Flea and tick prevention products aren’t just important for your dog’s comfort and health—they can also prevent the spread of flea and tick-borne illnesses.According to Dr. Gail Sommers Wolfe, D.V.M., untreated flea infestations can lead to health issues as serious as anemia or even death, while ticks “can transmit Lyme disease, Rocky Mountain Spotted Fever, Anaplasmosis, and Ehrlichiosis to humans.”
A variety of preventative treatments can minimize these risks in advance of your dog’s contact with parasites, and they come in diverse forms, including pills, chews, ointments, and shampoos (you can check out our favorite flea shampoos here).
Our favorite flea and tick preventative treatment is Simparica Chewables for Dogs, which combines a chewable, liver-flavored treat with sarolaner, a newly developed anti-parasitic approved by the U.S. Food and Drug Administration in 2016. Research indicates that it’s safe, and more effective than similar ingredients.
Simparica Chewables for Dogs
Available in a wide range of doses, based on your dog’s weight
Cutting edge antiparasitic ingredient
Minimal side effects
Proven effective against more tick species than other brands
Requires a prescription
Not available in single-month supplies
Not suitable for dogs under 6 months old
Simparica Chewables are liver-flavored tablets that provide a full month of protection from fleas and ticks with a single dose. Using a Simparica chewable is straightforward—there’s no need to give it to your dog with food, and it has a tested efficacy of 35 days.
Simparica kills fleas that are already on your dog within four hours of your dog eating the chewable. It is effective at curbing an infested household too, since Simparica kills fleas faster than they can lay eggs, disrupting the life cycle.
Similarly effective against ticks, Simparica will kill ticks on your dog within 24 hours—fast enough to potentially prevent transmission of diseases like Rocky Mountain spotted fever or Lyme disease. In one study of 24 dogs, the active ingredient in Simparica retained its efficacy throughout the month, outperforming the active ingredient in NexGard Chewables.While conducted according to guidelines established by the World Association for the Advancement of Veterinary Parasitology (WAAVP), it’s worth noting that the study was funded by Zoetis, the manufacturer of Simparica—a common practice that nevertheless presents a conflict of interest.
The active ingredient in Simparica, sarolaner, overloads the nervous systems of parasites by targeting a chemical pathway found in arthropods, but not mammals. Sarolaner is in the same class of chemicals as the afoxolaner found in NexGard and the fluralaner found in Bravecto, but was developed and approved more recently. It has been tested and found effective against a wider variety of ticks than some of its most popular competitors.
While side effects are typically mild and rare, you should keep an eye out for vomiting and diarrhea after giving your dog Simparica. The class of chemicals found in Simparica and similar treatments have also been linked to what the FDA calls in a 2021 fact sheet “neurologic adverse events in dogs and cats,” so it’s particularly important to seek medical attention if your dog has seizures, tremors, or trouble walking. Such side effects are rare enough that the FDA continues to describe this class of drugs as “safe and effective.”
Another potential downside of using Simparica is that it requires a veterinary prescription, though prescription drugs should be considered the primary method for warding off fleas and ticks.
Simparica is available in six different formulations, depending on your dog’s weight. Simparica is also available in 3-month, 6-month, and 12-month supplies.
Price at time of publish: $57 (3-month supply for medium-sized dog)
Delivery Method: Chewable | Active Ingredients: Sarolaner | Effective Against: Fleas and Ticks | Quantity: 3-, 6-, 12-month supply
Frontline Plus For Dogs Flea & Tick Spot Treatment
No prescription needed
Waterproof after 24 hours (although some sources recommend waiting 48 hours)
Kills fleas at all life stages
Available in three, six, eight, and twelve-count boxes
Leaves greasy spot on your dog’s skin
Not safe for use with cats
When it comes to warding off fleas and ticks, we recommend consulting with your veterinarian and seeking a prescription treatment. “Products prescribed by veterinarians are the best to use [for flea and tick prevention],” Dr. Wolfe told The Spruce Pets. “Veterinarians can advise which product would be best for your pet and how to use it properly.”
However, if you’re looking for a non-prescription solution, your best option is Frontline Plus. It’s a little more of a hassle to apply than a simple chewable, but it’s an well-tested, effective, and frequently veterinarian-recommended solution for killing ticks and fleas.
The active ingredients in this topical flea and tick treatment is fipronil, which kills adult fleas and ticks, and (S)-methoprene to kill flea eggs and larvae. By disrupting the flea life cycle at multiple stages Frontline can help reduce local infestations, preventing your dog from picking up fleas over and over. It’s also effective for chewing lice and sarcoptic mites.
To apply Frontline, you snap open a little tube, then squeeze out the contents onto a patch of skin between your dog’s shoulder blades—a spot where they’re not able to lick. The formula is absorbed through the oil glands and provides a full month of protection. Be sure to keep your dog dry for at least 24 hours after application to ensure the product has soaked in. After that, it’s safe for your dog to go swimming or be around other pets and children.
Price at time of publish: $37 (3-month supply for medium-sized dog)
Delivery Method: Topical | Active Ingredients: Fipronil and (S)-methropene | Effective Against: Fleas in all stages, ticks, chewing lice, and sarcoptic mites
Best for Puppies
NexGard Soft Chew for Dogs
Easy to administer bite size chews
Effective against fleas and ticks
Enticing beef flavor
Works for puppies as young as eight weeks
Safe for households with other pets and children
Requires a prescription
Has not been well-researched for use with pregnant dogs
The NexGard Soft Chew for Dogs is very similar to our top pick—a highly effective chewable given once a month. We think NexGard is a great choice for most dogs, and only prefer Simparica because of its recently developed active ingredient—which research indicates may be more effective—and because Simparica tends to be more affordable.
The main differences are that NexGard is beef-flavored instead of liver-flavored and can be used in puppies as young as eight weeks, as long as they weigh four pounds or more—Simparica is only recommended for dogs that are six months or older.
Afoxolaner, the chew’s main ingredient, is absorbed into the bloodstream after ingestion to kill fleas before they have a chance to lay eggs, and ticks, including the Lone Star, black-legged, American dog and brown dog varieties.
NexGard is FDA-approved and effective in preventing infections that cause Lyme disease. Unlike with some topical treatments, it’s okay if your dog gets wet immediately after ingesting the chews, plus they are safe to use with other pets and children in the household. Available in four types depending on the size of your dog, these chews are ideal for puppies as young as eight weeks weighing at least four pounds.
While NexGard is safe for use with most dogs, potential side effects to watch for include vomiting, diarrhea, lethargy, loss of appetite, and itching. Its use for pregnant dogs has also not been studied, which is also true of other drugs in this class, like the sarolaner in Simparica. NexGard recommends that people take particular caution when using NexGard with dogs who have a history of “seizures or neurological disorders.” NexGard has released a PDF with more complete prescribing information, which you can share with your veterinarian.
Price at time of publish: $75 (3-month supply for medium-sized dog)
Delivery Method: Chewable | Active Ingredients: Afoxolaner | Effective Against: Fleas and ticks
Adams Plus Flea & Tick Shampoo with Precor
Kills adult fleas, eggs and larvae, as well as ticks and lice on contact
Leaves coat soft and shiny
Known for its clean, fresh scent
May not prevent re-infestations as well as advertised
May not be safe for use with cats
No prescription needed
Adams Plus Flea & Tick Shampoo combines the active flea and tick-killing ingredients pyrethrin, s-methropene, and butoxide with itch and skin-soothing ingredients like aloe, oatmeal, lanolin and coconut extract for a creamy, lightly-scented formula.
Great for sensitive-skinned pups, Adams Plus and can be used as-is or diluted with 2 parts water if needed to create a better lather. A little goes a long way, too— instructions say that 1⅓ tablespoons is all you need per five pounds of pet weight.
Available in 12-ounce, 24-ounce, or gallon-size containers, this shampoo is safe for dogs and puppies of 12 weeks and older—but you’ll want to be careful not to apply near the eyes.
While effective at killing fleas, we’re less convinced of its preventative effectiveness. Adams Plus contains an insect growth regulator that the manufacturer claims can prevent flea development for up to 28 days. However, Dr. Melissa Hall, Dutch vet specialist and board certified veterinary dermatologist advised that the shampoo is better used in conjunction with other preventative treatments, telling The Spruce Pets that it’s "good for a current infestation but will not be an effective preventative."
While Adams Plus Flea & Tick Shampoo is generally considered safe for use with cats, we recommend against it, since cats are sensitive to the active ingredient pyrethrin.
Price at time of publish: $15
Delivery Method: Topical | Active Ingredients: Pyrethrins, s-methropene, and piperonyl butoxide | Effective Against: Fleas at all stages, ticks, and lice | Size: 12 ounce bottle
Best for Worms Too
Simparica Trio Chews for Dogs
Convenient combination of several medications in one
Great for long-haired/thick-haired dogs where topicals are more difficult to apply
Effective against heartworm, roundworm, hookworm, fleas, and 5 kinds of ticks
Provides a full month of protection
Most dogs love the liver flavor
Only available with prescription
May be unnecessary if your dog is already treated for heartworms
Only available in 6 and 12-month supplies
Simparica Trio offers the same long-lasting, effective protection against ticks and fleas as Simparica, but also includes active ingredients for preventing worms. Consisting of sarolaner, moxidectin, and pyrantel (the trio), these medications work together to prevent heartworm, hookworm, and roundworm, protect against flea infestations, and also guarding against five types of ticks: the Lone Star tick, Gulf Coast tick, American Dog tick, black-legged tick, and Brown Dog tick.
A convenient alternative to buying and administering several different medications, these all-in-one chews come in packs of three. Each dose is effective for a full month, and works for a range of dog sizes including puppies of at least eight weeks of age weighing a minimum of 2.8 pounds. They come in liver-flavored bites.
Price at time of publish: $162 (6-month supply for medium-sized dog)
Delivery Method: Chewable | Active Ingredients: Sarolaner, moxidectin, and pyrantel | Effective Against: Fleas, ticks, heartworm, roundworm, and hookworm
Best Area Treatment
Harris Food Grade Diatomaceous Earth
Creates a barrier against fleas, ticks, roaches, and other pests
Organic and food grade quality
Can be used indoors or outdoors
Free of harmful chemicals
Comes with a powder duster
Available at a wide range of retailers
Effectiveness is decreased when wet
Diatomaceous earth is a powdered sedimentary rock containing the fossilized remains of microalgae known as diatoms. Because it is mildly abrasive and highly absorbent, this powder has several practical applications, including as an insecticide. Diatomaceous earth kills fleas, ticks, bedbugs, cockroaches, and other pests by disrupting the waxy outer layer of their exoskeletons and dehydrating them.The powder can be spread anywhere to form an anti-parasite border, plus it is harmless to humans and pets.
We prefer Harris Diatomaceous Earth because it contains zero additives, is registered with the Organic Minerals Research Institute (OMRI), and is both mined and packaged in the United States. It also comes with a powder duster in the bag, which lets you spray powder into the crevices alongside refrigerators and other hard-to-reach places.
You can spread this diatomaceous earth practically anywhere, such as by dusting carpets, surrounding the legs of furniture, placing in corners, or spreading in your yard and garden. It’s best to target problem areas, since the light powder needs to be reapplied occasionally.
Harris Diatomaceous Earth is available in a four pound bag. 10 percent of profits are donated to the Etowah Valley Humane Society in Georgia.
Price at time of publish: $15
Delivery Method: Powder | Active Ingredients: Organic, food grade diatomaceous earth | Effective Against: Fleas in all life stages, ticks, cockroaches, bedbugs, carpet beetles, spiders, ants, centipedes, and more
TropiClean Maximum Strength Natural Flea & Tick Dog Shampoo
Effective against fleas, ticks, and mosquitos
Natural citrus scent
Works on puppies as young as 12 weeks
Must be used frequently
Can cause eye irritation; must be careful to avoid eyes, nose and mouth when bathing
Repel fleas and ticks naturally with your dog’s bath when you suds them up with this product. An excellent choice for sensitive-skinned dogs, Tropiclean Natural Flea and Tick shampoo is equipped with several natural EPA-approved flea, tick, and mosquito repellents, including lemongrass oil, clove oil, cedarwood oil, cinnamon oil, and moisturizing sesame oil. Not only does it work to help kill parasites (adults as well as larvae and eggs) on contact, the Maximum Strength variety also smells fresh and citrus-y for up to a week after use.
An added benefit is its soap-free quality, using a coconut cleanser to get your pup clean without rinsing away any topical treatments you may have applied prior to bathtime. It also comes in spill-resistant packaging so you won’t waste any if it tips over. Available in 20-ounce or gallon-size shampoo bottles, as well as a spot treatment, collars, home, bedding, and yard sprays, you can choose to add what works best for your household.
Price at time of publish: $16
Delivery Method: Topical (shampoo) | Active Ingredients: Lemongrass oil, cedarwood oil, cinnamon oil, clove oil and sesame oil | Effective Against: Fleas, ticks, and mosquitos
Seresto Flea & Tick Collar for Dogs
Easy to use
Effective against fleas, ticks, and lice
Provides 8 months of protection
Available in large and small sizes
Loses effectiveness if your dog swims or bathes a lot
Not for use on cats
Flea collars have mostly been superseded by newer products like chewables, but if you want to use a flea collar on your dog, we recommend the Seresto Flea and Tick Collar. It’s effective, easy to fit, and lasts for a whopping eight months. That’s why we named it our favorite overall flea collar.
Safe for most adult dogs, the Seresto Flea and Tick Collar for Dogs surpasses the efficacy of most flea collars, efficiently targeting all life stages of the parasites. Each collar contains the active ingredients imidacloprid and flumethrin combined into a controlled release formula which starts working within 24 hours. Seresto collars provide coverage across your dog’s entire body.
The formula used in Seresto collars kills fleas and ticks on contact for up to a full 8 months. It also kills sarcoptic mange and chewing lice. Plus, the collars are non-greasy and have no chemical odor.
Price at time of publish: $54
Delivery Method: Collar | Active Ingredients: Flumetrin and imidacloprid | Effective Against: Fleas of all life stages, ticks, chewing lice, and sarcoptic mange
Our favorite way to protect a dog from fleas and ticks is Simparica Chewables, which uses a safe and highly effective ingredient to provide a month of protection at a time—all your dog has to do is enjoy a treat. If you’d rather not seek a prescription, check out Frontline Plus for Dogs. It’s very effective and long-lasting, but you do have to apply it directly to your dog’s skin, making it a little more complicated to use than a chewable.
What to Look for in a Flea and Tick Prevention Product
There are several types of flea and tick prevention products that are popular today, including topicals, oral tablets, shampoos, sprays, and collars. Topical formulas are liquids that are either sprayed on the skin and fur or applied to the back of your dog's neck, while oral tablets are designed to be eaten—oral medications are preferable if your dog frequently gets wet, which can wash off topical treatments, but they're often more expensive than topicals. Shampoos often need to be reapplied several times per month. Wipes and collars may also be used, while some treatments may be applied to the ground outside or to floors and bedding inside.
Most flea and tick prevention products contain some type of insecticide that targets either the living flea or its eggs. It's best to talk to your veterinarian to figure out which ingredients will work best for your dog.
Some commonly used ingredients that kill fleas and ticks include:
- Fipronil: Found in products like Frontline and PetArmor, this chemical kills on contact by disrupting the insect’s central nervous system.
- S-methoprene: Sometimes referred to by a trade name, Precor, this chemical is an insect growth regulator which disrupts the hormone levels of insects rather than killing them.
- Afoxolaner: This chemical induces the death of parasites after brief exposure. Causes hyperexcitation by attacking the insect’s central nervous system. Fond in NexGard.
- Sarolaner: Found in products like Simparica, this chemical works after ingestion and inhibits certain neurotransmitters and other receptors.
- Selamectin: Found in products like Capstar and Selarid, this causes overexcitement of the nervous system leading to paralysis and death.
- Permethrin: Contained in products like K-9 Advantix and Bio Spot On, this causes spasms, paralysis and death by disrupting the nervous system of parasites.
- Lotilaner: Found in products like Credelio, this chemical kills parasites by impacting the nervous system after being ingested.
- Flumethrin: Found in products like Seresto flea collars, this chemical disrupts the transmission of nervous impulses in parasites.
- Deltamethrin: Found in products such as Frontline, this works after contact or ingestion by interrupting the central nervous system.
- Fluralaner: Found in products like Bravecto, this chemical targets the nervous system and kills fleas before they can lay eggs.
Longevity/Frequency of Use
Different flea and tick products are effective for different lengths of time. Some need to be reapplied every week or more, while others might a month or longer. Not only will this affect how often you need to re-administer the treatment, but it will also dictate how much you'll spend on flea and tick treatments each year.
The efficacy of flea and tick preventative products can depend on several factors, including the drug's "half-life," which is a measure of how long it takes before the amount of a specific drug in your dog's blood system drops to half its initial load. However, doses are often designed to compensate, so even if a drug's half-life is two weeks, it's likely designed to still be an effective dose beyond that point.
Certain products are also susceptible to wear, such as topical treatments that adhere to your dog's skin, but may slowly rinse away during bathing or swimming.
How can you tell if your dog has fleas?
There are several telltale signs that your dog might have fleas. If you notice that your dog is itching more than usual, particularly at its flank or above its tail, you'll want to check to see if you can spot any of these little bugs in its coat. If you part your pet's fur, you'll often be able to see "flea dirt," which looks like tiny black specks, or even black bugs that may jump away.
How can you prevent your dog from getting fleas?
In addition to using a flea and tick prevention product on your dog, there are a few ways you can reduce their risk of getting fleas. Fleas prefer to live in shaded outdoor areas with sand, leaves, or other debris, so you can help prevent fleas by keeping your grass cut short and keeping your dog from playing in areas where fleas might be hiding. You can also treat your home and yard with food grade diatomaceous earth, which helps to kill adult fleas and ticks.
Can most flea treatments be used on puppies?
In general, puppies should only be given flea treatments after they're weaned—typically around seven or eight weeks of age. It's important to check the age range on the flea treatment you're using to see if it's safe to use on your puppy. Your vet will also be able to recommend an appropriate treatment for your young dog.
"The pet’s size is important to consider. For instance, for our itty-bitty dogs (like teacup Chihuahuas or Yorkies) a smaller size option is necessary and for giant breed dogs, we may need to give two different sizes to make sure we are getting to a therapeutic dosage," Dr. Hall says.
She adds that veterinary guidance can be crucial in the safe administration of these products because, without it, “they can cause irritation to the skin and eyes, and when used injudiciously, they can also cause infertility.”
Why Trust The Spruce Pets?
This article was researched and written by KJ Callihan, a writer for The Spruce, who has worked in animal shelters, helped socialize animals for adoption, and fostered animals of various kinds. She also writes for CNET, AAA Northeast magazine, and more.
This roundup was written in consultation with experts, including Dr. Gail Sommers Wolfe, D.V.M., of her own private practice: Bennett Road Animal Clinic in Okemos, Michigan. We also spoke with Dr. Melissa Hall, a Dutch vet specialist and board certified veterinary dermatologist. In addition, we followed guidance provided by the FDA.
An older version of this article was written by Anne Fritz, a freelance lifestyle writer with over 20 years of experience.