are lots of ingredients, but they all do one of three things.
|Ingredients||What They Do||Found In|
|Cyphenothrin, fipronil, imidacloprid, nitenpyram, spinosad||Kill fleas by targeting their nervous system||Frontline, PetArmor, Sentry, Parastar, Flea5X, Certifect, PetAction, PetLock|
|(S)-methoprene, pyriproxyfen||Mimics flea hormones to prevent fleas from laying eggs and to keep eggs, larvae, and pupae from developing into adult fleas||Adams, Bio Spot, Bayer, Frontline, PetArmor, Sentry, Flea5X, Certifect, PetAction, PetLock, Zodiac, Advecta, PetArmor, Vectra, K9 Advantix|
|N-octyl bicycloheptene dicarboximide (MGK 264)||Speeds up the work of insecticides||Sentry, Bayer, Bio Spot, Adams, Espree, Bio-Derm, Perfect Coat, PetLock|
Southern states have the highest risk of flea infestation.
According to the Banfield Pet Hospital State of Pet Health 2016 Report, Louisiana, Alabama, and Florida were among the top five states with the greatest prevalence of fleas in cats and dogs. This is because fleas do best in warm, wet, and humid climates.
Fleas live in areas frequented by animals and humans and seek out dark, warm, humid places — usually carpets, bedding, under furniture, or in garden debris. Basic yard maintenance and vacuuming are the easiest ways to prevent an infestation.
We recommend talking to your vet.
We only looked at over-the-counter flea medicine, but there are more options available with a prescription. Dr. Ari Zabell at Banfield Pet Hospital, explained “Some of the current OTC medications are simply medications that were previously available only by prescription, but have since proven safe enough to be available over the counter.” Manufacturers make their products prescription-only to ensure that you talk to your vet beforehand. But that doesn’t mean prescription medicine isn’t safe. When your vet recommends a flea medication, they can account for your dog’s medical history and lifestyle.