K9 Advantix II Flea & Tick Spot Treatment for Dogs, 11-20 lbs

By K9 Advantix II
Rated 4.3555 out of 5 stars
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K9 Advantix II Flea & Tick Spot Treatment for Dogs, 11-20 lbs, 6 Doses (6-mos. supply) slide 1 of 9
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K9 Advantix II Flea & Tick Spot Treatment for Dogs, 11-20 lbs, 6 Doses (6-mos. supply) slide 1 of 9

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About This Item

  • Broad-spectrum, veterinarian-recommended treatment repels and kills fleas, ticks and mosquitoes on dogs 7 weeks or older and weighing 11-20 pounds.
  • Begins working within 12 hours and kills pests on contact.
  • Kills all life stages of fleas to prevent re-infestation; also kills lice and even repels biting flies.
  • Waterproof formula continues working for up to four weeks, even after bathing or swimming.
  • Convenient, monthly topical application contains imidacloprid, permethrin and pyriproxyfen; available in packs of 2, 4 or 6 treatments.
Play Video: Learn More About K9 Advantix II From Our Team of Experts
Learn More About K9 Advantix II From Our Team of Experts

Important Information

Fleas rise to the top of your pet's coat as they die, so consider it a triumph if you start seeing more fleas at first, after treating your pet. If you’re still seeing fleas after application, it may be because your pet has picked up new fleas from the environment, which may include other pets, surfaces and outdoor areas. It may take up to 30 days to break the entire flea life cycle. Additionally, you should also treat sources of new fleas (i.e., carpet, yard, etc.) to ensure complete flea control.

About K9 Advantix II

Experience the Advantages of K9 Advantix II

Veterinarian-recommended K9 Advantix II kills fleas, ticks, mosquitoes and lice, and repels biting flies. Now you can help your dog fight these pesky pests through contact—no biting required. Convenient and easy to use, K9 Advantix II is for dogs and puppies 7 weeks of age or older. So help your pal get the effective protection he needs with all of the advantages of K9 Advantix II.

Why are Biting Bugs a Big Deal?

K9 Advantix II spreads over the skin and hair to kill and repel them through contact, meaning they do not have to bite to die. And if a flea, tick or mosquito is repelled, it cannot bite and transmit disease.

Why Choose K9 Advantix II?

Fleas, ticks and mosquitoes can negatively affect your pet's health. It's important to use an effective product that kills pests which can spread disease. Fleas can cause flea allergy dermatitis, an allergic reaction that can lead to constant scratching, severe itching and even hair loss. Ticks can transmit deadly diseases, such as Lyme disease and Rocky Mountain spotted fever. And mosquitoes can potentially carry dangerous diseases, too, including heartworm. K9 Advantix II should not be used in place of a heartworm disease prevention product.

Is K9 Advantix II the Right Choice for Your Dog?

Whether your dog is a winter snow hound or a summer backyard explorer, an sunseeker or an outdoor enthusiast, choose K9 Advantix II to help keep fleas, ticks and mosquitoes from interrupting his favorite activities year-round. If you want to return the love to your dog, take care of him with flea prevention that works to kill the fleas you see and the ones you don't.

K9 Advantix II Has a Treatment for Dogs Large and Small


4-10 pounds


11-20 pounds


21-55 pounds


55 pounds and over

Do not use K9 Advantix II on cats.

About K9 Advantix II

K9 Advantix II is manufactured by Bayer, a leading name in the healthcare industry for over 150 years. K9 Advantix II is a monthly flea, tick and mosquito treatment for your dog that kills through contact—no biting required. It starts working to kill fleas within 12 hours of application and is veterinarian recommended, so you can feel confident knowing that your pet is getting effective protection.
Shop Bayer

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Top IngredientsActive Ingredients: Imidacloprid 8.80%, Permethrin 44.00%, Pyriproxyfen 0.44%....Dinitefuran, Pyriproxyfen, Permethrin.Active Ingredients: Imidacloprid 8.80%, Permethrin 44.00%, Pyriproxyfen 0.44%....Dinitefuran, Pyriproxyfen, Permethrin.Fipronil: 6.0%, Permethrin: 44.8%, Pyriproxyfen: 1.8%...
LifestageAdult, Puppy, SeniorPuppy, Adult, SeniorAdult, Puppy, SeniorPuppy, Adult, SeniorAdult
Breed SizeSmall BreedsSmall BreedsExtra Small & Toy BreedsExtra Small & Toy BreedsSmall Breeds, Medium Breeds

Questions & Answers

31 Customer Questions

I see a lot of reviews for fleas but I have a trouble with ticks. How good is this at preventing and killing ticks?
Answer by ChewyMar 13, 2018
This product repels and kills ticks including Deer ticks, American dog ticks, Brown dog ticks, and Lone Star ticks for up to 4 weeks.

What's the expiration date? I can't find it on the box?
Answer by ChewyMar 19, 2018
This product does not have an expiration date. It will be safe to use as long as you store unused containers in their original packaging and at room temperature.

does it kill the eggs and mosquitos
Answer by ChewyMar 25, 2018
The Treatment kill fleas of all stages and also repels and kills mosquitoes.

Can this product be used at the same time as heartworn medications
Answer by ChewyOct 23, 2017
We'd recommend speaking with your veternarian before applying this treatment while using heartworm medication.

ReviewsWrite a Review

Rated 4.3555 out of 5 stars
827 Reviews
Would recommend to a friend

827 Customer Reviews

Rated 5 out of 5 stars
By Sloopy on Apr 24, 2022

Been using it for years

I've been using this for years, mostly because it also repels in addition to killing. We live in a large city where fleas can be a problem and go for a lot of hikes where ticks are abundant. Nothing is ever full proof, but in over 9 years of use on 3 different dogs, I've only had to pull maybe 3 or 4 ticks and have only ever found 1 half-dead flea. So I consider it well worth the cost. I can't say how it works for an active infestation, but it's great at preventing one from ever starting

Rated 1 out of 5 stars
By Amye33 on Apr 13, 2022


My Pomeranian has fleas for the 2nd time in 7 years and she is miserable! I understand with her coat that all of the med may not have penetrated her skin. (I know some did) But because of her double coat it's tough. However it's like they're worse!

Rated 5 out of 5 stars
By Lori26 on Apr 13, 2022

Flea and Tick

The best flea and tick and everything else it says for dogs—- and we live in Florida and Mountains, Appalachians. Been using it for years and one of my dogs that I adopted has sores. They disappeared after using this. Excellent product!

Rated 5 out of 5 stars
By capmark on Apr 27, 2022

Chewy Rocks !

This topically applied product is nice and uncomplicated unlike the newer combo choices. My dogs are to important to me to fill them with multi drugs.

Rated 5 out of 5 stars
By Glenda on May 19, 2022

Brody uses every month

This works So great have used it for years just wish it was a little cheeper but great product thank you chewy

Rated 5 out of 5 stars
By Frankie on May 22, 2022

Fast shipping

I have used the K9 Advantix II for the past 4 years, was advised by my dogs groomer to use this brand.

Rated 4 out of 5 stars
By Nette on Dec 23, 2021

ordered but have not received yet

Ok, so I have been using spot ons for years. Frontline plus, however I am going to use this product for my German shorthair puppy. I live in Southern CA, fleas here most of the year. I researched why flea meds don’t work, and found out either user error, fleas adapt and build a resistance, or some dogs have thick coats with A lot of hair and the spot on may not work as well. I would probably use an internal pill and a spot on in that case. I read you can use multiple methods of flea treatment if your dog has a bad infestation and spot on alone is not enough. My dogs have very short hair, so spot ons alone have always worked. I will write a review of the product after 30 plus days and see if this still holds true

Rated 5 out of 5 stars
By Adam on Dec 12, 2021

Works Great in PA

Our dogs picked up fleas after being boarded at a kennel for a few days. I tried shampooing them with two brands of flea shampoos and while they both worked to kill the live fleas, they didn't eradicate them completely by killing the eggs. I'd shampoo them then have live fleas again in a day or two. I read the reviews of this product and decided to give it a shot. I know some people down south had issues with the fleas adapting to the chemicals used in this treatment, but I am happy to report that it worked great in Pennsylvania. One dose knocked out our flea problem in a matter of days.

Rated 1 out of 5 stars
By Andy on Mar 22, 2022

K9 advantix

This product did not work for my furbaby it usually works and for some reason this time it has not worked and seems to digging more

Rated 5 out of 5 stars
By Kelley on Apr 13, 2022

Ordering monthly meds

Chewy made this easy and my order came quickly! I appreciate the lower costs as well.