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K9 Advantix II Large Dogs 21-55 lbs Flea & Tick Treatment – 6 Doses

K9 Advantix II Large Dogs 21-55 lbs Flea & Tick Treatment – 6 Doses

Regular price $55.40
Regular price Sale price $55.40
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Shipping & Returns

Free USA Shipping on Orders Over $120

We ship all US domestic orders within 1-3 business days

Returns & Refunds Policy

30-Day Return Policy

We offer a 30-day return policy from the date of delivery.

To qualify for a return:


  • The item must be unused

  • The item must be in original packaging

  • Proof of purchase is required

Non-Returnable Items

The following items cannot be returned:


  • Opened pet food or treats

  • Personalized products

  • Clearance or final sale items

  • Hygiene-related pet products

Damaged or Incorrect Items

If you receive a damaged or incorrect product:


  1. Contact us within 72 hours of delivery

  2. Provide photos of the product and packaging

  3. We will arrange a replacement or full refund

Return Shipping


  • If the return is due to our error (damaged or incorrect item), we cover return shipping

  • If the return is due to customer preference, the customer pays return shipping

Refund Processing

Once we receive and inspect the returned item:


  • Refunds will be issued to the original payment method

  • Processing time: 5–10 business days
View full product details

Keeping your dog protected from fleas and ticks is important for their comfort and overall health. K9 Advantix II for Large Dogs is specially made for dogs weighing between 21–55 lbs, offering reliable monthly protection against fleas, ticks, mosquitoes, lice, and biting flies.

This easy-to-use topical treatment works quickly to kill fleas and repel pests before they bite. Whether your dog enjoys daily walks, outdoor play, or spending time in the yard, K9 Advantix II helps keep them protected throughout the month. The waterproof formula continues working even after bathing or swimming once fully absorbed.

Unlike ordinary flea treatments, K9 Advantix II not only kills parasites but also helps stop them from bothering your dog in the first place. With regular monthly use, it helps reduce flea infestations and supports a healthier environment for your pet and home.

Key Features

  • Fast-acting flea and tick protection
  • Repels fleas, ticks, and mosquitoes before they bite
  • Protects for up to 30 days
  • Waterproof formula after 24 hours
  • Easy monthly topical application
  • Suitable for dogs weighing 21–55 lbs
  • Helps control flea infestations and irritation

Why Pet Owners Choose K9 Advantix II

Many pet owners trust K9 Advantix II because it provides strong, long-lasting protection without complicated treatments. It is simple to apply and works well for active dogs that spend time outdoors. The formula starts working quickly, helping your dog stay comfortable and protected from harmful pests year-round.

How to Use

Apply the full contents of the tube directly to your dog’s skin between the shoulder blades. Use once every 30 days for continuous protection. Always read the label instructions carefully before use.

Frequently Asked Questions

1-Is K9 Advantix II safe for large dogs?

Yes, K9 Advantix II is designed for dogs weighing between 21–55 lbs and puppies older than 7 weeks.

2-How long does K9 Advantix II last?

Each application provides up to 30 days of protection against fleas, ticks, and other biting insects.

3-Does K9 Advantix II kill ticks?

Yes, it helps kill and repel ticks, reducing the risk of tick bites and related health problems.

4-Can my dog swim after applying K9 Advantix II?

Yes, the treatment becomes waterproof after 24 hours, so it continues working even after swimming or bathing.

5-How fast does K9 Advantix II work?

The formula starts killing fleas within 12 hours and continues protecting your dog throughout the month.

6-Can I use K9 Advantix II on cats?

No, this product is made for dogs only and should never be used on cats.

  • 5 stars: 18 (72%)
  • 4 stars: 7 (28%)
  • 3 stars: 0 (0%)
  • 2 stars: 0 (0%)
  • 1 star: 0 (0%)
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Rebecca

I’ve found the six-dose pack useful for keeping my dog’s flea and tick treatment organised. Each dose is individually packaged, so there’s no measuring or guessing involved. The application process is quick, which is helpful with a dog that doesn’t like sitting still for long.

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Daniel

The main thing I like about K9 Advantix II is the convenience. I don’t have to struggle with giving my dog a chewable treatment, which can sometimes be difficult. Applying the dose is quick and the packaging gives clear instructions.

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Sophie

I bought this for my dog before the warmer months and liked how simple the spot-on application was. The packaging is neat and the individual applicators are easy to handle. I haven’t had any issues with the product itself, although I think the price could be a little lower.

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Marcus

This treatment has been fairly straightforward to use. The individual doses are clearly separated, which makes it easy to keep track of monthly applications. My dog is in the 21–55 lb range, so the size was suitable for him. I also appreciate getting six doses in one pack because it saves me from having to reorder every month. Overall, a practical option for routine flea and tick care.

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Hannah

I’ve been using K9 Advantix II for my larger dog and have found the treatment easy to apply. The six-dose pack is convenient, especially when you want to keep up with regular flea and tick protection. The application doesn’t take long, and I like that there’s no need to give my dog a tablet. So far, it has been a useful addition to our regular pet care routine.

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Audreykensington

This has been one of the better flea treatments I’ve purchased. My dog had fewer fleas after using it, and the monthly doses are easy to manage. The product quality is excellent and the six pack provides great convenience for ongoing protection.

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Damianholloway

I’m satisfied with this flea treatment and its overall performance. It has helped keep my dog protected during outdoor activities. The packaging feels secure and the application process is straightforward. I would recommend it to anyone looking for dependable flea and tick protection.

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Clara Winslow

K9 Advantix II has worked nicely for my Labrador mix. The product is simple, clean and convenient to apply. I have confidence using it because the results have been consistent. The six dose pack is especially useful for long term pet care.

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Felix Thornton

Good quality flea and tick treatment that delivers reliable results. My dog had fewer issues after starting this product. I like the easy monthly schedule and compact packaging. It’s not the cheapest option available, but the effectiveness makes it a smart purchase.

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Naomi Westbrook

This product has become part of my regular pet care routine. The applicator is convenient and the treatment doesn’t create any hassle.

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Miles Kensington

After trying other brands, I decided to give K9 Advantix II a chance. It has performed better than expected. My dog stays comfortable and I haven’t noticed any tick issues. The product quality and convenience make it worth buying again.

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Lydia Ashford

I’m impressed with how effective this treatment has been. My dog spends time outside daily and we have seen a big reduction in flea problems. The product is easy to use, lasts for a month and provides good overall value.

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Everett Sinclair

This flea treatment has helped maintain my dog’s health and comfort. I like the simple application method and organized packaging. It works well for our needs, although I think clearer dosage instructions on the box would make it even better for first time users.

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Celine Waverly

I’ve had a positive experience with this product. It’s easy to apply and my dog tolerated it very well. The results have been consistent and I appreciate having a trusted solution during flea season.

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Theo Harrington

K9 Advantix II has been reliable for my large breed dog. The treatment absorbs well and doesn’t leave a strong smell. I like the durability of the protection and the fact that one box covers several months.

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Isla Beaumont

Great product with easy instructions. I noticed an improvement after the first application, and my dog seems happier without constant scratching.

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Rowan Callahan

This treatment has been effective for my active dog. We go hiking often, and flea prevention is important for us. I like that it works without needing daily attention.

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Vivian Montgomery

I’m happy with the overall performance of K9 Advantix II. It has helped reduce scratching and keeps my dog protected during warmer months. The six dose box is convenient and saves me from buying treatments frequently. I would purchase this again.

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Declan Whitaker

This product does exactly what I need it to do. My Boxer stays protected, and I haven’t had any major flea problems since using it. The packaging is neat and the treatment is easy to apply.

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Amelia

I bought this for my 50 lb rescue dog, and it has been effective. The design of the tubes makes storage simple and the monthly application schedule is easy to remember.

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Julian Everly

Very satisfied with this flea and tick treatment. My dog enjoys outdoor activities and this product gives me confidence that he is protected.

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Serena

K9 Advantix II has worked well for my German Shepherd. The instructions are clear and applying the treatment takes less than a minute. I appreciate that it provides protection against multiple pests.

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Mason Caldwell

I’ve used several flea treatments, but this one has given the most consistent results. The treatment works quickly and my dog seems much more comfortable now. The six month supply is practical and the product feels reliable. I would recommend it to other large dog owners.

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Eliana

This product has been a great addition to my dog’s care routine. My Golden Retriever had frequent flea issues before, but after using K9 Advantix II, the problem has reduced significantly.

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Adrian Whitmore

I purchased K9 Advantix II for my Labrador and I’m impressed with the results. The application is simple and the individual tubes make it easy to use each month.