Seresto Flea Collar for Cats Review

Will a Collar Keep Your Cat Flea-Free?


If you have a problem with fleas and ticks on your cats, you need to find a way to keep them safe without spending a fortune on products that do not work.

By the end of this article, we’ll give you the information you need to decide if Seresto is right for your furry family members, without wasting time and money.

Company Claims

Seresto Flea Collar for Cats will do two different things for your pet. It will repel fleas and ticks and kill any adults that are currently on your pet. It does take up to 48 hours to start working on ticks, so you may have to remove them manually until the collar has reached full saturation on your pet.

It also has a break away clip, so you pet will be able to escape if they are ever caught on an object while wearing the collar. It is also safe for your animal, even if they get the collar in their mouth and start chewing.

Active Ingredients

Seresto Flea Collar for Cats has two active ingredients:

  • Imidacloprid
  • Flumethrin

How Does the Flea Collar Work?

Imidacloprid acts as a neurotoxin in insects, causing them to lose control of their central nervous system. This leads to paralysis and eventual death. It is also slightly toxic to mammals and should only be used on the outside of your cat. It is one of the most widely used insecticides in the world but it is considered moderately toxic when ingested orally.

Flumethrin is similar to Imidacloprid except that it was developed to work on tick instead of fleas. It is nontoxic to mammals and did not show any adverse effects in any of its laboratory studies. It is used in this situation because it also neutralizes the adverse effects from ingesting the previous medication.

Usage Information

The Seresto Flea Collar for Cats is easy to use. All you do is remove the collar from the bag and place it around the cat’s neck. Adjust the tightness of the collar until one finger can be inserted under the band. This is different for cats because they have smaller heads and are more limber than dogs.

Snip off any excess collar that may stick out beyond the end of the clip. This prevents other animals from grabbing onto the collar and removing it from your cat.

The collar comes with a breakaway clip that will release if it is every caught on another obstacle. This prevents your cat from chocking on the collar and allows him or her to escape without harm.

What are Users Saying?

There were several reviews available for this product but all of them were negative. People who used this collar reported that it stopped working after only one or two months.

There were several reports of cats getting fleas again after the first 30 days and the owners had to switch to a different treatment to remove the infestation. There were also reports of ticks on some animals, but fleas were more common.

One review said that the collar caused chemical burns on the neck of their cat. This could be a case of a single sensitive animal, but this is a noted side effect of one of the medication.

Side Effects and Precautions

There are several side effects listed for Seresto Flea Collar for Cats. Some cats experienced skin irritation, redness, swelling, watery eyes and hair loss. There are also reports of some cats having seizures or lethargy after wearing the collar for several weeks.


We must give Seresto Flea Collar for Cats thumbs down. This is because of the number of negative reviews stating that the collar did not work. While we can expect any product to have a few negative comments, no matter how well it works, having nothing but negative comments is pretty clear.

There are several different alternatives, from topical treatments to oral pills, which have been shown to work. You may have to repeat dosages every 30 days, instead of every 8 months, but it is worth it to protect your cat from fleas and ticks.

If you’ve used this product, tell us about your experience in the comments section below.

43 Responses to “Seresto Flea Collar for Cats Review”
  1. Melissa says:

    Please do not use this product! My 15 lb cat lost down to 9 lbs and has chemical burns all around his neck after only wearing for 3 days! He is almost 5 and is a Bengal and has been understandable, very grumpy and not at all himself the past few days! I cannot believe I put my kitty through this!! This product is noooooo good!

    • Sheila says:

      Has your cat gotten any better. Mine became lethargic within 2 days & we took it off of her & it’s been down hill since then. We are nursing her along. I wish I had pul all that money I scraped up into a vet visit.

  2. Marcy says:

    Best product. Out there for a dog groomer living in the middle of Flea Capital!! I started seeing a lot of my customers coming in with the Seresto collars on and was not a fan at first… When some of the vets came in and their dogs had them I started to think about it.. I have 2 dogs and 2 cats . I bought them for my dogs first cause my one Schnauzer is allergic to everything.. Little nervous but after 4 weeks I was quite happy and turned around and got them for my 4 month old kitten and 5 year old cat who have been battling fleas for months .. 3 months later I’m still very happy no fleas no allergic reactions or anything!! I would recommend this collar to anyone .. Our grooming salon started selling them and they definitely SELL!!!

  3. Trish says:

    My cat has experienced chemical burn and hair loss

    • Trish says:

      To bad I can’t show a photo!!

  4. crondt says:

    We used Seresto on our 2 dogs a Boxer and a husky/german shepherd mix. I got to say that they had fleas so bad, we gave them 8 flea and tick baths in a week, at this point we drew to line and called the animal hospital and the told me to get Seresto collars and we love them!!!! They started working right away! Within 18 hours our 90lb fur babies was flea free!!!!!!! Thank you Seresto! The collars worked for about 7 months. I will only use Seresto from now on!

  5. Laura says:

    my cat appears to have burns around 1/3 of her neck. I took the collar off. It has helped with the fleas in the first few weeks but if I can’t keep it on the cat it isn’t going to work very well. The 2 other cats have limited raw places in the area of the collar. These cats are used to wearing a collar and could give two hoots about wearing a collar…they have not messed with it so that is not the issue here.

  6. keith says:

    Fantastic product. I had nothing but years of using different spot on’s bob martin frontline etc.etc. on my 2 dogs and 2 cats it was a nightmare all were fairly useless and worked for a very limited time. Seresto has been a godsend. Since fitting the collars its eliminated fleas and ticks completely to my relieved surprise. I’m now 6mths on and its still working well. Highly recommended! May seem expensive but its a bargain when you get the results for so long. I have a cupboard full of frontline and bob martin which was useless and regret ever struggling on with it now!

  7. Miriel says:

    My 4-year old cat wore this collar for about 3 weeks. After about 2.5 weeks he seemed a bit lethargic then started vomiting. I removed the collar and was horrified. His neck was bloody and raw as though burned both on top and below. We got him to the vet right away and he is now on antibiotics. Yesterday he was so lethargic and nonresponsive I feared for his life. After steroid/antibiotic as well as anti vomiting/diarrhea shots he is much better and has started eating again.

  8. Cheryl says:

    My cat experienced hair loss and severe skin irritation/chemical burns. I had to remove the collar 5 days after putting in on when I realized how bad the reaction was

  9. Jackie says:

    Bad product my cat has had the collar on for a few months and all of sudden he is acting funny starting losing hair so I looked closer to see if he had fleas and no fleas but a Bad Chemical burn all around his neck now we are not using this collar and are calling the vet

  10. Sheila says:

    3 of the 4 cats that wore these collars had problems. 2 had minor hair loss but the 3rd had serious chemical burns. I send all 4 collars back and would not recommend them.

  11. Dave says:

    I have 2 boxers and they have had it now for 4 months. Both of thier necks look like chemical burns and Raw. Bayer needs to recall this stuff and we need to get together and file class action. They are hurting our animals.

  12. Jeanie cornelius says:

    Love this product. Has been on my cat for 3 months and not one flea. The oral pill did great with her too but did not like that if she didn’t eat with it, she would vomit. Kinda hard to make a cat eat!!!

  13. jeannie sanders says:

    my cat monster would have been 11 oct 1 2016,but he die from pancreatitis,aug 4 2016 we had to have him put to sleep.after several months of wearing the seralto collar
    he was fine before we put it on hi i noticed him beenig leghrac then throwing up by that time it was to late he was at the vets from sat to thursday when we had to let him go.

  14. Jen says:

    Noticed a skin reaction on my kitty after about a week that at first wasn’t too bad. Since the collar information stated that an initial reaction may occur but should clear up in one to two weeks, I went ahead and left it on him, though quite loose, as it definitely was working as far as the fleas go. However, after about 3 weeks with the collar on, my baby kitty has a bright red, oozy/crusty, hairless strip on the side of his neck, about the width of the collar and an inch and a half long. I finally wrangled my 15 lb kitty into submission with a bed sheet and another person long enough to remove the collar. On the inside of it, dried blood all the way around the collar, and on my kitty’s neck, a scary looking moist chemical burn requiring a visit to the vet and a great deal of anxiety on my part. Along with the skin effects, my usually insanely spunky 18 month old Maine Coon has been depressed, lethargic, and agitated. This reaction seems to be a common theme for previously healthy kitties. So while I am disappointed that this hasn’t proven to be the miracle flea treatment I was hoping for here in FL(where flea control is a never-ending downhill battle even when attacked from all fronts), I am happy to get the collar off my kitty before it began to pose a critical health risk.

    The product does indeed eradicate fleas, and does so quickly; however, the potential health risks are disturbing. Should you choose to use the collar anyway, keep a very close eye on the skin under the collar and if you aren’t one of those lucky few whose pets seem to do fine with this collar, remove it at the first sign of the slightest skin irritation or lethargy.

  15. Tara Collins says:

    Bars on our experience, I DO NOT RECOMMEND Sereto flea collar. We outfitted two of our six cars- the two long hairs age 8 and 15, as they were the worst flea offenders.the older female became lethargic but the fleas did die off within 24 hours. The male didn’t do so well. Within the first 24 hours he started exhibiting what I can only equate to neurotoxicity: first he was lethargic, then his tongue was oddly sticking out. He slept at the top of my head which he never does which I now realize was his call for attention. This was followed by puffiness of his lower lip and the sagging of his bower jawline such so that you could see his gums. He was having trouble eating bad has a spastic tongue, he was having trouble keeping food in his mouth and working the tongue. The final straw was at the 24 hour
    Mark. His eyes were rolling around in his head, he was disorientated, had trouble walking, the sclera/second eyelid was prevalent and when he came to lie down on me, he became unresponsive. He had shallow breathing, twitching spasms which could be called seizures, and would not wake up with intense shaking. We took the collar off, monitored him all night and noticed a change I n his hair quality (coarse not soft) and missing hair around his neck. It has taken him 48 hours to be back to his old self. Granted the fleas were dead, but the cat was almost dead too. We forget that our cats are literally the size of babies. Some more sensitive than others but nonetheless the Seresto package says to keep away from children. I wouldn’t recommend this product but if you choose to use it, I’d monitor your cat carefully and go hour by hour. I’m glad we didn’t miss the Window for No Return.

  16. Margo says:

    Will never purchase again.My cat is having seizures, ripping fur out, litterally in chunks, pulling at her skin. Collar isnow off. Hoping i dont have to put her to sleep.

  17. Kelsi says:

    My cat has chemical burns and hair loss on his neck! This has been a complete NIGHTMARE!!!! Wish I could post a picture. DO NOT USE THIS ON YOUR CAT WITH SENSITIVE SKIN!!!

  18. Debbie says:

    I took the collar off of my cat after 3 days. She totally was not herself. She’s a 5 yr old domestic long hair. Stays inside 80% of the time and crys to go out the other 20. She quit crying to go out and lays all the time. Couple of times it was like she was in a trance. Eyes dialated and staring for minutes at a time. She has fallen off the cabinet a few times. I took the collar off because that is the only new thing introduced to her that could have changed her. Her energy, balance and appetite are gone. Emergency vet? Will see how she does after a couple of days without the collar.

  19. Helen says:

    After our dogs wore these collars with no problem, and two of our cats came home covered with ticks, we got them collars, too. No ticks, so that makes this collar a great item, but now one of my babies has been taking hair off of the back of her legs. This is so disappointing because these collars are so much better than anything I’ve ever used on them. And I’m not a fan of collars on cats, but…

  20. Virginia S Jones says:

    I have found that I can keep the collar on my cats for 1-2 days a week. My 1 cat got a total irritation after a week. But with limited use, still no fleas or the terrible deer ticks. I Would NOT keep this collar on for longer. My cats are almost 20 some products don’t work on them.

  21. Dene Greenway says:

    I bought seresto flea collar for my cat and he’s been wearing it about a week.Yesterday I was brushing him and noticed a sticky substance on his neck, upon further examination, I noticed he has a bare area around his neck (fur missing) and it was slightly bloody. I immediately removed the collar and washed ever so gently with warm water, I did indeed treat it with neosporin, which seemed to help. I did return this pathetic excuse for a flea collar and informed Walmart that this was a very dangerous product. How can a business, get away with providing the consumer with such an inferior and dangerous product. I’m telling all my friends not to purchase this product. BAD!!!

    I’m really upset that I chose this product and endangered my cats health. Also, he still has fleas.

  22. Dene Greenway says:

    My son Dennis also purchased this collar for his cat and had the same experience with this flea collar that I had. I just pray that these cats continue to survive and live a healthy and long life as was intended.

  23. Andrea Van Vorhis says:

    Have used Seresto collars on my dog successfully for a few years, but my cat had an almost immediate reaction to hers–severe skin irritation and hair loss around the collar. I am treating it with iodine and colloidal silver but will not use the collar on her again.

  24. Victoria B says:

    I put a Seresto collar on my cat Pebbles on December 16. Today, December 20, she was meowing in a way that made me concerned and when I went to pet her I noticed a sticky feeling on my hand by her head. She had bloody raw chemical burns and lost fur on the back of her neck where the collar was. She stopped meowing once I took the collar off, but is now sitting here acting quite subdued. It is a few minutes before midnight. I am counting down the minutes until I can take her to the vet in the morning. Very angry about this. I should note that my other cat has had one of these collars on since October and I have not noticed any problems, but now I am trying to find her so I can double check. I would feel sick to my stomach if my other cat has been suffering for months without my realising. I will never purchase these collars — which my vet pushed heavily — again.

  25. Hilary lobue says:

    One cat does great one cat gets skin irritation. Dogs do great, I have been using for 3 years and I love these collars.

  26. Colette P says:

    Got these collars for my 3 dogs and 2 cats. One of the cats lost a patch of hair onhis lower neck under the collar which was red and swollen. Definitely due to the collar. The other cat who is black and harder to detect if she was having any reactions seemed fine so I kept the collar on her. Now seven months later she has been losing hair on her hind legs. I’m pretty sure that it’s due to the collar. I have removed it in hopes that her hair will grow back. Both of my cats are indoor cats.

  27. Laura A. says:

    DO NOT BUY THIS PRODUCT!!! We bought this collar for each of our healthy cats. Within 2 weeks of wearing the collar, one of our cats began to act very lethargic and sickly, which is very unusual for her. She hid under the bed for days at a time, not greeting us like she normally would. We just assumed that she was hiding from our newly-mobile one year old who likes to play with her, but after a week of this unusual behavior, we noticed that she had a HORRIBLE chemical burn all around her neck. It is raw, and now completely hairless. I feel awful for not noticing it sooner. We immediately removed the collar and checked our other cat, who also had a chemical burn on the bottom part of her neck, though not as bad as our other cat, but still raw and hairless.

    When we spoke to the Vet Tech through the Bayer Hotline, she told us that this happen due to the active ingredient. I wish I would have known this ahead of time, so that I could have saved the money and my poor cat’s health.


  28. Karissa says:

    I bought 3 cat collars in September 2017 and put one on each of my cats. Two cats were <3 years old and the third cat was 18. The younger cats did not tolerate the collar at all and I suspect it was a factor in the complete acute kidney failure my previously healthy male experienced (we had to euthanize him as his kidneys were totally effed up and not recoverable. Devastating for a cat so young. Surprisingly my geriatric cat has done just fine with the collar and I replaced his last month. Now I’m considering taking the young female into my vet to test her kidney values to see if I can also expect to battle kidney failure with her. I will never recommend this collar for cats again. I’ve had zero issues with the dogs wearing these collars, however.

    • Debbie says:


      Mine got sick carried him to vet he died the next day. Kidney and liver failure the only 5hing we changed was putting the collar on him. I am thinking on sueing seresto

      Debbie Curtis

  29. Doc Suzers says:

    I am just devastated reading these stories. I too have used seresto on my cat. My cat was the picture of health when I put the collar on about a month ago and is now experiencing kidney failure and her hair will not stop falling out. The hair loss is all over her body, not just localized to her neck. After a $300 vet visit yesterday my only options are to begin an expensive treatment process that will not cure, only give extended life, or euthanasia. The only sign my cat was not well was that she began urinating all over the house. She has never done this before and is a 15 year old indoor/outdoor cat. I know correlation does not mean causation, but how many pets must die after beginning use of this product for the company to pull the product for more testing?

  30. Kat says:

    My mom purchased this collar for her cat against my advice. Within three days, the poor kitty shows lethargy and vomiting, and is dehydrated. I’m taking her to the vet today and hopefully she will pull through.

  31. Debbie says:

    Do not buy the product for you4 Catie killed mine

  32. Donn says:

    I am not certain if this is a problem…I have a 4 year old, dark color, domestic medium-hair who just started on the seresto collar in June. Collar is working great and no flea issues. She isn’t experiencing any of the symptoms others are describing…no hair loss, no rashes or burn, no disorientation, no lethargy….the only thing different is that her fur around her neck, up the back of her head and a bit towards her chest and back is now turning gray. Is this problematic? I am concerned..

  33. Ann Hudson8 says:


  34. elizabeth says:

    after one month my cat is making odd meowing noises and hs pooped in the house, i saw blood. just now whe was pooping outside and meowed oddly so i would look at her, and there was blood in her poop again. I am going to take the collar off, and maybe try 2 days a week.
    She had been on Advantage for ages and it didnt seem to work very well.
    the collar seems effective.

  35. Karen Lawrence says:

    We have 3 cats who all have Seresto flea collars and wearing them for a month.
    The short haired black cat and Himalayan cat are fine. But the tuxedo cat developed burns around its neck, scratching all the fine like she has fleas, but there is none. Took her to the vet yesterday after seeing the devastating burns. They shaved the area, gave her an injection, antibiotic, and used a flea vile. Which I should have used in the first place.
    The tuxedo cat continues to scratch herself raw and more places of bleeding.
    I am so disgusted with this product. I wish I knew about these effects before purchasing this item. I am cutting the other two collars off the cats. No since gambling in their health and paying a $1,000 vet bill of ongoing health. From reading simular cat reactions like our tuxedo cat, I think Seresto should be sued. Terrible suffering to watch an animal at its worst. I pray she will live.

  36. don mormon says:

    stinks. cat has terrible 3X 1 wound
    comments keep timing out. whole experience is crap

  37. Theresa D says:

    Do not use this product! It was highly recommended to me by our favorite Pet Smart guy. We asked our vet, and he said it had shown success in our county. We spent the $60 on the product only to see 2 weeks later that our adult cat had chemical burns on his neck. Not terribly bad ones, but definitely uncomfortable ones that eventually scabbed.

  38. AG says:

    I WISH NEVER PURCHASED FROM THIS COMPANY!!! AND ALSO WISH I CAN PUT PICTURE HOW BAD REACTION WE GOT!!!!! I have a coon cat and he stoped eating all day , when i went to pick up him exidently touched his neck and sure enough poor baby, imediattly saw a huge damage on his skin!!😫😫 The hair is gone , swollowed and infected Big time!!!! Hope he will recover from this chemical BS soon!!!!! EVERYBODY PLS DONT BUY THIS VERY VERY BAD PRODUCT!!!!! I am so angry at myself right now!!!!!!
    2018/ 10 / 02 😢😢😢

  39. AG says:


  40. Vee says:

    My mom’s cat has been using Serestro for 2 years and it is a godsend for them.

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