K9 Advantix II Flea & Tick Spot Treatment for Dogs, over 55 lbs, 6 Doses (6-mos. supply)

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About This Item

Details

  • Helps to protect dogs over 55 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.

Shop K9 Advantix II

Questions & Answers

26 Customer Questions


Where is the manufacturer date on the box?

Answer by CoraMay 09, 2023
On back in bottom left cornergood for 18 months from that date

Can this product be used on pregnant dogs?

Answer by ChewyMay 21, 2018
K9 Advantix II is suitable for use with a pregnant or lactating dog.

Where is this made and how effective is this for tics

Answer by ChewyMay 28, 2018
This is made in Germany.

Can I use both this along with the collar flea preventer?

Answer by ChewyAug 15, 2018
We encourage speaking with your Veterinarian before combining supplements, for the safest opinion.

4.5
Rated 4.5 out of 5 stars
5828 Ratings

Customers Mention

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

Ease of Use

84% Positive

Effectiveness

82% Positive

Ingredients

80% Positive

Long-Term Benefits

82% Positive

2746 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 Nancy on Dec 28, 2025

The lousy delivery system.

My package was just thrown in my driveway and when I received the message it was delivered I went out to get it. It says he dropped it at my front door which is

My package was just thrown in my driveway and when I received the message it was delivered I went out to get it. It says he dropped it at my front door which is not what he did. I was having another delivery by a different company and had I not seen the package they would have run over it. Is this the way your drivers deliver packages? If so, maybe I should shop elsewhere. I'm including a picture and you tell me if that is my front door or the middle of my driveway.


Rated 5 out of 5 stars
By Kathy on Nov 5, 2025

Fast shipping

I switched to K9 Advantix II because it is affordable and it works. I groom dogs out of my home for friends and family, and sometimes they come to me with fleas

I switched to K9 Advantix II because it is affordable and it works. I groom dogs out of my home for friends and family, and sometimes they come to me with fleas. K9 Advantix II works quickly to repel fleas and ticks. With the uptick in Lyme disease in my area, among other tick borne illnesses, this is something that they can use year round


Rated 5 out of 5 stars
By JOANNE on Jan 14, 2026

It’s working!

I actually thought I was ordering Advantage for large dogs but bought this one instead. No complaints though, as it seems to be working.

I actually thought I was ordering Advantage for large dogs but bought this one instead. No complaints though, as it seems to be working.


Rated 5 out of 5 stars
By 2Shepherds on Oct 28, 2025
Top 10 Contributor

The best flea and tick product for our shepherd

Had been using a less costly brand for a long time, but switched to K9 Advantix II when that previous brand stopped working. Wow, what a difference! It's true you

Had been using a less costly brand for a long time, but switched to K9 Advantix II when that previous brand stopped working. Wow, what a difference! It's true you get what you pay for, as the Advantix started working immediately with no bad reaction, and her scratching stopped, and still no fleas seen on her going into week three. This will be our go to from now on.


Rated 3 out of 5 stars
By Susan on Nov 4, 2025

Ok Topical Flea and tick treatment

After trying Bravecto which caused diarrhea in both of my dogs, I have reverted to using Advantix. It is easy to put on them and they don't seem to mind it (no obvious

After trying Bravecto which caused diarrhea in both of my dogs, I have reverted to using Advantix. It is easy to put on them and they don't seem to mind it (no obvious odor). It does leave discoloration on the white fur though but have not seen any fleas or ticks on them this Summer.


Rated 1 out of 5 stars
By Jenny on Dec 13, 2025

Does not work

After applying this on my dog per the instructions, it wasn't long after that a tick soon found his way onto my dog as well. It should be called "tick attractor

After applying this on my dog per the instructions, it wasn't long after that a tick soon found his way onto my dog as well. It should be called "tick attractor"


Rated 1 out of 5 stars
By Breezi on Nov 17, 2025

I do not recommend!

Terrible skin reaction, I was trying to keep my girl from getting fleas or ticks..... Now she's crazy scratching because I applied this to her. I feel like a horrible

Terrible skin reaction, I was trying to keep my girl from getting fleas or ticks..... Now she's crazy scratching because I applied this to her. I feel like a horrible pet parent & now I have 3 doses to throw away.


Rated 5 out of 5 stars
By Mary on Dec 9, 2025

Great customer service

Just had a delightful time with the customer service agent she went above and beyond to help get what I needed! She is the best part of Chewy

Just had a delightful time with the customer service agent she went above and beyond to help get what I needed! She is the best part of Chewy


Rated 5 out of 5 stars
By Joanne on Dec 27, 2025

Quick Delivery

I wanted to get meds in advance for next spring. Delivery was with in the 3 days just as promised. Love Chewy!!!

I wanted to get meds in advance for next spring. Delivery was with in the 3 days just as promised. Love Chewy!!!


Rated 5 out of 5 stars
By Ashley on Dec 10, 2025

Flea Meds

My dog was covered in fleas and itching all the time. The flea meds helped and within a day they were mostly gone and they quit itching.

My dog was covered in fleas and itching all the time. The flea meds helped and within a day they were mostly gone and they quit itching.