Seresto: Flea and Tick Control Made Easy

The Seresto collar kills fleas and ticks and is for use on dogs and cats

As a concerned pet parent, you know that protecting your four-legged friend from parasites like fleas and ticks is important. Topical pest control products can be messy and smelly, and with our ever-busy lives, it can be difficult to remember to apply every month. Have you ever wondered if there is anything new in flea and tick protection for your pet? Now available at PetMeds, the Seresto collar is the first new treatment in over a decade to offer flea and tick protection for both dogs and cats, and is also the first product to provide tick control for cats as well as for dogs. Best of all, it provides long-lasting coverage.

What does Seresto do?

The Seresto flea and tick collar provides effective control of fleas, flea eggs, flea larvae and ticks. The collar not only kills fleas and ticks, but repels ticks before they can bite, protecting your dog or cat from tick-borne diseases.

How long does Seresto last?

The Seresto collar lasts for 8 months

A Seresto collar begins working as soon as the collar is applied and will protect your dog or cat from fleas and ticks for up to eight months.  This innovative collar provides freedom from the inconvenience of applying a topical product to your pet every month, or trying to get your pet to take a monthly flea-control pill. It’s as simple as selecting the correct size collar and placing it around your pet’s neck.

How does Seresto work?

A unique polymer matrix allows the collar to slowly release controlled doses of the active ingredients, imidacloprid and flumethrin, over an extended period of time. Research has proven that the two active ingredients work synergistically together to dramatically increase their efficacy.

When placed on your pet, the ingredients in the Seresto collar are distributed on the outer surface of your pet’s skin and hair coat, where the ingredients come in contact with the parasites. The sustained release technology allows the migration of the active ingredients to adjust, depending upon the concentration of the ingredients within the lipid layer of your pet’s skin, thereby ensuring a steady, low-dose release.

What else should I know about Seresto?

The Seresto collar has a safety release mechanism

This innovative non-prescription collar is offered by Bayer Animal Health, and may be used on dogs 7 weeks or older, and cats 10 weeks of age or older.  It’s available for small dogs up to 18 pounds, large dogs 18 pounds and over, and cats of all weights. The collar is odor free, water-resistant and will continue to work even if it becomes wet or dirty, and the safety release mechanism prevents strangulation should the collar become caught or tangled.

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  1. This looks like a cool product that is going to work. Although I have always found pet wash experts and their techniques to be the best dog flea treatment for my pet. I would surely try this out too, but I am definitely not going leave my pet’s wash expert. They really do a great job.

  2. I would like to know just one thing. I was told that most collars just work around the neck area where they are worn. Does this product protect the entire pet? I would love someone to email me the answer to this question.

    Thank you

    • Dr. Michael Dym, VMD veterinarianMay 20, 2013 at 11:34 pm · Reply

      Most collars dispense the active chemical through the hair follicles throughout the coat.

  3. The Preventic Collar has to be strictly in contact with the pets skin. I have even seen some recommendations that you shave some of their pets hair around the neck so the collar is in contact with the skin. Is this similar?

  4. This is the best flea killer ever.. 1 month now and not a sign of a flea on my Shepard.. Getting ready to get one for my Yorkie.. So far-So Good

  5. NO, I put it on my Shepard with all his fur in tact.. do not shave.. believe me, I live in Southeastern VA-NC border…We have PLENTY of fleas here..He was miserable with any other product. Now, he is a new boy ……

  6. My dog has had this collar on for over 6 mos. While I was suspect, I think it did a decent job. It cost me about $70 and I have found ticks and fleas over the last few months. While I’m not totally disillusioned, I don’t think its 100% proof and my dog is not an outdoor dog nor is it around other pets much so why has he caught fleas/ticks even with it on ? I wonder!

    • Dr. Michael Dym, VMD veterinarianDecember 15, 2013 at 8:15 pm · Reply

      I am not big fan of these type of collars. I prefer topicals like flea 4x from 1800petmeds.

      • Melinda WilletteJuly 25, 2014 at 8:43 am · Reply

        Thank you, Dr. Michael Dym for your validation re: collars. Pls check my post re: very bad reaction with my puppy. Thank You, Melinda

      • Dr. Dym …as the Seresto Collar caused severe seizure like activity as posted here numerous times re: my puppy, I have also decided NOT to use ‘topicals’ either, for my puppy for fleas and ticks. I have been using FOOD GRADE Diatomaceous Earth, a non-toxic powder that can be rubbed into her coat and is even edible with no sdfx. I wish that more pet stores carried this..and as well, Customer Beware…MAKE SURE IT SAYS FOOD GRADE on the label and is NON-TOXIC. Some Diatomaceous Earth is used as pesticides and in pool filters (even being sold at pet stores, which I witnessed the other day) and some very popular websites on-line..VERY TOXIC to all animals! Hope this gives ALL an alternative..type in search, FOOD GRADE, Diatomaceous Earth (wholistic vets) and inquire, question ALL info!

        • Dr. Michael Dym, VMD veterinarianSeptember 24, 2014 at 10:50 am · Reply

          Thanks Melinda for the feedback. Diatomataceous earth is an excellent natural flea alternative

        • Thank you, Dr. Dym. Diatomaceous Earth is also used as a tick, including deer tick preventative – so a natural non-toxic option for both! Thank Goodness!

  7. I used the Seresto collar for large dogs on my 90lb German Shepard, Winston, last year. It worked extremely well, no fleas and an occasional dead tick. We live in the woods. So this year I ordered another collar. A week after putting it on Winston, WINSTON DIED. He started swelling after 5 days, fell down on evening of the 6th day, and died the morning of the 7th day in the Vets office. Be careful with this product.

    • Robert. First, Please allow me to send healing prayers. My dogs are my children and my heart is hurting for you.
      Are you 100% positive the Seresto collar did this to Winston?
      I think it must be made public far and wide if this is in fact what made him pass.
      While it worked fantastically for my Shepard, I am very scared to use it now as I take NO chances when it comes to my babies.
      Has it been diagnosed as the cause of death? I would ask you to please find out every answer, the hows, whys, and every other answer I could get from Bayer. We owe it to the people who Love their babies to pass on every tidbit of information possible. Please let us know everything you find out that has to do with Winston’s passing.
      I volunteer for many rescues and want to pass on all information I can get. I / We are all obligated to let it be known so we can save the lives of other animals.
      I, for one will never use Trifexis on any of my babies. My baby took one and within 3 hours I had her to the emergency vet. (they will still not say it was the Trifexis that caused this reaction.) It made every one of my babies sick (throwing up sick). Why would I want to give this poison to my babies if it has this reaction?
      Please get all the info on this for us as we are all only wanting what helps our Pets.
      I again am so very sorry for your loss. God Bless and Godspeed Winston.

      • Melinda WilletteJuly 25, 2014 at 8:39 am · Reply

        Sue, pls check out my post re: Seresto collar – BAD NEWS! Thank you, Melinda

        • I purchased Seresto and put the collar on my tea cup Yorkie Khloe…on the morning of the third day of her having it on she became blind and couldn’t walk within hours and died minutes later in my arms. At 10 years old I would love to say she died of old age. But I fear she did not and because I put this collar on her she died prematurely. Yesterday she was her lively self and wake this morning to blind, paralyzed little girl. I’m devastated and mad.

  8. Sorry, but Winston was already dead & cremated when my neighbor, who rescues dogs, told me about the Seresto. She had researched the product and did not use it on her dogs. She told me about the side effects and they seem to match up with Winston’s reaction prior to his death, loss of motor skills and shortness of breath. As I said in my prior statement, He wore the same collar all last year with no problems.

    • My vet told me to use Seresto and to discontinue the flea and tick preventitive (we live in the woods) but to continue with the heartworm meds. After hearing of Winston I’m not so sure! I’m going to have to do some more research! I’m with you Sue, and Winston, please give my Angel and Ginger a hug!

  9. Should my dog be taking Sentinel with Seresto collar? We switched to Sentinel after a bout of whipworms.

  10. I have my dog ware this collar but do can leave it if nned bath? let me know thank u

    • Dr. Michael Dym, VMD veterinarianJuly 11, 2014 at 4:05 pm · Reply

      I would take collar off if you bathe him and then reapply 24 hours after bath.

  11. Melinda WilletteJuly 25, 2014 at 8:32 am · Reply

    My vet recommended a Seresto Collar for my 6 month old Large Breed, Great Pyr/St Bernard. After 2 weeks of use, happening 3 different times, my puppy began a pre-seizure like dance then lunged at my face, (while standing) and tried to bite me. She did cause puncture wounds on my arms! I was very, very scared and NOT TYPICAL at all of my loving puppies behavior! I had her checked and not a behavioral issue – but rather reaction to collar as proved, removing collar and still six weeks later NO SEIZURE LIKE activity! I notified Bayer and they by law told me they’d notify the FDA! BE VERY CAREFUL of this product – IF YOU SEE any changes in activity/behavior for either cat or dog, REMOVE COLLAR!!!

    • Dr. Michael Dym, VMD veterinarianJuly 25, 2014 at 9:02 pm · Reply

      HI Melinda. Thanks for sharing. So sorry for your experience with this collar. On different note, I sometimes see this type of neurological issue come up after rabies vaccination, so I would be vigilant in monitoring for further relapses, especially after vaccinations.

      • Melinda WilletteJuly 26, 2014 at 6:24 am · Reply

        Dear Dr. Michael Dym, VMD – I so appreciate your feedback and help. I will be very diligent in reactions after rabies vacs or any other vacs. I have been wavering on a Lyme’s vac as my vet recommended – hearing pros and cons, I have decided not to, especially after this last experience and your info. Many, Many Thank You’s!

    • As an update re: Seresto Collar. Am seeing more and more posts re: seizure activity concerns from pet owners using a Seresto Collar for their dogs. I notified the FDA today and they were kind enough to send me back this email: It is NOT the FDA to report to – it is the EPA! Here’s the info to report adverse side effects to EPA:

      Thank you for contacting the FDA Center for Veterinary Medicine. I’m sorry to hear about your puppy’s illness and I hope she is doing much better now.

      The Seresto Collar is regulated by the Environmental Protection Agency (EPA). If you look at the package insert for the product, on the very bottom, you will find an “EPA Reg. No. 11556-1155”. This means the product was reviewed by the EPA for safety and efficacy.

      You can still report this to the EPA. The National Pesticide Information Center (NPIC) is a facility run by the EPA and Oregon State University. They take adverse reaction reports and they can also give you information about other topical pet flea and tick products. Their website address is: Their phone number is: 1-800-858-7378. Hope this helps.

    • Monique k medinaJuly 30, 2015 at 3:52 pm · Reply

      Hi.. I had the seresto collar on my dog for 3months.. Until recently he was fine.. 2 days ago i noticed he was going blind and had weak legs.. My question is i took it off today.. How long will the side effects last.. Thank u Monique

      • Has your dogs eyesite gotten better? Our dog has just started with blindness and only thing new is the collar

      • Monique, I’ve had the collar on my St. Bernard for about a month. He began tripping over his feet a couple weeks ago, and stumbling. Now he can’t stand up. The collar is the only thing different in his life. I removed it today! Now I’m seeing all these comments and am so worried. Did anyone reply to your question about hoe long the side effects last?

  12. My small 5lb chorkie is having episodes that last a few seconds and since my vet hasn’t seen them she isn’t sure what it is. They started after I put the Seresto collar on him, and about the same time he was diagnosed with a luxating patella. He stops, freezes, and yips for a few seconds, with his head down. No other seizure type activity and also doesn’t pull leg up or limp. He then walks away like nothing happened! Can it be a small seizure, or just pain? Should I remove the collar? I’m so confused and concerned.

    • Dr. Michael Dym, VMD veterinarianJuly 28, 2014 at 9:29 pm · Reply

      PRobably best Vicki to remove the collar as any topical pesticide may cause rare neurological or other reactions.

  13. Thank you, Dr. Dym for your quick response. I actually did remove the collar today. I purchased Sentinel at the vets office last week when he tested negative for heartworm I’m going to wait a few days and try it. Is it good for flea prevention also? I guess I’ll just check him thoroughly for ticks regularly. He’s only goes out when he potties.

  14. Our 2 yr old german short haired pointer started having seizures after being in the seresto collar about 10 days. He had 5 seizures in one day. We took off the collar and he has not had a episode since. oes anyone else know of this connection?

  15. Dear Vicki B and Barbie – I am so very sorry your precious pups experienced this as did my Snowy – (posted above)! That’s 3 of us NOW who experienced neuro- seizure like activity caused by the Seresto Collar…and ALL, once collar removed, became healthy again! To be honest, on the web, all I see is promoting this collar and I am furious!!! In addition, many vets, as did mine, highly recommend this collar. Yet, when seizure activity began, my vet suggested I put my precious puppy down! I REFUSED!! Removed the collar and she is fine – gentle and loving. This is a HORROR SHOW! Pls. report to FDA and as well would like to create a blogpost re: Seresto pro’s and cons. Any idea, Vicki or Barbie on how to do this??? I realize this is a public forum but I AM AN ADVOCATE..!!! Pls send a friend request to my f/b, “Melinda Willette”. Want to go behind the ‘smokescreen’!!!

  16. Could these terrible seizure-like reactions be caused by the combination of the Seresto collar used along with a topical heart worm preventative, such as Revolution or Heart Guard? I have done research on combining these treatments and have found none that approves Seresto be used with another preventative. There is a collar (Preventix?) that has been approved for a combined use. Any advice on this?

    • Dr. Michael Dym, VMD veterinarianSeptember 8, 2014 at 3:25 pm · Reply

      I find that combination products used at same time in sensitive pets may result in potential rare neurological reactions, which is why I always recommend animal guardians separate out products by at least 7 days.

  17. Good question. Our german short-hair is on Iverhart heartworm pills, and was before the sereto collar. Please let us know what you find out :-)

  18. I have two labs, a 3 yr old and a 12 yr old and they were wearing the seresto collars for the past 6 months. After hearing back from my breeder and reading these posts, the collars are in the trash. I admit we have not had one tick on either dog during that time. Coincidentally for the past 5 months the 3 yr old has been having seizures. The first seizure was 3 weeks after the collar was placed on him. The last seizure was a couple days ago and was termed as a grand mal seizure. I witnessed the whole thing and initially thought he dropped over dead. Then the spasms rather violently started, finally easing after a couple minutes. Blood tests were performed after the first seizure and compared to tests from the last seizure -everything was normal. What I find interesting is that the vet never recommended, even as a precautionary course, to remove the collar. I am now faced with giving him daily doses of phenobarbital to \maybe\ manage the seizures. Does anyone know how much time it takes to for a dog to be clear of the chemicals in the collar? Do the chemicals in the collar show up in general blood work? I am inclined to wait on giving him the phenobarbital and see if the collar may be the source.

    • Dr. Michael Dym, VMD veterinarianOctober 14, 2014 at 4:04 pm · Reply

      HI Jackie. Sorry to hear about your dog with seizures. All excellent questions. Hard to say if your dog is now a permanent epileptic, who will need life long medication, or possibly due to built up toxicity from the collar. Probably best thing is to proceed with the phenobarbitol medication and then if seizure free you could work with a local vet over time to gradually wean him off, but since we cant be sure whether drug is direct cause or just a trigger for the underlying epilepsy, then best to probably use the drug.

  19. I have 3 cats wear the sereto collars and my dog lso wear,too but they had been wear now for 2 yrs but they have no problems and good health but I do take the collar off for bath but great that all of them have no fleas but before had flea pills but was still haved lots of fleas .

  20. I have 3 cats and 2 dogs I bought Seresto collars for 2 months ago. Since that time, one cat has developed open sores and hair loss on her neck where the collar was, and my one dog, Amelia a 22 pound 11 year old beagle has developed clinical respiratory distress as well as having 3 different seizure episodes. An xray showed one lung non functional and possibly collapsed; no “Lung sounds” were heard using a stethoscope by the vet. She has developed a dry deep rasping cough, has excess fluid in her chest cavity and her breathing labored. She was administered a shot and prescribed Amoxi cap 50mg and furosemide 20 mg yesterday. Needless to say I removed the collar from all 5 pets last night. Today, Amelia’s breathing, while still more labored than it should be, is much improved and the coughing is greatly reduced as well. I have my fingers crossed that I caught this condition early enough to save her life, but time will tell. Between the reaction of Sami my cat, and Amelia to the Seresto collar I will never use a Seresto product again and I am sharing this information to warn other pet owners to be aware of what could occur should you decide to use it.

  21. I received two Seresto collars today from Dr Fosters and Smith after doing some research online and deciding it sounded like a great option in tick/flea prevention. We have a 14 week old German Shepard puppy and a 5 year old Keeshond. 4 hours after putting the seresto collar on our puppy, she started having a hacking cough like she was trying to vomit which she had never had before. She is watched like a hawk, and I know she didn’t get into anything. I looked online for side effects and couldn’t find anything other than what Bayer wants you to see. After more digging I came upon this website. I have taken the collar off both dogs as I just don’t want to take a chance that things will become worse. I am a RN, and am surprised that there is not more official information regarding incidence and type of side effects. I guess the old adage “if it sounds too good to be true, it probably is” applies to flea/tick prevention too. It would be nice if pet parents could truly make informed decisions with all the data.

  22. I put this collar on my cat, I want to treat for tapeworms. How long should I allow collar to work before worm treatment? Thanks!

  23. I put the Soresto collar on my two small dogs and noticed with days one of them was lethargic, couldn’t jump into the car or into the couch as she normally would, and she lost her balance very easily. She itched like crazy under her arm pits, she even lost her bowel control and then fell into the puddle of pee. Took her to the vet and all her blood work checked out normal. Vet thought she had some sort of lower back pain and treated her with pain meds. After two weeks she is back to normal but my sister suggested I look online for info about this flea collar. Since my other dog is fine and she is now fine I didn’t think it could be the collar but after finding all the reports of similar symptoms on Amazon and here on this site I am becoming more convinced the problem stemmed from the collar and at any point could happen to my other dog or to her again. I’m not risking it, I’ve removed the collars and will go back to Frontline or some other method. Very worrisome!

  24. have westies and we use advantage multi for heartwork and flea. We have used the preventic collar for ticks 6-8 months a yr and we have never found a live tick on our dogs.

    Was wondering if seresto might help or be better. Never had a flea but just wondered about changing?

  25. I was wondering if I could use sentinel while having the seresto collar on my dogs??

  26. We put the collar on my 9-year old Old English Sheep one week ago because she had fleas. Over the course of the week she’s had it on, she’s been scratching less…that’s the good news. This afternoon, she yelped in pain and couldn’t stand as her right back leg wasn’t working properly to support her. Finally, after several tries, she stood up, but started limping. I got her settled down and then she started retching. I got her outside where the retching continued, but nothing came up. I gave her water, which seemed to help. Then the leg issue came back and she struggled with walking. I took the collar off and she seems to be better now: no retching and no pain/yelping. I’m optimistic that her leg problem will be resolved soon now that poison is no longer coursing through her body.

  27. I put the Seresto collar on my 14 week old goldador and within hours she was coughing and heaving. She has been like that for three days. Not even considering the collar as a possible cause, I phoned the vet and she told me to bring her in tomorrow morning. It then occurred to me to look up possible Seresto side effects that Bayer may not have listed. Apparently there are a variety of them. I’m so glad that dog owners share their experiences! I removed the collar promptly! I’m hoping a bath and a few days will get her back to normal.

  28. Thank you to those who have shared details of adverse experiences with the Seresto collar. Our dog, a senior yet active bearded collie, had the collar on for five months. During that time, the dog seemed to go downhill, appearing at times to be blind or deaf, disoriented, and stumbling. We were concerned, yet never connected these problems to the collar until we happened to remove it for a few days after a bath. We were going to put on a new collar because the ticks weren’t all dying, but didn’t get around to it right away. We noticed some behavior changes without the collar and started to wonder, and I did some searches online. After reading this blog, we decided to keep the collar off and observe. In less than a week the symptoms of hearing, vision, and coordination problems disappeared and have not recurred. It has been a month since the symptoms went away and the dog is once again bouncing around as she was last year. We are so grateful to have our dog back. This product does not seem to be safe.

  29. seresto collar work great on my three dogs after two weeks all three would not eat, were lethargic, eating grass and constant diarhea, removed the collars and less than an hour later they were obviosly feeling better .two days later the diarhea cleared and my dogs are eating and back to normal activity, Bayer would not post my review on there website review , but they want me to call them directly, they emailed me immediatly but would not post my review apparantly only good reviews make itonline

  30. We received two Seresto Collars from a customer, who happened to be a vet. She swore this was the next new great flea control for pets. I put the collar on my Cayenne Kitty 4 hours ago. She threw up her dinner immediately and has not been moving much. So here I am reading all these posts and trying to decide if these are side effects. Like most of you, I can’t find side effects that include vomiting and lethargy, but what else could it be when a cat or dog just hours ago was completely fine and happy. I am taking the collar off now! Thanks to this site and the honest reviews to keep our pets, who are members of our family, happy and healthy. Please go to Amazon and read even more reviews and awful stories of the side effects of this product, it could save your pet!

  31. Vet put Seresto collar on my 13 lb. cat on August 28. Within a couple of days I noticed a very slight small skin irritation on the back of her neck. I applied a dab of Vetericyn and tried to move the collar off that spot. By the end of the next day, it was the size of a nickel, oozing and looked as if that spot had been burned or skinned. I have removed the collar, am treating the.sore and will report to the vet.

  32. I also used Seresto on both my dogs after my dad suggested it. His vet suggested to him for their dog. They have had it on little over a month and had no fleas or ticks. But I have noticed that they where scratching where the collars were. Now they have blisters and open sores on their tails one has had these blisters and sores under his armpit. At first I didn’t put the collar to be the cause until now. With both having the sores at the same time , both wearing the collars. I’ve taken the collars off and will be seeing the vet tomorrow. Its nonstop licking at the sores

  33. We purchased and placed the seresto collar for our lab puppy. Put it on her at 12 weeks, August 5th of this year. All was fine. We adjusted the collar as she grew so as not to be too tight. Last night we noticed sores on her neck. Not sure if this is due to her scratching at it or a reaction. She’s had the collar almost 3 months now and no reactions thus far. We are cleaning with soap/water and peroxide. If it doesn’t start healing within a day or two she will go to the vet. The collar was recommended by our vet. Has anyone heard of these type reactions. The collar is off for now.

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