Fleas aren't only about itching. Biting fleas can cause disorders in dogs: flea allergy dermatitis, secondary skin infections, tapeworms, and even anemia. Once your dog becomes infested with these parasites, it's can difficult to get rid of them all. Good flea pills for dogs will not only kill parasites, but also prevent re-infestation later on.

Because dog flea pills contain strong chemical ingredients, it's imperative to talk with your veterinarian before giving your pet any kind of medication, including flea preventatives. Oral flea and tick preventatives for dogs are gaining popularity with vets and pet owners, but they aren't safe (PDF) for every dog.

Similar to topical flea treatments for dogs, flea pills usually only need to be administered once per month. But unlike topical treatments, dog flea pills are more convenient for dog owners. Below we'll talk about the effectiveness and safety of dog flea pills, how they work and how to use them, review the best flea pills for dogs we liked in the past.

Types, Safety and Efficacy of Dog Flea Pills

Oral flea medications for dogs is the most convenient way to prevent parasites on your pet, but because they are administered orally, many pet owners have concerns over their safety. Fortunately, there's been a lot of research in testing how a flea pill for dogs works, and the safest way to administer these parasite preventatives.

In the US and Europe, there are several popular and well-studied brands and types of prescription and over the counter dog flea pill types that pet owners have to choose from. Most of these will be prescribed by a veterinarian.

Some other flea pill for dogs products are available over the counter and are designed to do the same job – kill fleas, ticks and other common dog parasites. However, there will be a lot less research available for the OTC dog flea pill products.

So what's the difference between vet prescribed and over-the-counter flea pills?

The difference are active ingredients. Over-the-counter products may use more of natural ingredients, and be less harmful and less toxic. At the same time, they may also be less effective than scientifically proven strong chemicals like those above.

Out of the five above mentioned, the one that stands out is Capstar (nitenpyram). This brand is usually cheaper and works as a short-term quick solution to rid dogs of fleas. It was shown to effectively kills fleas for at least up to 24 hours. The other ones are all long-term solutions, administered to a dog orally once a month.

You will also notice that every brand of vet prescribed flea pills has a different active ingredient. All of them are generic names for insect growth inhibitors and regulators, and insecticides to control the flea population. Ultimately, they all do the same job. What you have to be careful about is whether a specific insecticide is fine to be used with your dog.

Which Flea Pills for Dogs Are Most Effective?

There's been a number of studies testing the efficacy of these dog flea pill products and comparing them among each other. The more popular brands have more research behind them but it's also important to note that many of these studies were funded by the companies themselves.

In a well-known 2014 study, Bravecto (fluralaner) was compared to topical treatment Frontline (fipronil) and the researchers concluded much higher efficacy of Bravecto over Frontline (Rohdich et al. 2014). Both dog flea pills were shown to be safe for canines.

In a 2014 study with cats, Comfortis (spinosad) was shown to be an effective treatment against fleas and safe for pets to use (Franc et al. 2014). Then, a blinded, randomized, controlled study with dogs compared spinosad active ingredient with the effectiveness of Bravecto (fluralaner) and found the latter to be 3 times more effective than spinosad flea treatment (Meadows et al. 2014).

A much older, independent study with dogs and cats tested the effectiveness of a few general dog flea pill products' active ingredients, and found that oral flea medication reduces the number of fleas by 97.3% within the first 7 days. Overall, all products showed the results of 89.5% flea reduction by day 28 and 100% flea reducation by days 80-90, on average (Dryden et al. 2001).

There is a lot more research available on the efficacy and safety of these top rated flea pills for dogs, and the consensus is that they're generally safe and extremely effective. However, side effects – while rare – may occur. Most common adverse effects are lack of appetite, vomiting, diarrhea, lethargy, itching, difficulty breathing, or reddened skin.

The same cannot be said about ticks, however.

Majority of these studies prioritized fleas. Some have also found the products to be effective against ticks, too; however, the evidence isn't as strong. Furthermore, another study from 2016 with dogs tested several products (Pfister et al. 2016). They worked well for fleas, but tick re-infestation occurred just 7 days after the treatment.

dog tick infestation after treatment
Tick infestation 7 days after treatment. Credit: Dr M. Canfield / Pfister, 2016

Tick infestation is much harder to deal with when the case is severe. Consultation with a vet and a proper plan for treatment using prescription pills will be required in some cases.

How Do Recommended Flea Pills for Dogs Work?

Keep in mind that anti-flea pills for dogs work as a preventative solution against these parasites. When given according to the instructions, these pills prevent new flea eggs from hatching on your dog. According to Dr. Michael F. Potter, an Extension Entomologist at the University of Kentucky College of Agriculture:

“When an adult female flea bites a Program-treated dog or cat, the flea ingests the active ingredient (lufenuron) which then passes into her eggs and prevents them from hatching.” – Dr. Michael F. Potter, DVM (source)

Fleas and other parasites that attack dogs are also dangerous to humans and can have a negative impact (PDF) on our health too. Not only are humans extremely sensitive to these bites (so you'll be extremely itchy), fleas also can transmit bacteria and viruses through their saliva.

“What if my dog already has fleas?”

If your dog is already infested with fleas, see this video guide on how to remove fleas from a dog. Samantha has covered everything from preventing fleas to removing them from the dog and within the house, including the best solutions (store bought and homemade).

Ultimately, prevention is the best way to fight off fleas on dogs. So once you remove them, ensure that your pooch is protected for the future.

Many preventative measures (such as electric flea traps, flea collars, flea shampoos, flea powders, flea drops and topical flea treatments) only ward off fleas and ticks. The best flea pills for dogs will also keep your pet safe from other parasites including heartworms and intestinal parasites.

As the old saying goes, an ounce of prevention is worth a pound of cure. Don't wait until your dog is infested with fleas to take action. Research, find and purchase best flea pill for dogs products now, discuss it with your veterinarian, and prevent the flea infestation from taking place on your pet.

Top 6 Best Flea Pills for Dogs

1Capstar Flea Tablets for Dogs and Cats
by Capstar

Capstar Flea Tablets are FDA-approved for the treatment and control of fleas in dogs weighing 2 to 25 pounds. The active ingredient in Capstar is nitenpyram, which exterminates adult fleas 30 minutes after treatment and attains peak level within 4 hours, according to most recent studies.

Capstar Fast-Acting Oral Flea Treatment for Dogs
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Capstar Fast-Acting Oral Flea Treatment for Dogs
  • One oral tablet starts killing...
  • Tackle flea infestations fast...
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  • Includes 6 doses for use with...

It will not effectively kill flea eggs as fast as it kills fleas, so you may need to use other formulations for the eggs, or repeat treatment until all eggs have been hatched and destroyed. You may safely administer a single dose each day until your dog is completely flea-free. This item comes in a pack of 6 tablets.

Capstar Flea Tablets for Dogs is a good (stronger) alternative if you’re not seeing results from using your dog’s flea shampoo or spray, or if bathing your dog frequently is not feasible. You have to take note, however, that Capstar dog flea pill is not long-acting. Its efficacy lasts only up to 24 hours after which you may safely give your pet another pill. Capstar can only affect adult fleas that are on your dog during this period.

If you think that giving your pet these top rated dog flea pills every day is an easy way out of flea infestation, unfortunately, you cannot (and will need to use a different product). When your pooch is treated with Capstar, you also have to deep-clean your house and surroundings and destroy all possible flea habitats to prevent re-infestation.


  • FDA approved
  • The active ingredient in these recommended flea pills for dogs is nitenpyram (scientifically proven to be effective)
  • Exterminates adult fleas 30 minutes after treatment and attains peak level within 4 hours

  • Only suitable for dogs weighing less than 25 pounds
  • Must be given daily until all fleas are gone
  • Can make some dogs sick


2Maximum Flea Defense QuickTabs Nitenpyram
by Dog MD

Like Capstar, Dog MD’s QuickTabs pills contain nitenpyram as its active ingredient and starts working 30 minutes after your dog has been treated with it. You may not notice decrease in scratching right away, but as more and more fleas die off, you’ll see your pooch scratching less and less within the next 24 hours.

This flea treatment is FDA-approved and doesn’t interfere with other medications. It provides quick-relief from itchy fleabites and is recommended for pets weighing 2-25 pounds. It can be safely given once daily or until you notice that there are no more fleas on your pet.

Dog MD's best flea pills for dogs are quick-acting, but their efficacy is short-term, same as Capstar. That means that if after 24 hours, fleas from the carpet or other flea hangouts found their way to your dog, the pill would have little effect to them, if at all. Your pet has to take another pill. It would be best to match the potency of Dog & Cat MD Maximum Defense Quick Tabs Flea Treatment with efforts from your part to eliminate fleas that could get access to your pet.

QuickTabs dog flea pill does not affect flea eggs, too. Giving your pets a pill daily would ensure that once eggs hatched and became adults, the QuickTabs would get to them and eliminate them for good. If you’re planning to hunt with your dog or travel to a place known to be a flea hotspot, it would be a good idea to give your pet a pill before coming home because your dog could easily pick up fleas between here and there. With QuickTabs, the fleas sure won’t last a day or have a chance to populate.


  • The active ingredient in these flea dog pills is nitenpyram (scientifically proven to be effective)
  • Starts working 30 minutes after ingestion
  • FDA approved
  • Doesn’t interfere with other medications

  • Only suitable for dogs weighing less than 25 pounds
  • Must be given daily until all fleas are gone, as they do not kill flea eggs
  • Can make some dogs sick


3PetArmor FastCaps for Dogs

PetArmor’s FastCaps pills also contain the FDA-approved and fast-acting ingredient nitenpyram which destroys adult fleas that cause flea allergy dermatitis. You may place it directly into your pet’s mouth or mix it with food.

PetArmor FastCaps (nitenpyram) Oral Flea Control...
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PetArmor FastCaps (nitenpyram) Oral Flea Control...
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  • No odor or messy application

You’ll see results in about 30 minutes. FastCaps can be bought over the counter so you need not get a vet’s prescription for it. It’s safe for dogs weighing at least 2 pounds and even for pregnant and lactating pets.

PetArmor's popular flea pills for dogs are safe and can be used in conjunction with other topical flea meds, antibiotics, and deworming pills (but must be discussed with a vet). PetArmor FastCaps for Dogs are better than topical treatments because it can’t be rubbed or washed off. Initially, you may notice your pet scratching. This reaction is normal and temporary. It only means that the fleas are dying.

It’s important to keep in mind that FastCaps’ dog flea pill intended use is to break the flea’s life cycle. It kills the adult fleas on your dogs at the time of the treatment. Without adults, flea reproduction would not be possible. However, you’d need another remedy to eliminate the eggs present at the time of the treatment and wipe out fleas that are still thriving in their secret places within your home or off the lawn.


  • The active ingredient is nitenpyram (scientifically proven to be effective)
  • FDA approved
  • Starts working 30 minutes after ingestion
  • Safe for dogs weighing at least 2 pounds and pregnant and lactating pets
  • Available over-the-counter

  • Only kills adult fleas
  • Doesn't work for all dogs


4Sentry Capguard (nitenpyram) Oral Flea Tablets
by Sentry Pet Care

Sentry Capguard Tablets has the same active ingredient as Capstar and the three other mentioned best flea pills for dogs we’ve named so far. Capguard interrupts flea infestation by killing adult fleas on your pet’s body.

SENTRY Capguard (nitenpyram) Oral Flea Control...
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SENTRY Capguard (nitenpyram) Oral Flea Control...
  • Treat Flea Infestations With...
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  • NADA 141-175 Approved by FDA

Pets must weigh at least 2 pounds and be at least 4 weeks old to be safely given this flea treatment. This pill works within minutes from the moment your pet swallows it and continues working in the next 24 hours. Administering the pill is no hassle and leaves no mess as long as your pet is not averse to taking it.

One dose of Senty's dog flea pill kills a lot of fleas, and they start falling off in less than an hour. As in the other nitenpyram brands, you’d need a separate medication for flea eggs and possibly anti-flea sprays for fleas that are in hiding. Sentry Capguard (nitenpyram) Oral Flea Tablets would be great to use in conjunction with treatments that affect flea eggs and larvae. Since Capguard works quickly at eliminating the adult population, it hastens the work of the other treatment.

The downside of using this product alone would be the length of time that it has to be used to completely eliminate the fleas. That is so because the eggs have to be hatched and become adults first before Capguard can affect them. If you only have one pet, that may not be so difficult or expensive. With several pets, however, the cost will necessarily increase by their number, and treatment may even run to several weeks.


  • The active ingredient is nitenpyram (scientifically proven to be effective)
  • FDA approved
  • Starts working 30 minutes after ingestion
  • Works on dogs weighing more than two pounds who are more than 4 weeks old

  • Only works on adult fleas
  • It takes longer to eliminate the infestation than other products
  • Can make some dogs ill


5Flea Away: The Natural Flea Repellent for Dogs
by Flea Away

Here's something a little different. Flea Away is actually a dietary supplement that contains brewer’s yeast, liver powder, collagen powder, and water-soluble vitamins and minerals. These chewable pills have a unique way of shooing away fleas in a natural, less toxic to dogs way.

Flea Away All Natural Flea, Tick, Mosquito...
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Flea Away All Natural Flea, Tick, Mosquito...
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Unlike nitenpyram-based medications, the fleas need not bite your pet first before they are affected by the treatment. Instead Flea Away repels fleas by the odor that your pets give off as a result of taking these pills regularly. These liver-flavored pills support regular meals and are great as training rewards or treats.

Flea Away Natural Flea Repellent for Dogs will not only repel fleas, it will also discourage ticks and mosquitoes from living off your pet. This will not happen overnight; in fact, you’d have to give these pills to your dog for about a month before you’d see results. Remember that Flea Away dog flea pill does not harm fleas. Instead, it works by making your pet as unappealing to fleas as possible, and that takes time.

This is a great alternative to insecticides or chemical-based flea treatments because it’s safe both to pets and humans. The tablet is a bit too large, and while most dogs have no problem with the size, smaller or pickier pets may. If your pet is something like that, you may have to crush the tablet and mix it with food. On the downside, it simply isn't as effective as above brands – it may work on some dogs, and not on others.


  • No need for the fleas to bite your dog like with other pills, as these dog flea pills repel fleas before they bite
  • Repels fleas, ticks and mosquitoes
  • Made with natural ingredients
  • Made and sourced in the USA

  • We were disappointed in the size of these tablets, as they are way too big to give to our small dogs without having to break them apart
  • Our dogs seemed put off by the smell of these tablets and would not eat them
  • Doesn't always work


6Four Paws Brewers Yeast Dog Flea Tablets
by Four Paws

Similar to the above, Four Paws’ Brewers Yeast Tablets are a daily food supplement formulated to promote the overall health and wellness of your pets and protect them against flea and tick infestation. It is made in the USA and uses natural and nutrient-rich ingredients like brewer’s dried yeast and garlic powder. It contains protein, biotin, and zinc to keep pets’ skin and coat healthy. There are five sizes available starting from 125-count to 2000-count.

Four Paws Brewers Yeast Garlic Flavored Dog and...
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Four Paws Brewers Yeast Garlic Flavored Dog and...
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The advantage in Four Paws Brewers Yeast Garlic Flavored Dog and Cat Tablets is clearly in its wholesomeness, there being no harmful chemicals in its ingredients list. It is highly nutritious and helps keep skin and coat healthy. This dog flea pill controls shedding and, to some degree, prevents flea and tick infestation. Giving them to your pets is also very easy because the pills look so much like treats.

Even if it's a natural choice, they’re not the best choice for treating a flea infestation in your pets though, in the same manner that our first four products were. In other words, you would not always find fallen fleas on the floor after giving your pets Four Paws’ Brewers Yeast – sometimes it works, most times it doesn't. However, if you’re thinking of a product to use in the long-term to prevent flea infestation in your pet and don't wish to use above brands, then this would be a decent and safer choice.


  • Natural daily suppplement
  • Made in the USA
  • Includes natural proteins, zinc, and biotin for a healthy skin and coat

  • Must give 1 tablet per day for every 10 pounds of body weight
  • Our dogs seemed put off by the smell of these tablets and would not eat them
  • Doesn't always work

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