K9 Advantix II Flea & Tick Spot Treatment for Dogs, 21-55 lbs
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Help protect your precious pooch from parasitic pests and the potentially harmful diseases they can transmit with K9 Advantix II Flea & Tick Treatment for Large Dogs. This broad-spectrum, veterinarian-recommended treatment is specifically formulated to repel and kill fleas, ticks and mosquitoes on contact with no painful biting required. It further kills all life stages of fleas to prevent re-infestation, and even kills lice while also repelling biting flies. The waterproof formula for puppies and dogs 7 weeks or older and weighing between 21 and 55 pounds continues working for up to four weeks, even after bathing or swimming.
Key Benefits- Broad-spectrum, veterinarian-recommended treatment repels and kills fleas, ticks and mosquitoes on dogs 7 weeks or older and weighing 21-55 pounds.
- Begins working within 12 hours and kills pests on contact.
- Kills all life stages of fleas to prevent re-infestation; also kills lice and even repels biting flies.
- Waterproof formula continues working for up to four weeks, even after bathing or swimming.
- Convenient, monthly topical application contains imidacloprid, permethrin and pyriproxyfen; available in packs of 2, 4 or 6 treatments.
USE ONLY ON DOGS AND PUPPIES 7 WEEKS OF AGE AND OLDER AND WEIGHING 21 - 55 LBS. DO NOT USE ON CATS. Do not get this product in dog's eyes or mouth. As with any product, consult your veterinarian before using this product on debilitated, aged, pregnant or nursing animals. Individual sensitivities, while rate, may occur after using ANY pesticide product on dogs. If signs persist, or become severe, consult a veterinarian immediately. If your animal is on medication, consult your veterinarian before using this or any other product. Keep out of reach of children.
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Item Number74405
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UsagePrevention
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BrandBayer
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LifestageAdult, Puppy, Senior
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Breed SizeSmall Breeds, Medium Breeds
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Product FormSolution
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Health ConditionFleas, Ticks
Active Ingredients: Imidacloprid 8.80%, Permethrin 44.00%, Pyriproxyfen 0.44%
How to open:
- Be sure tube is at bottom of pouch.
- Using scissors, cut the pouch across the top and remove tube.
How to apply:
- Use only on dogs.
- Remove applicator tube from the package. Use scissors and peel down foil.
- Hold applicator tube in an upright position. Pull cap off 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 empty tube.
- In cases of severe pest infestations, retreatment is allowable earlier than 4 weeks. Do not retreat more often than once every 7 days. After pest control is attained, return to a monthly retreatment schedule.
Dog Weight | K9 Advantix II | Volume |
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Under 10 lbs | Small Dog | 0.4 mL tube |
11 - 20 lbs | Medium Dog | 1.0 mL tube |
21 - 55 lbs | Large Dog | 2.5 mL tube |
Over 55 lbs | Extra Large Dog | 4.0 mL tube |
Where is this product sourced from?
We source all our products from manufacturer approved distributors or directly from the manufacturers. Chewy takes pride in ensuring that our furry friends’ wellbeing is always our top priority. We have worked hard to partner with all of the manufactures to deliver 100% authentic products
How long after using another topical product do I need to wait before applying K9 Advantix II?
Please consult your dog’s veterinarian for their recommendation. Do not use K9 Advantix II on cats.
How long does K9 Advantix II last?
A single application of K9 Advantix II keeps working for a month. Do not use K9 Advantix II on cats.
Can I bathe my dog after applying K9 Advantix II?
Yes! However, we suggest bathing your dog before applying K9 Advantix II. Just make sure your dog is thoroughly towel dried. If you choose to bathe your dog in between treatments, we recommend use of a general grooming shampoo for pets. Do not use K9 Advantix II on cats.
Can I apply K9 Advantix II more than once a month?
A single application of K9 Advantix II remains effective for four weeks. However, if the dog has a severe infestation, retreatment within a month may be necessary. Do not retreat more than once every seven days not to exceed weekly treatments. After flea control is attained, return to a monthly treatment schedule. Do not use K9 Advantix II on cats.
Why do I still see fleas after using K9 Advantix II?
Although K9 Advantix II kills fleas on your dog, there may still be fleas in your dog's environment that have since jumped on after treatment. Luckily, with K9 Advantix II, new fleas are killed within 2 hours with protection against further infestation for at least 4 weeks. As fleas die they are no longer able to stay hidden against your dog's skin, and therefore you may also be seeing dying fleas coming to the surface of your dog's fur coat. Do not use K9 Advantix II on cats.
How long does it take for K9 Advantix II to work on fleas?
K9 Advantix II kills fleas within 12 hours. New fleas that jump on the dog from the surroundings, such as grass, carpet and pet bedding, are killed within 2 hours with protection against further infestation for at least 4 weeks. Do not use K9 Advantix II on cats.
Can my dog go swimming after using K9 Advantix II?
Yes! Your dog is free to take a dip after K9 Advantix II has been on for 24 hours. More frequent swimming may keep the product from working for the full 30 days. Do not use K9 Advantix II on cats.
How does K9 Advantix II work?
Not all products work the same way: K9 Advantix II is applied to the pet's skin, spreading the active ingredients over your dog's body to kill fleas, ticks and mosquitoes through contact. No biting required! Do not use K9 Advantix II on cats.

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

K9 Advantix II Flea & Tick Treatment for Small Dogs
4-10 pounds

K9 Advantix II Flea & Tick Treatment for Medium Dogs
11-20 pounds

K9 Advantix II Flea & Tick Treatment for Large Dogs
21-55 pounds

K9 Advantix II Flea & Tick Treatment for Extra Large Dogs
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.

Customer Reviews
90% Recommend
90% of reviewersrecommend this product
You've Already Reviewed This Item
1091 Reviews
Showing 1-10 of 1091 Reviews
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We use K9 Advantix II monthly
By John on Dec 29, 2020
We live in South Florida which means there are a lot of mosquitos. Our Veterinarian explained K9 Advantix II kills them before they can bite. Most dog owners know mosquitos carry Heart Worms so if we protect them from the source and maintain internal protection and reduce the chance of loosing one of our special pets. Midnight is a trained Service Dog, cross trained Therapy dog and loves to show in Obedience competitions.
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Works great
By BJBK9 on Jan 9, 2021
I have three dachshunds and a brittany that are using K9 Advantix II. In the past I have had allergy to flea and tick treatments but I have been using K9 Advantix II on them for 7 months and no problems. It works well for all of them.
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First time buyer.
By Jolly on Jan 19, 2021
Had to find an alternative to seresto collars, they had become ineffective on my dog. Advantix was a great choice! (Recommended by Chewy staff) going on week three and no fleas or irritations on my Libby.
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Flea Stuff
By Maggiesmom on Feb 24, 2021
Easy to order and apply on my dog. Would reorder same stuff in next 6 months. Delivery was also very easy.
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No more fleas
By Susan on Feb 7, 2021
Easy to apply and works into the coat quickly. Extremely effective on my dog who is constantly rolling in the grass.
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Don’t buy this!
By Andrea on Nov 2, 2020
I live in the South, so fleas and ticks are numerous here. I used this on my dog for about one year. The first six months, the first box, was great! No problems! However, the second box didn’t work. We found ticks on my dog. I don’t know if they changed the ingredients in this, but I don’t recommend!
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Best By Far
By DogMom on Oct 23, 2020
My former dog was constantly invested during flea season here in SoCal. Everyone said the famous brand was the best around but it did absolutely nothing. We rescued our two new pups during summer and they immediately attracted fleas. Despite vet recommendations I don’t like the idea of my dogs taking chewable flea meds that stay in their blood stream. Decided to try K9 Advantix II and was surprised it actually worked. I still find fleas in their fur, but they’re all dead. I notice mosquitos landing on the dogs, but I don’t know if this has deterred them from biting.
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Flea drops
By Buttun4 on Jan 8, 2021
Highly recommended The advantix 2 flea and tick drops Works great on my dogs monthly And comes for different sizes
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Been using for 6 years
By Sarah on Feb 9, 2021
Never had any issues with this product and Chewy makes it easy to receive it!
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Bad choice for my Siberian Husky
By RVAHusky on Sep 27, 2020
Decided to try Advantix II instead of our usual topical product (the one that has been around forever). This product made my Husky very itchy and very restless. The first day she would not settle down and was visibly agitated. And she was itching and scratching at her back for at least a week afterwards. I am going to go back to our former treatment product as it had no adverse effect.