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

By K9 Advantix II
Rated 4.3385 out of 5 stars
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K9 Advantix II Flea & Tick Spot Treatment for Dogs, 11-20 lbs,12 Doses (12-mos. supply) slide 1 of 8
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K9 Advantix II Flea & Tick Spot Treatment for Dogs, 11-20 lbs,12 Doses (12-mos. supply) slide 1 of 8

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Rated 4.3385 out of 5 stars
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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%....Active Ingredients: Imidacloprid 9.10%, Pyriproxyfen 0.46%.Dinitefuran, Pyriproxyfen, Permethrin.Active Ingredients: Imidacloprid 8.80%, Permethrin 44.00%, Pyriproxyfen 0.44%....Active Ingredients: Imidacloprid 8.80%, Permethrin 44.00%, Pyriproxyfen 0.44%...
LifestageAdult, Puppy, SeniorAdult, Puppy, SeniorPuppy, Adult, SeniorAdult, Puppy, SeniorAdult, Puppy, Senior
Breed SizeSmall BreedsSmall BreedsSmall 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 4.3385 out of 5 stars
839 Reviews
Would recommend to a friend

839 Customer Reviews

Rated 5 out of 5 stars
By kristy on Jul 29, 2022

FLEA meds bundling

I'm delighted at your savings offer to allow bundling K9 Flea meds for my small dogs and large dogs. It's great that you stock the items I use to protect my dogs from Mosquitos and Fleas for the Summer Great delivery, fast service. I appreciate your quality products that may be unavailable at local stores in our area. Thanks a happy customer.

Rated 5 out of 5 stars
By LabLover on Jul 30, 2022

Effective killer

We have a big Lab and small Schipperke. We use this on both and it kills the fleas like right now. Dead and gone. Just the way I like it for fleas. The key is to get it on the bare skin, which can be a chore with double coat breeds. Both my pups get almost instant relief from the itch and stop scratching.

Rated 2 out of 5 stars
By Scardiary on Jun 10, 2022

What happened

I used this product on my 4 dogs all last season with no issues. This season we started them on it in March to get ahead of the flea season and it is not working as advertised. I have been finding fleas on my dogs daily and have even pulled a few ticks off of one of them. This has led me to have to bomb my home and start all over again with a different brand of flea med. Not sure I will ever buy this brand again. Did the formula change at some point; if so change it back! For what I paid I expect to have good results.

Rated 1 out of 5 stars
By Delores on Jun 3, 2022

I can't recommend this since my dog had a reaction to it.

My dog has changed in demeanor since I applied K9Advantix II. He has become worried and scared of things and also seems more sleepy. I contacted my vet. There's nothing to be done at this point. There is nothing else new or different and I can only attribute it to this product. I'll not use this top spot again which means I've wasted a box of it. I'll use Geranium essential oil instead.

Rated 1 out of 5 stars
By Worthless on Jun 9, 2022

Both dogs still had fleas after 6 months

Both dogs still have fleas after 6+ months of use and fleas keep coming back. We've tried additional products to this flea medicine, but it's as though this flea medicine is doing absolutely nothing. This product does not work well. Very frustrating. Do not recommend

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 Amelia on May 23, 2022

Nope, not at all

This stuff didn't even last a day. The herbal stuff works better and that barely works at all. Waste of money that I don't have to waste. My dog still picks up 15 to 30+ fleas every walk and they like me too.

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 NinaJo on Jul 9, 2022

Chewy rocks!

It’s nice to have a dependable company with quality control; excellent communication; & dependability.

Rated 2 out of 5 stars
By jack on Jul 28, 2022

Flea and tick

The treatment made him scratch himself crazy for 3 days. I'm afraid to use it again.