Comfortis Chewable Tablet for Dogs 40.1-60 lbs (Blue Box), 6 Chewable Tablets (6-mos. supply)

By Comfortis
Rated 4.8889 out of 5 stars
Prescription Item
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Comfortis Chewable Tablet for Dogs 40.1-60 lbs (Blue Box), 6 Chewable Tablets (6-mos. supply) slide 1 of 4
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Comfortis Chewable Tablet for Dogs 40.1-60 lbs (Blue Box), 6 Chewable Tablets (6-mos. supply) slide 1 of 4
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$114.39Chewy Price
$108.67Autoship Price
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About This Item

Comfortis is a chewable medication prescribed by veterinarians for dogs to help treat -- and possibly even prevent -- flea infestations for up to one month. These flavored tablets can be added to your pet's favorite food and only need to be given to your canine companion once a month to help combat fleas.

Proudly sourced directly from the manufacturer or their approved distributor. Guaranteed genuine and backed by the manufacturer.

Play Video: Learn More About Comfortis From Our Team of Experts
Learn More About Comfortis From Our Team of Experts

Dosage Chart

Color on BoxWeight RangeStrengthDosageProduct Page
PinkDogs 5-10 lbs / Cats 4.1-6 lbs140 mg SpinosadGive orally once a month✓-Click Here
OrangeDogs 10.1-20 lbs / Cats 6.1-12 lbs270 mg SpinosadGive orally once a month✓-Click Here
GreenDogs 20.1-40 lbs / Cats 12.1-24 lbs560 mg SpinosadGive orally once a month✓-Click Here
BlueDogs 40.1-60 lbs810 mg SpinosadGive orally once a month✓-Click Here
BrownDogs 60.1-120 lbs1620 mg SpinosadGive orally once a month✓-Click Here

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ReviewsWrite a Review

Rated 4.8889 out of 5 stars
18 Reviews
Would recommend to a friend

18 Customer Reviews

Rated 5 out of 5 stars
By Catmom on Mar 2, 2022

Cat mom loves this!

I've used the smaller dose for cats for years for up to ten cats and it works when nothing else did, especially on my very thick furred cat whom the vet had to shave even to get a topical flea product on, which didn't work very well, anyway. With Comfortis, the fleas (multitudes of them!) started dying right away and the poor guy got comfort (so did I as he liked to cuddle very close to me). Just so distressed that everyone is out of stock for cats and praying that I can get it again soon. Used to be able to buy it over the counter but now need vet approval, so that's a kind of bummer.

Rated 5 out of 5 stars
By Dave on Feb 1, 2022


I have been looking for a non neurotoxic solution for fleas for years. Here in Little Rock the fleas are BAD! I’ve tried the plant oils based sprays that claim to work, and found them totally useless. For whatever reason, Comfortis had never popped up in a web search until my last one, not long ago. It sounded to good to be true, and wasn’t cheap either, but we love our pooch and she needed some relief! I had totally forgotten about making the order, after the extended time of waiting on the Vet Rx thru Chewy, but when the stuff finally came I started her on it. I kid you not; in 4 hours she was almost flea free, and by the next morning they were GONE!!! Our poor pouch FINALLY got the relief she needed, and is once again a calm, NON scratching, licking and chewing pooch! THANK YOU Comfortis!!!

Rated 5 out of 5 stars
By Danny on Jan 9, 2021

Works Very Well

Several years ago we had a bad flea infestation in my yard and no matter how many times I bathed my dogs and sprayed the yard and their bedding I couldn't get rid of them. I tried various flea collars, shampoos, sprays, and the tubes of flea killer you placed on their skin but nothing worked. My vet recommended I try Comfortis and within 3 or 4 days the fleas were gone from my dogs! Any time someone mentions that they're having flea problems I tell them to try Comfortis. It's not cheap but definitely works. They also make Trifexis which contains heartworm prevention too.

Rated 5 out of 5 stars
By Panda on Apr 20, 2021

Great thing to use

This was great. They contacted the vet and everything

Rated 4 out of 5 stars
By Judy on Jun 23, 2020

Flea Prevention

I have a dog with a severe flea allergy and an MDR1 status that requires care with medications. Comfortis was recommended for him 3 years ago by a veterinary dermatologist. It has done the job well, preventing further skin outbreaks. However, the odor from the tablets is awful, and strong! My other dog will not take this medication, even when hidden in food, and I can't force it down his throat. Fortunately, the dog that needs it tolerates it. So my recommendation comes with a qualification about the stench from this product.

Rated 5 out of 5 stars
By frog on Jun 3, 2020

My Great Dane approved!

I tried several topical flea/tick preventatives, but on 175# dog, they just didn’t cut it. So, I asked my vet. He recommended Comfortis, so I paid for it and my vet gave it to my Dooley before we left the office. By the time we got home, about an hour later, I could tell it was working. At that time, I had a huge yard, which was surrounded on 3 sides by woods, so ticks were also an issue. After him taking Comfortis, I didn’t see any ticks on him over the next couple of weeks either, so I asked my vet what was going on since this product is only supposed to repel fleas. He explained that it does work for ticks too, but for a manufacturer to make that claim, they have to go through a more rigorous testing process. Also, one dose lasted my Dane all summer long. I didn’t have to give it again. I’ve continued to use this for my American Bulldogs, and one dose lasts them the whole flea and tick season as well. I realize not everyone may have these same results, but even if this product didn’t over deliver on its promises, I would still highly recommend!!

Rated 5 out of 5 stars
By Missy on Jun 24, 2020

Fast shipping

Fair price on product and no fleas so my pup can rest,but even better was the fast free shipping. Even in a pandemic and requiring vet approval it arrived FAST! THANKS Chewy!!!!!!

Rated 5 out of 5 stars
By Sadpump on Aug 11, 2020

Works great

seems to help my dogs during the summer more than regular flea control

Rated 5 out of 5 stars
By PapaRay on May 6, 2020

It’s excellent

Been using Comfortis for couple of years, does great job keeping the fleas and ticks away. First time using Chewy RX, was very easy to put in vet info, fast turnaround.!

Rated 5 out of 5 stars
By Beesh on Mar 16, 2020

Good Fast Service as Usual

I recently moved out of CA for political reasons and did not have the opportunity to utilize Chewy's services. My order arrive in 2 days, "as usual" Thanks Chewy P.S. My dog has been on Comfortis for 5 years, no fleas at all!!