K9 ADVANTIX II Flea & Tick Spot Treatment for Dogs, 21-55 lbs, 6 Doses (6-mos. supply) - Chewy.com

K9 Advantix II Flea & Tick Spot Treatment for Dogs, 21-55 lbs

By K9 Advantix II
Rated 4.2223 out of 5 stars

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About This Item


  • Helps to protect dogs weighing 21 to 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.

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Play Video: Learn More About K9 Advantix II From Our Team of Experts
Learn More About K9 Advantix II From Our Team of Experts

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.
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Questions & Answers

30 Customer Questions

Do fleas have to bite my dog in order for the medication to work?
Answer by ChewyFeb 16, 2023
This preventive kills through contact and no biting is necessary for it to be effective.

Can I use K9 Advantix II on my indoor dogs if I have indoor cats?
Answer by ChewyOct 20, 2022
This flea and tick treatment should not be ingested. Cats should not come into contact with this product, so they should be placed in a different environment while this treatment is being applied.

How do you apply the topical treatment? Is it messy?
Answer by ChewySep 11, 2017
To apply, remove applicator tube from the package. Use scissors and peel down foil. Hold applicator tube in an upright position and pull the cap off the tube. Turn the cap around and place other end of cap back on tube. Twist cap to break seal, then remove cap from tube. The dog should be standing for easy application. The entire contents of the K9 Advantix II tube should be applied evenly on the top of the back from the shoulder to the base of the tail. At each spot, part the hair until the skin is visible. Place the tip of the tube on the skin and gently squeeze to expel a portion of the solution on the skin. Do not apply an excessive amount of solution at any one spot that could cause some of the solution to run off the side of the dog. Discard the empty tube.

I have an inside dog & was wondering if I treated my dog while he stayed inside if the fleas would jump off him & make their home in my house??
Answer by ChewyNov 21, 2017
This treatment kills pests on contact so, they won't invade your home.

ReviewsWrite a Review

Rated 4.2223 out of 5 stars
1336 Ratings
Would recommend to a friend

1336 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 carolinacanines on May 24, 2023

ineffective against ticks

I hate ticks! Living in the country means they’re inevitable. I purchased two boxes of this for my large dogs and they still have living ticks! Imagine my dismay when I see these nasty demons on my dogs after I applied this medication. I followed the directions and unfortunately this product is completely ineffective against the disgusting blood suckers. I’m now out quite a bit of money for the two boxes and my dogs are still not protected. I’m now looking for another option.

Rated 1 out of 5 stars
By Mel on May 3, 2023

Waste of money!

I have two boston Terriers, I called and the representative said it was the best, I think she meant the worst. It did not work at all! I would like to send the other two back And get some kind of refund it was a waste of sixty two dollars. Not happy at all, We are big fans at chewy but not lately. When our dog food was delivered they put it at the mailbox down our drive way. Called and reported it They saw the picture and never got to call back. We are thinking about canceling chewy.

Rated 5 out of 5 stars
By dinaB on May 21, 2023

It works with a caveat

I want to say I use this on my dogs because i live in a wooded area by a creek, ticks are a major issue here. We get fleas also and this product works great, its a contact killer that kills when the pests get on them, they dont have to take a bite to die. This product can cause a tingly sensation on the skin which some sensitive dogs, one of mine included, can look like an allergic reaction. The sensation will go away once the product dries. As far as i know there are only 3 products that kill on contact, this, vectra and seresto collar. The pills they have to take a bite in order to die there is no repellant in the pills. I choose this because my area is loaded with ticks fleas mosquitoes, and this works for us. Plus if my dog has a true allergy reaction some dawn dish soap and it removes the product, unlike a pill that is internal. Imo this is a far safer option than most, do not let cats near it though. It is deadly to cats. When applying do not put it all in one spot, start between the shoulder blades put a little there then in 3 more small spots down the back. Never overload one area with the product. Small spots also help reduce any tingly sensation the dog may get. Dont let the dog rub it off for about 2 hours after take him for a walk or play with him. Dont let other dogs mouth each other till its dry, dont let kids pet him till dry. Once dry you can brush him out and never know the stuff was there. Wait 48 hours after a bath to apply and makes sure he is dry, I dont let them get wet for 48 hours after also. after that its pretty well set up. For the first 12 to 18 hours if your dog was infested you will see a lot of activity as the fleas and ticks go hyper trying to escape the product, that is normal. What isnt normal is skin burns or scabbing where you put the product, if you dump toomuch in one spot it can cause it, as well as a true reaction to the ingredient in some dogs. Any lethargy drooling staggering can mean your dog ingested some by licking it off, or is having a true allergy reaction...wash them with dawn twice and call your vet. I dont put it where they can reach it, and i observe them until its dry. I still choose this over an internal pesticide, you cant remove an internal chemical.

Rated 1 out of 5 stars
By keki on May 28, 2023

burned my dog’s skin

I used advantix for year for my dog. In recent months, I noticed my dog always have scars on his back. and it’s always found the scar on the spots after 2-3days afterI used the topical. Not too sure what happened, but I will stop using it and maybe use some flea collar instead.

Rated 2 out of 5 stars
By EverybodysMomma on May 22, 2023

Works so so

I have seen a decrease in the number of ticks on my dog but not completely gone. I have not seen any fleas but she didn't have any prior to application. I'm planning on trying a different product after this one wears off.

Rated 5 out of 5 stars
By Kathy on Apr 10, 2023

100% recommended

been using this product for years. works 3 weeks to the day. if you go over those 3 weeks in the summer when fleas are everywhere outside, simply apply and in literally a couple of hours ALL fleas have disappeared! chewy accidentally shipped me the ADVANTAGE and I wouldn't even use it. waited on my k9 advantix to arrive from a new order.

Rated 2 out of 5 stars
By Karyoly53 on Mar 23, 2023

Not strong enough

I have bought 2 kits for my dogs depending on their weight and still have fleas. Spending more money for sprays, shampoos to keep them free of fleas at least for a couple of weeks. The pill works much better but they give me a hard time to take. This item is very expensive for their effectiveness. Would not recommend to spend your money.

Rated 5 out of 5 stars
By DMH on Apr 30, 2023

FAST Delivery

My order arrived quickly so my pets get their treatment before being boarded. K9 Advantix Ii keep my pets safe from fleas & ticks. I have been using K9 Advantix Ii for over 20 years.

Rated 1 out of 5 stars
By KA26 on May 15, 2023


I used this on my 5 year old golden doodle, after always using the pill from the vet, and made her break out in scabs and was SUPER uncomfortable.

Rated 5 out of 5 stars
By Sandi on Apr 5, 2023


This is a great product and the only one I can use on my fur babie's my boy get's a reaction to the other stuff..I use half of the dose on each of my dog's at the first sign of flea's and works very well and fast delivery from chewy 🙂