The active ingredients on each flea and tick label we list, how often it goes on and which dogs it's for. Plus which ones need a prescription, and what to ask your vet.
Every flea and tick product here is a pesticide. Here is what's in each one. Seresto collar: imidacloprid and flumethrin. Frontline Plus: fipronil and (S)-methoprene. Adams Plus shampoo: pyrethrins, (S)-methoprene and piperonyl butoxide. Vet's Best spray: peppermint oil, eugenol and sodium lauryl sulfate. Chews need a prescription. Take this list to your vet and choose together.
In this guide
Collar, monthly drop, bath or a vet-prescribed chew: pick the one that fits your dog. Below: the active ingredients on each label, how often it goes on and which dogs it's labeled for. Every one is a pesticide, so the final call is a short chat with your vet.
Chews (NexGard, Simparica, Credelio, Bravecto) are prescription only. Collars, spot-on topicals, sprays and shampoos are sold over the counter. Whatever you pick, don't combine two products without asking your vet first.
Chews (NexGard, Simparica, Credelio, Bravecto) are prescription only.
What's in each one, at a glance
Seresto collar: Imidacloprid and flumethrin. One collar lasts up to 8 months.
Frontline Plus topical: Fipronil 9.8% and (S)-methoprene 8.8%. Once a month.
Adams Plus shampoo: Pyrethrins 0.15%, (S)-methoprene 0.1% and piperonyl butoxide 1.88%. Used at bath time.
Vet's Best spray: Peppermint oil 0.30%, eugenol 0.70% and sodium lauryl sulfate 2.70%.
Prescription chews: Your vet prescribes these, so that conversation comes first.
Prescription or over the counter: what you can buy without a vet
The split is simple. Flea and tick chews are prescription drugs approved by the FDA, so they come through your vet. Collars, spot-on topicals and medicated shampoos are sold over the counter and regulated by the EPA as pesticides.
Plant-oil sprays can fall under EPA's minimum-risk category, which is exempt from federal registration.
The four over-the-counter options, label by label
Seresto collar: imidacloprid and flumethrin
Seresto Flea & Tick Collar. Active ingredients: imidacloprid and flumethrin.
What's in it: Two pesticide actives, imidacloprid and flumethrin.
How often: One collar lasts up to 8 months.
Labeled for: This listing is the large-dog collar, for dogs over 18 lbs and at least 7 weeks old. Dog collars go on dogs only.
Worth knowing: In February 2024, EPA's Office of Inspector General reported that EPA had not yet completed its registration-review risk assessments for pets for these ingredients.
Ask your vet: Does the collar suit your dog's size and health, and the other pets in your home?
Frontline Plus topical: fipronil and (S)-methoprene
Frontline Plus Flea & Tick Treatment. Active ingredients: fipronil 9.8% and (S)-methoprene 8.8%.
What's in it: Fipronil 9.8% and (S)-methoprene 8.8%, on the EPA-accepted label, EPA Reg. No. 65331-5.
How often: Once a month.
Labeled for: This listing is the 89 to 132 lb dose, in a box of 3. Weigh your dog before you order. Dog doses go on dogs only.
The label's own cautions: "Harmful if swallowed. Causes eye irritation." It also says to consult a veterinarian before using it on medicated, debilitated or aged animals.
Vet's Best Flea & Tick Spray. Active ingredients: peppermint oil, eugenol and sodium lauryl sulfate.
What's in it: Peppermint oil 0.30%, eugenol (from clove) 0.70% and sodium lauryl sulfate 2.70% as actives, with water and sodium benzoate (the maker's ingredient list).
Worth knowing: The maker calls it "Certified Natural" and names no certifier. You reapply a spray more often than a collar or a monthly topical.
Labeled for: Dogs 12 weeks and up, and the home. Let the coat dry before pets groom themselves or each other. Dog products go on dogs only, so keep it off cats.
Ask your vet: Is a spray enough where you live, or does it belong on top of a main preventive?
Flea control for the home: treat every pet, then the house
The fleas you see on your dog are the small part of the problem. Their eggs fall off into bedding, rugs and couch cushions, which is why a dog can pick up new fleas right after a treatment.
Treat every dog and cat in the home on the same day, each with a product labeled for that species. One untreated pet keeps the cycle going.
For a dog with fleas right now, ask your vet whether a flea bath fits first, then start the prevention they recommend, as the directions say.
Wash your dog's bedding, blankets and couch throws in hot water.
Vacuum floors, rugs and the couch, then empty the vacuum outside. Keep vacuuming every few days for the next few weeks, since new fleas keep hatching from the house.
Tick protection on walks: check your dog every time
Prevention lowers the odds, but a tick check after woods, tall grass or trail walks still matters. Run your hands over your dog and look closely at the ears, around the eyes, under the collar, the armpits, between the toes and around the tail.
Found one? Grip it with fine-tipped tweezers as close to the skin as you can and pull straight out with steady pressure. Skip the heat, nail polish and petroleum jelly. Clean the spot, and call your vet if it stays red or your dog seems off in the days after.
Long days on rough trails? Our guide to dog boots for paw protection covers the feet; the tick check still comes after.
When to start prevention: before the first scratch
Start before flea and tick season where you live, not after the first scratch. By the time your dog scratches, fleas are already laying eggs, and the eggs drop into the carpet, the dog bed and the couch.
Your vet knows when your local season starts.
Warm climates often need prevention all year. Ask your vet what your area needs.
Don't skip months: A gap gives fleas time to settle into the house.
Start sooner, or keep going longer, if:
Your dog swims, hikes or runs through tall grass or woods.
Your dog goes to daycare, boarding or the dog park.
Another pet in the house goes outside.
You're traveling somewhere warmer than home.
Make the schedule stick: pair every dose with a treat and a fixed date, like the first of the month. A dog who expects a snack holds still for a spot-on.
Questions to ask your vet before you choose
The right product depends on your dog, your area and who else lives with you. Bring these to the next visit:
Which parasites are common where we live: fleas, ticks, or both?
How often does my dog need a dose, and does that change in winter?
Which weight band and minimum age fit my dog?
Does my dog's health history, such as seizures, rule out any type?
We have a cat. Which dog products are risky around cats? Some dog-only products, such as those with permethrin, are toxic to cats.
Can I combine a collar, a topical and a spray, or is one enough?
What should I do if my dog reacts to a product?
If your dog scratches hard, drools or acts unwell after a new product, call your vet. For a topical, follow the wash-off directions on the box.
Which flea and tick prevention is right for my dog?
It depends on your dog's size, age and health, the parasites where you live, and who else shares the house. Take the label facts above to your vet and choose together.
Is there a plant-oil flea and tick option?
Some sprays use plant oils, such as Vet's Best with peppermint oil and eugenol (plus sodium lauryl sulfate). They are still pesticides, and the maker's "Certified Natural" names no certifier. Ask your vet whether one fits on its own or alongside a main preventive.
How do I know if my dog has fleas?
Signs include: excessive scratching, biting at the base of the tail, "flea dirt" (tiny black specks) in the coat, red irritated skin, and hair loss. To check, comb your dog with a fine-tooth flea comb over a white paper towel. If you see small dark specks that turn reddish when wet, those are flea droppings.
When does flea season start?
It depends on where you live. Fleas pick up as the weather turns warm and humid, and in mild climates they can be around all year. Start prevention before you see scratching, and ask your vet when the season starts locally.
When should I start flea prevention for a puppy?
Only use a product labeled for your puppy's age and weight. Ask your vet at the first checkup which product fits and when to start, then reweigh your puppy before each dose, since puppies change weight band quickly.
Which flea and tick medication needs a prescription?
Prescription chews include NexGard, Simparica, Credelio and Bravecto. The over-the-counter options on this page don't need one. Ask your vet which route fits your dog.
Why do I still see fleas after starting prevention?
Usually because new fleas are still hatching in the house, not because the product failed. Keep up the dose, treat every pet, wash bedding and vacuum often for a few weeks. Still seeing plenty of fleas after that? Ask your vet about switching.
Considered, didn't make it
Prescription chews (NexGard, Simparica, Credelio, Bravecto): prescription only, so they come through your vet, not a shop link.
Dog-only flea products: ask your vet before using one in a home with a cat.
Before you buy: bring this list to your vet
Each option here is a pesticide with named actives, and each suits a different routine: a collar for months, a monthly topical, a bath-day shampoo, or a spray you reapply. Bring this list to your vet with your dog's weight and a note on any other pets at home, and choose together.
