K9 Advantix Flea, Tick & Mosquito Prevention for Medium Dogs, 11-20 lbs, 2-Monthly Treatments

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About This Item

Details

  • K9 Advantix for medium dogs is ideal for dogs ages seven weeks and older weighing 11–20 pounds.
  • Formulated to protect your pup from fleas, ticks, mosquitoes, biting flies, and lice for 30 days per treatment.
  • Works on contact to kill and repel fleas on dogs within 12 hours of application even without a bite.
  • This easy-to-apply topical treatment is fragrance-free and waterproof after 24 hours.
  • K9 Advantix offers fast relief—no prescription needed.

Ingredient Information

Instructions

K9 Advantix for Dogs

K9 Advantix, from the Advantage brand, prevents and treats fleas, ticks, mosquitoes, biting flies, and lice on dogs. It works through contact to kill fleas on dogs within 12 hours of initial application. Do not use on cats.

One Application Protects for 30 Days

This once-a-month topical flea and tick treatment is easy to apply, and the fragrance-free formula is waterproof after 24 hours of application. Plus, K9 Advantix is available without a prescription, so you don’t have to go to the vet to get it.

How It Works

K9 Advantix kills fleas through contact. It also kills and repels mosquitos and ticks, kills lice, and repels biting flies. Apply K9 Advantix to your dog once every 30 days according to the complete directions for use on the product label.

Find the Right Dose for Your Dog 

Your dog should be at least 7 weeks old to use K9 Advantix. It comes in four sizes, according to your dog's weight: Small Dog (4-10 lbs.), Medium Dog (11-20 lbs.), Large Dog (21-55 lbs.), and Extra-Large Dog (over 55 lbs.). Use as directed by label.

About Advantage

The Advantage family of products has what 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.

Shop Advantage

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Reviews
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4.3
Rated 4.3 out of 5 stars
349 Ratings
Terms & Conditions

Customers Mention

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

Ease of Use

71% Positive

Effectiveness

68% Positive

Ingredients

70% Positive

Long-Term Benefits

70% Positive

101 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 Lisa on Dec 15, 2025

Defective

It mustve been defective because it didnt work as it shouldve ive used this in the past on other furbabies and it worked great this time around it was horrible at

It mustve been defective because it didnt work as it shouldve ive used this in the past on other furbabies and it worked great this time around it was horrible at doing its job.

Rated 4 out of 5 stars
By Shelly on Nov 15, 2025

Works great

This flea medication works really good for my pets and the price is great. I will say I think it doesnt last the full month though, but maybe like up to 3ish weeks

This flea medication works really good for my pets and the price is great. I will say I think it doesnt last the full month though, but maybe like up to 3ish weeks for my pets but thats okay I just use it every month and keep up on it so its not an issue.

Rated 5 out of 5 stars
By Jackie on Dec 17, 2025

Love Chewy

Everything I order from chewy for my dog and cats arrives quickly, in excellent condition, always dependable!

Everything I order from chewy for my dog and cats arrives quickly, in excellent condition, always dependable!

Rated 1 out of 5 stars
By Esther on Oct 13, 2025

DO NOT PURCHASW

Terrible result. Toby got deathly sick and stopped eating and drinking. Took him to the vet and he said "this stuff is poison". Don't take a chance, you don't

Terrible result. Toby got deathly sick and stopped eating and drinking. Took him to the vet and he said "this stuff is poison". Don't take a chance, you don't know how your dog will respond to this very potent product.

Rated 4 out of 5 stars
By Sheri on Sep 23, 2025
Top 500 Contributor

Value of price and easy application

I give this flea treatment a 31/2 stars because it took longer than the package statement as length of time to minimize the fleas on my pup. I say minimize because

I give this flea treatment a 31/2 stars because it took longer than the package statement as length of time to minimize the fleas on my pup. I say minimize because the amount of fleas has been reduced but not killed or prevent the fleas completely.

Rated 4 out of 5 stars
By Mallory on Sep 10, 2025

I am unsure still if it worked.

I think it help but my pups still scratching it; he’s a long hair Chihuahua. Could be that his skin is just dry maybe but his coat looks slimy so I don’t know why

I think it help but my pups still scratching it; he’s a long hair Chihuahua. Could be that his skin is just dry maybe but his coat looks slimy so I don’t know why he’s still biting after the medicine. So I gave a 4 star.

Rated 4 out of 5 stars
By Martin on Oct 22, 2025

Trusted Name

Worked well for my dane and for the little 20lb mix too. Ordered both sizes. Easy to apply. No trouble

Worked well for my dane and for the little 20lb mix too. Ordered both sizes. Easy to apply. No trouble

Rated 5 out of 5 stars
By Holly on Oct 10, 2025

No fleas seen since using

I used this on 3 dogs all summer. My dogs haven't had any fleas or ticks since using. Reasonably priced. No scent.

I used this on 3 dogs all summer. My dogs haven't had any fleas or ticks since using. Reasonably priced. No scent.

Rated 1 out of 5 stars
By Lance on Sep 26, 2025

Doesn't work for mosquitoes

In description it includes mosquitoes. Two days after applying I saw 4 land on him. Some right over application site.

In description it includes mosquitoes. Two days after applying I saw 4 land on him. Some right over application site.

Rated 5 out of 5 stars
By Barbara on Aug 8, 2025

Your over the top customer service

We had to lay our precious pup to rest this week and your customer service ladies were sooo supportive. Will join you again when I’m ready to rescue another pup

We had to lay our precious pup to rest this week and your customer service ladies were sooo supportive. Will join you again when I’m ready to rescue another pup. Your company values are outstanding.