Comfortis Chewable Tablet for Dogs, 60.1-120 lbs, (Brown Box), 6 Chewable Tablets (6-mos. supply)
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Most prescriptions are delivered within 3-5 days.About This Item
Details
- Treats and prevents flea infestations caused by Ctenocephalides felis
- Kills adult fleas to help control active flea infestations
- Begins killing fleas quickly after administration
- Provides one full month of flea protection
- Contains spinosad, an oral insecticide that causes rapid flea death through neuronal excitation
Ingredients
1620 mg Spinosad.
Instructions
Dose varies based on pet's weight. Use according to your veterinarian's instructions. Comfortis is generally given once a month, but you should always follow your veterinarian's directions. It is recommended to give Comfortis chewable tablets with food.
Store at temperatures between 68° - 77°F.
FAQ
They’re beef-flavored, chewable tablets you give to your dog to kill fleas and prevent flea infestations for one month. Comfortis chewable tablets are recommended for monthly use in dogs 14 weeks of age or older and 5 lbs of body weight or greater.
Spinosad is the active ingredient in Comfortis. It belongs to a class of antiparasitics known as spinosyns, which are derived from a naturally-occurring soil microbe. It works by attacking the nervous system of insects, causing the rapid death of adult fleas.
Treatment can begin at any time of the year. Comfortis is most effective when given one month before fleas become active, with continued monthly dosing through the end of the flea season. In areas where fleas are common year-round, monthly treatment with Comfortis chewable tablets should continue through the entire year without interruption. To minimize the likelihood of flea re-infestation, simultaneously treat all animals in your household with an approved flea protection product. Consult your veterinarian for the flea treatment options most appropriate for your area. See also, what should I discuss with my veterinarian regarding Comfortis for my dog?
Spinosad, the active ingredient in Comfortis, began killing fleas in 30 minutes and killed 100% of fleas on dogs in just four hours in controlled laboratory studies. Comfortis chewable tablets kill fleas before they can lay eggs.
Comfortis has demonstrated full effectiveness for an entire month.
Comfortis kills fleas before they can lay eggs when used monthly, according to the label directions. If you see fleas on your dog within a month after your pet receives Comfortis, they are most likely new fleas. Because your pet has been treated with Comfortis, these new fleas will be killed before they can produce eggs that contaminate your home. Continued monthly use of Comfortis can prevent any new flea infestations.
Your pet can experience continued exposure to fleas living in the environment. It’s important to treat all animals in the household with an approved flea product to help control the flea population. Learn more about controlling flea infestations in your home.
Comfortis has demonstrated to be safe in healthy dogs when used according to label directions. Use only for dogs and puppies 14 weeks of age and older and 5 lbs of body weight or greater. The safe use of Comfortis in breeding, pregnant or lactating dogs has not been evaluated.
Comfortis contains beef flavoring made from a pork-based protein. If your pet has an allergy to pork, you may need to consider an alternative for flea treatment and prevention. Please discuss these options with your pet's veterinarian. The use of ivermectin at higher than FDA-approved doses at the same time as Comfortis can result in serious side effects.
As with any medication, sometimes side effects occur. See the Comfortis label for complete safety information.
The following adverse events reported for dogs are listed in decreasing order of reporting frequency: Vomiting, depression/lethargy, pruritus, anorexia, diarrhea, seizures, ataxia, trembling, behavioral changes, and hypersalivation. Following concomitant extra-label use of ivermectin with COMFORTIS, some dogs have experienced the following clinical signs: Trembling/twitching, salivation/drooling, seizures, ataxia, mydriasis, blindness, and disorientation.
Administer Comfortis with food for maximum effectiveness. Because Comfortis is a flavored tablet, it can be offered just prior to or just after feeding. You can also administer Comfortis as you would other tablet medications. Visit the Dosing & Administration page for more details, or download the Comfortis label. Each box includes reminder stickers for your calendar to help remind you to administer each dose. You can also sign up for monthly text or email reminders.
In field trials, dog owners were instructed to give the Comfortis tablet with food. However, the quantity of food was not specified and Comfortis was still effective. An option is to give Comfortis immediately before a regularly scheduled meal. For free feeders (dogs who nibble throughout the day), you might take food away at night, administer Comfortis first thing in the morning, then put the food back down.
Give your pet his or her regular dose immediately, then resume a regular monthly schedule. To help you remember to dose your pet, sign up for monthly email or text messaging reminders. For complete safety information, view the Comfortis label.
Contact your veterinarian if you believe your pet has ingested more than the recommended dose of Comfortis. Visit the Dosing & Administration page for more details, or see the Comfortis label for complete safety information.
No. You can continue normal activities and interactions with your pet.
Comfortis is not contraindicated for use with any veterinary drug/product when they are administered at labeled doses. However, while labeled heartworm preventatives are not an issue, you should not use Comfortis concurrently with extra-label doses of ivermectin in dogs. Make sure your veterinarian is aware of all products that you intend to administer to your pet. In well-controlled field studies, Comfortis chewable tablets were administered safely in conjunction with other frequently used labeled products, such as vaccines, anthelmintics, antiparasitics, antibiotics, steroids, tick control products, anesthetics, NSAIDs, antihistamines, alternative/herbal remedies, shampoos, prescription diets, and most generally prescribed medications.
Your veterinarian is your pet's healthcare expert and can make the best medication recommendations. This includes the prevention, control and/or treatment of parasites such as fleas, heartworms and intestinal parasites. These parasites can cause conditions including flea allergy dermatitis, anemia and heart disease. Key points of your discussion might include:
- The best time to start flea treatment in your geographic region.
- What administration method will work best for your pet.
- What to do if you miss a dose of Comfortis.
- What other medications you give your pet.
- What to do about a severe flea infestation.
- What steps you can take to prevent a flea re-infestation in your home.

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Customers Mention
Ease of Use
Effectiveness
Ingredients
Long-Term Benefits
104 Customer Reviews
Safe for your pet
I'm pretty funny when it comes to me giving my dog pills for everything but I have large dogs which comes large problems. I stumbled upon this at the Humane Society
I'm pretty funny when it comes to me giving my dog pills for everything but I have large dogs which comes large problems. I stumbled upon this at the Humane Society Vet in my town and have stuck with it for years now. My dogs can take this on an empty stomach wrapped in something pill pockets ect. I keep the animal in for the next 3 hours so they don't try and eat grass and then get sick. They ingest the pills and in the next few hours you can see the fleas dying.My dogs got fleas from the squirrels in my yard and were misereable a few hours after this they are all so happy to not have fleas. Has a flowery smell to it so my dogs can smell when its coming so mask it.
Effective without extra chemicals/pesticides
Our boy is very sensitive to chemicals and we try to limit them as much as possible. However, we had a flea issue pop up in 2024 and had to use something stronger
Our boy is very sensitive to chemicals and we try to limit them as much as possible. However, we had a flea issue pop up in 2024 and had to use something stronger. Comfortis was the "safest" option we found and did the trick immediately. We were amazed and have continued to use it during flea heavy times of the year. I will say that the pill is massive, so we cut it into 4 pieces and try to hide it in treats. We've only had an issue once because I think the smell is pretty strong. Just make sure to disguise it!
Only ONE Preventative at a time!!
This product just WORKS! I dint give my boy the "All-In-Ones"! I had a really bad experience when he was 6mo this old after giving him a popular "All-In-One", and
This product just WORKS! I dint give my boy the "All-In-Ones"! I had a really bad experience when he was 6mo this old after giving him a popular "All-In-One", and he almost died. He developed IMHA rapidly after giving him his "All-In-One" preventative, so every since then, he gets his flea meds separate from his Heartworm, and the tick preventative only when we are planning a trip out into the sticks. We don't have ticks on the island where I live, so that makes it easier. As long as I give them one at a time, he is fine, so I will continue to do just that, and I have been giving Comfortis to all the dogs I have had, for over 20 years with no issues whatsoever. I also like it because the active ingredient is a natural extract of Spinosad, which is extracted from nematodes that live in the soil. I wasn't happy when Comfortis started switching it up to an "All-in-One", and was so very happy when they discontinued the All-in-One" and went back to the "just Spinosad" treatment. Thank you Comfortis for going against the grain of what all the other companies are doing!!! My beautiful, sweet boy thanks you too!
The best
Comfortis is the one flea product that actually WORKS. I've been giving it to my dogs and cats for over 10 years without any health issues. My local Veterinarian
Comfortis is the one flea product that actually WORKS. I've been giving it to my dogs and cats for over 10 years without any health issues. My local Veterinarian stopped carrying it, when Comfortis briefly discontinued their product to revamp their packaging, so thank Goodness for Chewy!! I'm still able to keep my pets protected from fleas. I live in the Flea Capital of the world (Florida. LOL), so it's important to keep them protected year round.
So Disappointed
I have been using Comfortis for three years. I have 14 rescue animals so it is very important that fleas/ticks are not an issue in my home. Sadly, I noticed my
I have been using Comfortis for three years. I have 14 rescue animals so it is very important that fleas/ticks are not an issue in my home. Sadly, I noticed my four dogs scratching up a storm. They all get Comfortis on a monthly basis, but it is no longer working. Now I have to spend A LOT of money buying a new preventative which I really hope it works.
Wonderful product
When we moved in with my mother in law to help take care of her. We had a Coocker Spaniel he did not have fleas till then and I heard Abigail this product I tried
When we moved in with my mother in law to help take care of her. We had a Coocker Spaniel he did not have fleas till then and I heard Abigail this product I tried everything else first and nothing worked I gave him that and by the next day I didn't see any more fleas on him. And when my mother in law passed away she asked us if we would take care or her Australian Shepherd and he had hair missing because of fleas so we started giving him this and his hair came back and he no longer is digging at his skin.
I came back!
My vet quit carrying Comfortis, which I had been using for years. He directed me to use Advantage Multi. After using it on the dogs I own, I found, over time,
My vet quit carrying Comfortis, which I had been using for years. He directed me to use Advantage Multi. After using it on the dogs I own, I found, over time, that it just wasn't working good. My dogs began loosing hair, also. So I asked for a prescription for Comfortis and upon the first application, it worked. Thanks Chewy! and Thanks Comfortis! Our lives are back to normal.
One tablet last months, even years.
I have three dogs. If I treat all three at the same time with Comfortis, it rids not only my dogs of fleas, but my house as well. I'm not sure how that works, but
I have three dogs. If I treat all three at the same time with Comfortis, it rids not only my dogs of fleas, but my house as well. I'm not sure how that works, but it does. While described as a monthly treatment, I find that unnecessary. I just wait until I see fleas again. I had to treat them this week; but before that, my last treatment was so long ago that I don't remember it. It's been literally years.
Greatest Flea Medicine EVER!!
I have used Comfortis for years and swear by it. It starts working within an hour. I had a flea infestation on my pets and in my house. I gave my dog a pill and
I have used Comfortis for years and swear by it. It starts working within an hour. I had a flea infestation on my pets and in my house. I gave my dog a pill and vacuumed daily and it was cleared up in a week!! I find it works longer than 30 days so I stretch it out to one tablet every 45-50 days. I highly recommend it, it's worth every penny!!
This has worked
Fleas are an issue this year, never prior. I tried every natural product which would more than likely work if it wasn't a horrendously bad year of flea explosion
Fleas are an issue this year, never prior. I tried every natural product which would more than likely work if it wasn't a horrendously bad year of flea explosion. I'm extremely hesitant to use anything chemical but had to give in and after researching decided Comfortis would do the least harm to the dogs. Ticks have not been a problem so I couldn't see also adding that chemical into their bodies.



