K9 Advantix II Flea & Tick Spot Treatment for Dogs, 11-20 lbs,12 Doses (12-mos. supply)

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About This Item

Details

  • Helps to protect dogs weighing 11 to 20 pounds from fleas, ticks, mosquitoes, biting flies and lice.
  • Starts working within hours of application.
  • Kills and repels on contact, so fleas don’t have to bite your furbaby to die.
  • Easy-to-apply topical treatment is fragrance-free and waterproof after 24 hours.
  • No prescription needed.

Ingredients

Instructions

Size

FAQ

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

K9 Advantix II Fights 5 Major Pests

K9 Advantix II protects against fleas, ticks, mosquitoes, biting flies, and lice. It kills fleas on dogs within 12 hours and continues to prevent infestations for 4 weeks. Do not use on cats.

How K9 Advantix II Works

The active ingredients in K9 Advantix II (imidacloprid, permethrin, and pyriproxyfen) spread over the skin. Fleas and ticks are killed through contact, so they don’t have to bite your dog to die.

Flea Treatment & Prevention

K9 Advantix II kills and repels fleas, ticks, and mosquitoes.

Kills & Repels

These flea drops kill adult fleas, flea larvae, and flea eggs to break the flea lifecycle.

Same-Day Effectiveness

K9 Advantix II kills fleas on dogs within 12 hours, and it keeps working for four weeks to prevent reinfestation.

No Prescription Needed

You don’t have to go to the vet to get quality flea and tick protection for your dog—simply buy and apply.

Fragrance-Free

This flea topical formula is fragrance-free and waterproof 24 hours after application.

Frequently Asked Questions

Can I use K9 Advantix II on My Dog?

K9 Advantix II is for dogs 7 weeks of age and older. This product comes in four sizes: Small Dog (4-10 lbs.), Medium Dog (11-20 lbs.), Large Dog (21-55 lbs.), and Extra Large Dog (over 55 lbs.). Choose the right size based on your dog’s weight, and do not use on cats.

How Do I Apply K9 Advantix II?

Break the seal on the tube, then part the hair along the top of your dog’s back and evenly apply the contents from the shoulder down to the base of the tail. The number of application spots will depend on the size and weight of your dog—refer to the product label for detailed instructions.

The Advantage Family

Get the Advantage over fleas with complete flea protection for your pet, home, and yard. The Advantage family of products has everything you need for a complete flea treatment and prevention plan, including monthly topical treatments, pet shampoos and sprays, household sprays for carpets and crevices, and even a yard and premise spray. Just be sure to get the right product for each need and use only as directed.

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Compare Similar Items

K9 Advantix II
Flea & Tick Spot Treatment for Dogs, 11-20 lbs,12 Doses (12-mos. supply)
K9 Advantix II
Flea & Tick Spot Treatment for Dogs, 11-20 lbs,12 Doses (12-mos. supply)
$148.20 Chewy Price
($12.35/ea)
Rated 4.4 out of 5 stars
3.4KReviews
Lifestage           
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All Lifestages, Adult
All Lifestages, Adult
Special Diet           
Indoor
Indoor
Indoor
Ingredients           
Active Ingredients: Imidacloprid 8.80%, Permethrin 44.00%, Pyriproxyfen 0.44%.
Active Ingredients: Imidacloprid 8.80%, Permethrin 44.00%, Pyriproxyfen 0.44%.
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Dinitefuran, Pyriproxyfen, Permethrin.
Dinitefuran, Pyriproxyfen, Permethrin.
Active Ingredients: Fipronil 9.80%, (S)-methoprene 8.80%.
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Fipronil, Permethrin, Pyriproxyfen.
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Active Ingredients: Dinotefuran 4.95%, Pyriproxyfen 0.44%, Permethrin 36.08% Other Ingredients: 58.53%
Active Ingredients : Fipronil , (S)-methoprene , Pyriproxyfen.
Kills or Treats           
Fleas, Mosquitoes, Ticks
Fleas, Mosquitoes, Ticks
Fleas, Mosquitoes, Ticks
Biting Flies, Chewing Lice, Flea Eggs, Flea Larvae, Fleas, Mosquitoes, Ticks
Biting Flies, Chewing Lice, Flea Eggs, Flea Larvae, Fleas, Mosquitoes, Ticks
Flea Eggs, Flea Larvae, Fleas, Ticks
Flea Eggs, Flea Larvae, Fleas, Ticks
Chewing Lice, Flea Eggs, Flea Larvae, Fleas, Ticks
Chewing Lice, Flea Eggs, Flea Larvae, Fleas, Ticks
Chewing Lice, Flea Eggs, Flea Larvae, Fleas, Ticks
Chewing Lice, Flea Eggs, Flea Larvae, Fleas, Ticks
Breed Size           

Questions & Answers

22 Customer Questions


Can I pause this ?


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.

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.

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.

4.4
Rated 4.4 out of 5 stars
3444 Ratings

Customers Mention

Chewy identifies key considerations with the help of artificial intelligence and our veterinarians.

Ease of Use

84% Positive

Effectiveness

83% Positive

Ingredients

82% Positive

Long-Term Benefits

84% Positive

1554 Customer Reviews



Always consult a veterinarian about your pet’s health needs. Customer reviews should not be used as medical advice.

Rated 1 out of 5 stars
By Ann-Bettina on Oct 15, 2025

Useless product

I switched to this topical flea medication from Nexgard chews because my senior pup has had many teeth removed and couldn’t get the shoes down. I’m so frustrated

I switched to this topical flea medication from Nexgard chews because my senior pup has had many teeth removed and couldn’t get the shoes down. I’m so frustrated because K9 Advantix i has proven to be absolutely useless. My poor animal is chewing himself raw from fleas daily and I am constantly picking a half a dozen fleas off of his body at any given time.. I’m upset because I had ordered this using auto ship and now have a huge supply of this useless product!


Rated 5 out of 5 stars
By Don on Oct 16, 2025

The product works as described in it’s description

We’re happy that our ‘Shorkie’ is tick/flea free. Noteworthy, though, is that the product produces skin irritation for a couple of days, an itching. From our Vet,

We’re happy that our ‘Shorkie’ is tick/flea free. Noteworthy, though, is that the product produces skin irritation for a couple of days, an itching. From our Vet, we’ve learned that is very common in many breeds. We’ve rated it ‘5’ as it performs as described.


Rated 5 out of 5 stars
By Natalie on Aug 11, 2025

ELIMINATES LIFE CYCLE BEATS PRESCRIPTION BRAVECTO

Lila had always been on K9 Advantix II since she was a puppy until the Palisades Fire happened. I took her into the vet who prescribed and administered Bravecto,

Lila had always been on K9 Advantix II since she was a puppy until the Palisades Fire happened. I took her into the vet who prescribed and administered Bravecto, a topical that supposedly works for 3 months. Lila kept itching etc. and i was convinced that the active ingredients were not as effective as K9 Advantix II which targets the life cycle of fleas, ticks, biting flies etc. by killing the eggs, larvae as well as the adult pests. I am happy that Lila is back on track with K9 Advantix II. I also purchased original K9 Advantix as well for a back up.


Rated 1 out of 5 stars
By Kimberly on Aug 2, 2025

Waste of money

I used Trifexis for years on my 2 pups but it became a struggle to get them to take it every month so I researched and found K9 Advantix. Reviews were great so I

I used Trifexis for years on my 2 pups but it became a struggle to get them to take it every month so I researched and found K9 Advantix. Reviews were great so I set up auto ship. This product is worthless, I have had to apply it every 3 weeks instead of the recommended 4 weeks due to fleas. I’m picking a minimum of 10 fleas off of them after their potty time outside which is about 6 times a day. My male pup scratches so bad after coming in that he’s licking himself raw. I have stopped my auto ship and now will try the Selesto collar. Hopefully it works better.


Rated 5 out of 5 stars
By Debbie on Oct 6, 2025

Always works!

I noticed a couple of fleas on Lilly so I ordered the K9 Advantix. After applying the medication, I didn’t see anymore fleas. I’ve tried other flea meds, but always

I noticed a couple of fleas on Lilly so I ordered the K9 Advantix. After applying the medication, I didn’t see anymore fleas. I’ve tried other flea meds, but always return to K9 Advantix.


Rated 1 out of 5 stars
By Bessie on Aug 17, 2025

Fleas

At first I thought impossible since I gave him medicine the first time but a flea was found during grooming. Now a 2nd time just looking at him n seen for my own

At first I thought impossible since I gave him medicine the first time but a flea was found during grooming. Now a 2nd time just looking at him n seen for my own eyes in my bed. I guess paying less doesn't mean nothing for me so I will go back to original which I never had any problems with more money but no problems. This product doesn't work for my dog.


Rated 1 out of 5 stars
By Katharine on Sep 20, 2025

never received

it shows a package was delivered to my front door. However, the picture of the package at the front door is not my front door so I not have the product that I

it shows a package was delivered to my front door. However, the picture of the package at the front door is not my front door so I not have the product that I ordered.


Rated 3 out of 5 stars
By Vicky on Oct 8, 2025

Product worked for a couple of weeks along with bug MD spray

Fleas are a big issue this year. Dogs run out in the the woods for a while then return to stay most of the days inside. 2 Jack Russell lots of energy.

Fleas are a big issue this year. Dogs run out in the the woods for a while then return to stay most of the days inside. 2 Jack Russell lots of energy.


Rated 4 out of 5 stars
By Terri on Aug 9, 2025

For the occasional hitchhiking flea

Oreo has been picking up a few fleas, presumably from his outdoor walks. This is a good product that has easy to apply instructions, no unpleasant odor, and seems

Oreo has been picking up a few fleas, presumably from his outdoor walks. This is a good product that has easy to apply instructions, no unpleasant odor, and seems to be doing the trick at keeping the critters off of Oreo. Have only used 1 dose so far but will continue with this product. As always, happily satisfied with Chewy


Rated 1 out of 5 stars
By Vance on Aug 19, 2025

The product does not work.!

How can you continue to sell a product that does not work and is a waste of money depending on people like me not to contactyou because I’m not stopping here. I’m

How can you continue to sell a product that does not work and is a waste of money depending on people like me not to contactyou because I’m not stopping here. I’m going online. I am sharing this experience and as far as I’m concerned, your product should be taken off market