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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.

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Questions & Answers

29 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

What is the difference between this product and the other Advantix (not II)?

Answer by Fleas • May 19, 2026
K9 Advantix II also targets eggs and larvae. Advantix 1 does not.

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.
Reviews
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4.5
Rated 4.5 out of 5 stars
6533 Ratings
Terms & Conditions

Customers Mention

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

Ease of Use

84% Positive

Effectiveness

83% Positive

Ingredients

80% Positive

Long-Term Benefits

83% Positive

2945 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
Verified Purchase
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
Verified Purchase
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 1 out of 5 stars
Verified Purchase
By Rosie on Aug 1, 2025

No receipt of Fle meds

This box was torn open. The boxes of Fle meds were shredded and all but a few packets received as they fell through the hole in the large box with other items

This box was torn open. The boxes of Fle meds were shredded and all but a few packets received as they fell through the hole in the large box with other items. Plus one bottle of flea spray came open and made one box of Casters come apart as it was soaked. Luckily, the bones are wrapped. The large box containing all items was too large causing the inners to bang and roll around causing this damage. The large box should have had inner packaging that would have stabilized items from rolling around. I have only a mixture of Advantage packets; maybe 5-6 packets total. One box of Casters was soaked from the bottle of flea spray and came apart but contained all the wet food. Did any of this liquid flea spray seep into the food? I don't know if it'll safe to feed my dog. I complained once before about how items are packed and I ordered 3 separate times so they wouldn't have damage. However, the 3 orders were combined anyway. I tried to avoid damage from past experience of having damage. My good intentions didn't avoid combining all items. I lost half a bottle of spray. I lost most of Advantage Flea meds. Not sure of one box of Casters. Happy and satisfied I AM NOT. B thinking of ordering from another smaller company that packs more carefully and not by a robot that has NO brain. I'm not sure you should have one star. I want compensation for this mess received.

Rated 1 out of 5 stars
Verified Purchase
By Cindy on Feb 26, 2025

Flea control not working

I have been using the same flea control meds Advantix II for years. It has always worked great with no problems until now. I don’t know if I somehow got a bad box

I have been using the same flea control meds Advantix II for years. It has always worked great with no problems until now. I don’t know if I somehow got a bad box or what but my dog has had fleas even a few days after administering it. I thought maybe I did something wrong so before I administered rge 2nd vial I gave my 50lb Cur an hour bath with a scrubbing, I washed at least 30 fleas off him which I’ve never seen more than a few in baths before. Then I let him dry and put the meds on. The next night I was checking him and found multiple fleas again. That was 3 days ago. Today a flea jumped on my husband while he was loving on Boog(our Cur dog). So I checked him again and I pulled more fleas off him. Something is not right with this batch from Chewy.

Rated 1 out of 5 stars
Verified Purchase
By Susan on May 23, 2026

Ease of use few side effects or so I thought

We used the topical flea and tick products before on our collies and it was fine. We used it on our current dog and it resulted in him going after the spot it was

We used the topical flea and tick products before on our collies and it was fine. We used it on our current dog and it resulted in him going after the spot it was applied to. Him constantly biting it caused a hotspot. We'll be using flea collar going forward. We also bought the vetericyn spray you sell but that didn't have any effect. Ended up at the vet for oral antibiotics and Betagen topical spray along with the cone of shame and a $200 vet bill. So no I wouldn't recommend k9 advantix.

Rated 5 out of 5 stars
Verified Purchase
By Linda on Jun 25, 2025

Quick delivery and ease of ordering

I love Chewy! The prices are good and it only takes a few minutes to complete my order. I've used Chewy many years and only once was the order not correct. I called

I love Chewy! The prices are good and it only takes a few minutes to complete my order. I've used Chewy many years and only once was the order not correct. I called them and offered to send it back for the replacement. They said no, donate it to your local shelter and they overnighted my correct order! This company is fantastic. Thank you Chewy!

Rated 5 out of 5 stars
Verified Purchase
By Shayne on Aug 24, 2018

Amazing stuff!!

Ok so I have 27 rescued dogs. Yes it’s a house full, they are all spoiled and loved but the one thing I struggled with was fleas. I’ve tried all brands and homemade

Ok so I have 27 rescued dogs. Yes it’s a house full, they are all spoiled and loved but the one thing I struggled with was fleas. I’ve tried all brands and homemade solutions you can think of. None really helped for long term. So I decided to try this product and I had to treat half the dogs at a time but just with treating 12 dogs!!!! My flea infestation dropped significantly. But the time I treated the rest of them I have seen MAYBE one or two fleas. I will swear by this that it works for me and my dogs are no longer itchy or having bald spots and I will continue to buy this product

Rated 5 out of 5 stars
Verified Purchase
By 3doglover on Mar 15, 2014

This product has the most extensive coverage.

There are several flea and tick topical preventions for dogs with lower prices available. But pets are victims of other annoying pests that will make their lives

There are several flea and tick topical preventions for dogs with lower prices available. But pets are victims of other annoying pests that will make their lives miserable. Also these lower priced brands may only kill the adult fleas. K9 Advantix II repels and kills all life stages of fleas for a month. In addition to killing all the most common types of ticks, this product kills chewing lice and blood sucking flies and mosquitoes as will. I have used this brand over 10 years. My only regret is that K9 Advantix II is not available for humans--it would be so wonderful to squeeze the tube on our skin and get 4 weeks protection from those flying pests!

Rated 5 out of 5 stars
By Matthew on Nov 18, 2017

Great product so far

Are cheap brand we have bought for years failed us.Both my 100 lbs dogs got fleas. So after 2 weeks of flea baths we got them under control. For the application

Are cheap brand we have bought for years failed us.Both my 100 lbs dogs got fleas. So after 2 weeks of flea baths we got them under control. For the application process unlike are old brand the twist cap has a hole to open the top of the tube up. The tip has a cup on it so applying it to the skin and slight moving it in a circle insures skin contact. Then a light squeeze a controllable amount comes out. I love this design. For how it works. I can not say yet. Flea and tick season has passed but we treat year round. I will update next spring when the darn pest return..but based off reviews and my vet this is suppose to be a great product. Fyi the instructions read to apply 4 small areas from neck and down. Different from what chewy said in the question column.

Rated 5 out of 5 stars
Verified Purchase
By Rottiesmum on Oct 23, 2021

Has worked great for 8 years!

We have two Rotties and have been using this ever since they had a weird reaction to Nexguard when they were pups. We’ve adjusted the dose along the way, always

We have two Rotties and have been using this ever since they had a weird reaction to Nexguard when they were pups. We’ve adjusted the dose along the way, always give them a bath the day we are going to dose and we put it on right before bed and crate them to keep them from licking / accidentally getting the medicine on furniture. It’s usually absorbed in by next evening and they are able to sleep back in their beds w/ us in our room. They don’t like to be two feet from us or one another but are used to being crated when needed.