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

Skip image gallery
Slide 1 of 9

$55.99 First Time Autoship Price
this order
Save 30% today when you set up Autoship. 
$75.99 Autoship Price
(-5%) future orders
  • Keep saving 5% on every order
  • Get deliveries on your schedule
  • Skip, change, or cancel anytime
$79.99 Chewy Price
($13.34 /ea)
Promo, Buy select cat food, get 30% off Select Flea and Tick item with code FLEA30
Promo, New Customers Only: Spend $49+, Get $20 eGift Card + Free Shipping with code: WELCOME
In Stock
FREE 1-3 day delivery
Free 365-day returns

No interest if paid in full in 6 months on PayPal purchases of $149+. .

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

Frequently bought together

Questions & Answers

26 Customer Questions

Where is the manufacturer date on the box?

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

Can this product be used on pregnant dogs?

Answer by Chewy • May 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 Chewy • May 28, 2018
This is made in Germany.

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

Answer by Chewy • Aug 15, 2018
We encourage speaking with your Veterinarian before combining supplements, for the safest opinion.
Reviews
Write a Review
4.5
Rated 4.5 out of 5 stars
6086 Ratings
Terms & Conditions

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

2816 Customer Reviews

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

Rated 5 out of 5 stars
By Victoria on Mar 30, 2026

The itching stopped

Our boy Winston loves catching rabbits. However, every time he catches one he ends up with mites or fleas all over his face and ears. We purchased K9 Advantix and

Our boy Winston loves catching rabbits. However, every time he catches one he ends up with mites or fleas all over his face and ears. We purchased K9 Advantix and applied it to him once it arrived. The next day the itching was still there but not as much, and by day 4 he was not itching at all. I feel the product worked instantly and he was just itching old bites. He’s been fine now, itch free for about 2 weeks. I have already set up an auto ship for this product.

Rated 5 out of 5 stars
By Rebecca on Mar 14, 2026

Terrific flea treatment maintenance

I bought this for my dog when we got a flea infestation from me bringing a newborn feral cat inside the house. I used two other types of monthly flea treatments,

I bought this for my dog when we got a flea infestation from me bringing a newborn feral cat inside the house. I used two other types of monthly flea treatments, which Chewy refunded my money for, carpet and spray treatments and it still didn’t get rid of them. I’ve been putting the K9 Advantix on her for 6-7 months now and I’m happy to report that she, and the house, are flea free now!! It took about 3 monthly doses before they were finally all gone. I guess it just had to get through all of the flea life cycles to get them all killed. This is definitely a great product to try out on your pet. Buy a 6 month supply and see what happens.

Rated 5 out of 5 stars
By Patti on Apr 2, 2026

GREAT price on 1st shipment of flea and tick treatment!

Since I need 6 doses every 6 months for my white German Shepherd, it is so EASY to depend on Chewy to ship it 2x/ year. And giving me a significant discount with

Since I need 6 doses every 6 months for my white German Shepherd, it is so EASY to depend on Chewy to ship it 2x/ year. And giving me a significant discount with the 1st shipment was frosting on the cake! What a great company - they were so fast with shipping. No hassle and lots of money and time saved. Thanks, Chewy!

Rated 4 out of 5 stars
By Barbara on Apr 2, 2026

Flea and tick

Works well had no issues with it no side effects with it. I have found no ticks or fleas. It gets four stars because I don’t like having to put this stuff on my

Works well had no issues with it no side effects with it. I have found no ticks or fleas. It gets four stars because I don’t like having to put this stuff on my dogs. And that goes for any flea stuff. I wish there was a more natural one that works better, but there is not. I have tried them all.

Rated 5 out of 5 stars
By Francis on Apr 1, 2026

Very pleased with this product

K9 Advantix II work very well on our 70 lbs. female dog. She will roam around our property and will get in the pasture at times, and we don't see any flea and sometimes

K9 Advantix II work very well on our 70 lbs. female dog. She will roam around our property and will get in the pasture at times, and we don't see any flea and sometimes I may find a tick on her, but I check her all the time. We are faithful in putting this flea medicine on her every month.

Rated 5 out of 5 stars
By Jennifer on Mar 17, 2026

Keep them fleas and ticks at bay

We love this product, ever since it first came out. As a veterinary nurse, we knew about Bauer, which were one of our favorite pharmaceutical companies. And this

We love this product, ever since it first came out. As a veterinary nurse, we knew about Bauer, which were one of our favorite pharmaceutical companies. And this product has been fantastic. Would highly recommend it, and put it on your dogs before you go to bed, and all dry and ready for the next day. Keeping those fleas and ticks at bay, all day everyday.

Rated 5 out of 5 stars
By Katie on Mar 12, 2026

The only stuff I will use on my animals

Always works so well. I use a tube between 2 full grown dogs and don't have to do it again for atleast 3 months. That's with them swimming and getting baths and

Always works so well. I use a tube between 2 full grown dogs and don't have to do it again for atleast 3 months. That's with them swimming and getting baths and all that good stuff. I have always preferred this over their competitors.

Rated 2 out of 5 stars
By JB on Mar 19, 2026

Damaged package

Upon receiving this item, it was smashed in the bottom of the box, with two tubes totally missing! I did use the remaining tubes but honestly, it did not work for

Upon receiving this item, it was smashed in the bottom of the box, with two tubes totally missing! I did use the remaining tubes but honestly, it did not work for us.

Rated 2 out of 5 stars
By Kelly on Feb 6, 2026

Pup is allergic to this

This product might be good for other folks, however my pup is extremely allergic to it. I tried it two different times. The first time my pups face swelled up and

This product might be good for other folks, however my pup is extremely allergic to it. I tried it two different times. The first time my pups face swelled up and the second time his face swelled and he threw up within 5 minutes of putting it on. I will be trying another brand.

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.