Are oral flea treatments safe for dogs?

Any flea treatment or preventative that has been approved by the FDA is safe and effective for the majority of dogs, said veterinarian Joanna Woodnutt of SeniorTailWaggers.com. But there are always exceptions. “For instance, many oral flea and tick preventatives contain a class of drugs called isoxazolines. Whilst they don’t cause seizures, these drugs may reduce the seizure threshold in some dogs, so if your dog is already prone to seizures this medication isn’t suitable for them,” Woodnutt told The Spruce Pets. This class of drugs is generally not recommended for dogs with neurologic disorders, or breeds with the MDR-1 gene mutation, such as Australian shepherds. “The safety of a drug choice is one of the reasons that it’s a good idea to talk to your veterinarian about flea and tick treatment—they are best placed to help you assess the risks to your dog and come up with the best, safest, and most effective option.”

What is the best flea and tick treatment pill?

There are many prescription oral pills that treat and prevent flea and ticks on your dog, but the best treatment depends on your individual dog. Modern pills from the isoxazoline class (including Bravecto, Credelio, Nexgard, and Simparica) are “very reliable flea and tick treatments,” said Woodnutt. “Which one you choose depends on the length of coverage you need (for example, Capstar is quick acting but only lasts 24 hours, so it needs following up with additional solutions), which weight range suits your pet, whether your pet is still growing, and whether your pet has underlying conditions or other medications that need to be considered,” Woodnutt said. Some, like the monthly chewable Simparica Trio, are also combined with dewormers. “The choice of the right treatment therefore also depends whether your dog would benefit from the combination treatment, or whether this would be doubling up on medications like heartworm preventative or dewormer,” Woodnutt told The Spruce Pets. “These are all things your vet will consider when helping you choose a good flea treatment protocol.”

Are cat flea and tick treatments safe for dogs?

According to Woodnutt, it’s never a good idea to use a medication targeted for one species on another. “Differences in the drugs used and the concentrations in the medication mean that using cat treatments on the dog is not safe,” she said. “At best, they may be ineffective, causing a flea infestation or allowing a tick to spread disease to your dog. At worst, they can be dangerous, as cats and dogs are allergic to different drugs.”

The 4 Best Flea and Tick Treatments for Dogs

Fleas can lead to conditions like hair loss, allergic dermatitis, and tapeworms, while ticks can cause skin infections and illnesses such as Lyme disease. These pests can not only irritate your pet and lead to more serious problems, they can also invade your home.

Prescription oral insecticides are popular because they kill the pests currently on a pet and work as a preventative, stopping new flea and tick infestation. These are most often prescription formulas that you order through your vet or online with your vet’s prescription.

But there are many other options for treatment, including collars, sprays, shampoos, and topical formulas you squirt on your pet’s back. We researched a variety of options, including flea and tick treatments specific to older dogs, puppies, and different sizes of dog. While our picks were made in consultation with veterinarians, it's important to consult your own veterinary professionals to find a flea treatment that's best for your dog's needs.

Here are the best non-prescription flea and trick treatments for dogs.

Our Top Picks

Best Topical:

Frontline Plus Flea & Tick Large Breed Dog Treatment at Amazon

Jump to Review

Best for Puppies:

Capstar Fast-Acting Oral Flea Treatment for Dogs at Amazon

Jump to Review

Best Spray:

Frontline Spray at Chewy

Jump to Review

Best Shampoo:

Adams Plus Flea & Tick Shampoo at Amazon

Jump to Review

In This Article

Our Picks
What to Look for in Flea and Tick Treatments for Dogs
FAQ
Why Trust The Spruce Pets

4.6

Frontline Plus Flea & Tick Large Breed Dog Treatment

Amazon

View On Amazon View On Chewy View On Walmart

What We Like

Kills fleas, eggs, and larvae, as well as lice and ticks
Lasts 30 days
Waterproof

What We Don't Like

Some dogs irritated by chemicals at application site
May not be enough to prevent infestations in areas with large flea populations

Apply this topical treatment between your pet’s shoulder blades once a month to fight adult fleas, flea eggs, flea larvae, chewing lice, and ticks. Protection lasts for about 30 days and is waterproof if your dog takes a bath or goes swimming.

To apply, part your dog’s fur between the shoulders and squeeze out the contents of the entire applicator right against your dog’s skin. Allow it to dry at least 24 hours before letting your dog get wet. It must be applied in a spot that your dog can’t reach to lick it, which is why between the shoulders is the recommended location. Frontline Plus Flea & Tick is approved for use on dogs and puppies as young as eight weeks, with a weight over 5 pounds, but be sure to check the label for the appropriate formula for your dog's weight.

Made with two active ingredients, Frontline Plus is a versatile treatment that can both address an infestation and prevent future ones. Fipronil kills adult fleas and ticks, while (S)-Methoprene disrupts their reproduction, killing flea eggs and larva.

_{Application Type: Topical | How Fast It Works: n/a | Requires Prescription: No | Active Ingredient: Fipronil and (S)-methoprene}

Courtesy of Amazon

View On Amazon View On Chewy View On Walmart

What We Like

Works within 30 minutes
Suitable for puppies as young as four weeks old

What We Don't Like

Only kills adult fleas

This fast-acting chewable treatment starts killing fleas within just 30 minutes, and is more than 90 percent effective within four hours. It can be used on dogs and puppies that weigh at least 2 pounds and are more than four weeks old.

Capstar Fast-Acting Oral Fleat Treatment only kills adult fleas and doesn’t affect eggs or larvae. It also doesn’t kill ticks. It can be used in conjunction with flea shampoos or sprays to offer quick relief. You actually can see fleas fall off your pet. This makes Capstar a good option if you have a puppy that is too tiny for longer-lasting treatments, or a new dog with an unknown flea history, allowing you to deal with their short-term discomfort while waiting for longer-lasting methods to take effect.

_{Application Type: oral | How Fast It Works: within 30 minutes | Requires Prescription: no | Active Ingredient: nitenpyram}

Chewy

View On Chewy View On 1-800-PetMeds View On PETCO

What We Like

Lasts as long as 30 days
Kills fleas, ticks, and lice
Waterproof

What We Don't Like

Chemicals can be irritating
Messy to apply

This spray works quickly and lasts for a long time, even if your dog goes swimming or gets a bath. In addition to taking out fleas, Frontline Spray is also effective against a variety of tick species, including brown dog ticks, American dog ticks, lone star ticks, and deer ticks, which are one of the main carriers of Lyme disease. The spray is also formulated to kill chewing lice.

Use household latex gloves when applying. Ruffle your dog’s coat while spraying a fine, even mist all over, until hair is damp to wet. Massage so that the product gets down to the skin and is evenly distributed. Avoid getting it in your pet’s eyes and mouth. Reapply every month.

The product can be used on dogs (and cats) that are at least eight weeks old. It stays waterproof for approximately 30 days, even if your pet gets wet.

_{Application Type: spray | How Fast It Works: less than 24 hours | Requires Prescription: no | Active Ingredient: Fipronil}

Adams Plus Flea & Tick Shampoo with Precor

Amazon

View On Amazon View On Chewy View On Walmart

What We Like

Kill fleas, eggs, and larvae, as well as ticks and lice
Soothes and moisturizes skin
Works for up to 28 days

What We Don't Like

Some dogs react to chemicals
Includes ingredients potentially harmful to cats

This popular flea shampoo is targeted to kill fleas, eggs, and larvae, as well as ticks and lice. Chemicals can be harsh, but this formula also contains oatmeal, aloe, lanolin, and coconut extract to help soothe and moisturize skin.

“Flea shampoo will kill most of what's on them, but does not prevent fleas from coming back. It should only be used if your dog has fleas, but hopefully they are on some type of preventative,” says Kim Flatley, professional dog groomer and owner of St. Louis-based Fitness with Fido.

The shampoo can be used every 7-10 days to kill fleas throughout their cycle, but it prevents flea development for as long as 28 days. It’s approved for dogs as young as 12 weeks, but confirm with your vet before using it on young puppies. For best results, wet your dog, lather the shampoo throughout coat and skin, then wait five minutes before rinsing thoroughly.

While Adams Plus Flea & Tick Shampoo is also intended for use with cats and kittens over 12 weeks, it would be best to consult with a veterinarian first. Pyrethrins, an active ingredient found in the shampoo, is a form of pesticide which can be dangerous to cats. While the Adams Plus shampoo is formulated to be safe for your cat if used properly, the potential for ingestion or accidentally getting some in your cat's eye warrants caution.

_{Application Type: shampoo | How Fast It Works: n/a | Requires Prescription: no | Active Ingredient: pyrethrins}

The 8 Best Flea Shampoos for Dogs of 2023

Final Verdict

Frontline Plus Flea & Tick Treatment for Dogs is a popular, long-lasting topical solution for fleas and ticks. If you need an immediate solution for a young puppy or while waiting for oral pills to kick in, Capstar (view at Chewy) is a fact-acting choice.

Age and Size Recommendations

Some flea and tick treatments like pills and spot-on applications are dosed depending on your pet’s weight. Make sure you purchase the right formula accordingly. Most treatments can be used on puppies that are at least 8 to 12 weeks old, but Capstar is approved for puppies as young as 4 weeks old. If you’re not sure, ask your vet.

Application Type

Flea and tick treatments can be shampoos or sprays or solutions that you squeeze on your dog’s back. There’s also a very effective array of prescription pills—usually a tasty chew—that your dog takes once a month. Many of the oral treatments also protect against intestinal parasites as well.

Choose the treatment type based on effectiveness, convenience, and any extra factors, like your pet’s medical history and the pests in your area. Your vet will help you decide.

Pests Targeted

The most effective treatments kill adult fleas as well as their eggs and larvae, in order to break the flea growth cycle. Some are effective against ticks, but check the label to make sure they are the pests in your area. Brown dog ticks are everywhere in the United States, for example, but lone star ticks are only in the southeastern and eastern United States. Make sure the product you choose fights the threats in your region.

FAQ

Are oral flea treatments safe for dogs?

Any flea treatment or preventative that has been approved by the FDA is safe and effective for the majority of dogs, said veterinarian Joanna Woodnutt of SeniorTailWaggers.com.
But there are always exceptions.
“For instance, many oral flea and tick preventatives contain a class of drugs called isoxazolines. Whilst they don’t cause seizures, these drugs may reduce the seizure threshold in some dogs, so if your dog is already prone to seizures this medication isn’t suitable for them,” Woodnutt told The Spruce Pets. This class of drugs is generally not recommended for dogs with neurologic disorders, or breeds with the MDR-1 gene mutation, such as Australian shepherds.
“The safety of a drug choice is one of the reasons that it’s a good idea to talk to your veterinarian about flea and tick treatment—they are best placed to help you assess the risks to your dog and come up with the best, safest, and most effective option.”
What is the best flea and tick treatment pill?

There are many prescription oral pills that treat and prevent flea and ticks on your dog, but the best treatment depends on your individual dog. Modern pills from the isoxazoline class (including Bravecto, Credelio, Nexgard, and Simparica) are “very reliable flea and tick treatments,” said Woodnutt.
“Which one you choose depends on the length of coverage you need (for example, Capstar is quick acting but only lasts 24 hours, so it needs following up with additional solutions), which weight range suits your pet, whether your pet is still growing, and whether your pet has underlying conditions or other medications that need to be considered,” Woodnutt said.
Some, like the monthly chewable Simparica Trio, are also combined with dewormers.
“The choice of the right treatment therefore also depends whether your dog would benefit from the combination treatment, or whether this would be doubling up on medications like heartworm preventative or dewormer,” Woodnutt told The Spruce Pets. “These are all things your vet will consider when helping you choose a good flea treatment protocol.”
Are cat flea and tick treatments safe for dogs?

According to Woodnutt, it’s never a good idea to use a medication targeted for one species on another.
“Differences in the drugs used and the concentrations in the medication mean that using cat treatments on the dog is not safe,” she said. “At best, they may be ineffective, causing a flea infestation or allowing a tick to spread disease to your dog. At worst, they can be dangerous, as cats and dogs are allergic to different drugs.”

For this roundup, we consulted with veterinarians, groomers, and researched what respected veterinary, pet, and government organizations say about flea and tick treatment. We avoided recommending prescription products because, although these are often most effective, they are something you should discuss with your veterinarian.

This article was researched and written by Mary Jo DiLonardo who has covered animals and pets for several decades. DiLonardro has fostered more than three dozen puppies and dogs and is always searching for the healthiest and most effective products to use on them.

The 8 Best Flea and Tick Prevention Products for Dogs of 2023

The 4 Best Flea and Tick Treatments for Dogs

Best Topical

Frontline Plus Flea & Tick Large Breed Dog Treatment

Best for Puppies

Capstar Fast-Acting Oral Flea Treatment for Dogs

Best Spray

Frontline Spray

Best Shampoo

Adams Plus Flea & Tick Shampoo with Precor

What to Look for in Flea and Tick Treatments for Dogs

Age and Size Recommendations

Application Type

Pests Targeted

Why Trust The Spruce Pets?

More from The Spruce Pets