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

  3. Dr. Michael Dym, VMD veterinarianMay 20, 2013 at 11:34 pm

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

  4. 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?

  5. 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

  6. 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 ……

  7. 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!

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

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

  9. 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.

  10. 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.

  11. 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.

  12. 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!

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

  14. Dr. Michael Dym, VMD veterinarianJune 2, 2014 at 6:10 pm

    I dont think this will be a problem.

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

  16. Dr. Michael Dym, VMD veterinarianJuly 11, 2014 at 4:05 pm

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

  17. Melinda WilletteJuly 25, 2014 at 8:32 am

    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!!!

  18. Melinda WilletteJuly 25, 2014 at 8:39 am

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

  19. Melinda WilletteJuly 25, 2014 at 8:43 am

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

  20. Dr. Michael Dym, VMD veterinarianJuly 25, 2014 at 9:00 pm

    You are very welcome Melinda

  21. Dr. Michael Dym, VMD veterinarianJuly 25, 2014 at 9:02 pm

    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.

  22. Melinda WilletteJuly 26, 2014 at 6:24 am

    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!

  23. Dr. Michael Dym, VMD veterinarianJuly 26, 2014 at 8:15 pm

    Glad to have been of service to you….

  24. 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.

  25. Dr. Michael Dym, VMD veterinarianJuly 28, 2014 at 9:29 pm

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

  26. 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.

  27. Dr. Michael Dym, VMD veterinarianJuly 30, 2014 at 11:14 am

    Sentinel is good for flea prevention a swell.

  28. Since this post in May, I have taken the Seresto collar off of my dog. The sores and flaky skin have resolved and he no longer has “dandruff.” He is still taking Sentinel.

  29. 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?

  30. Dr. Michael Dym, VMD veterinarianAugust 6, 2014 at 2:05 pm

    Any topical pesticide may cause seizures in a rare case in sensitive animals.

  31. Dr. Michael Dym, VMD veterinarianAugust 6, 2014 at 8:19 pm

    Thanks for sharing

  32. 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’!!!

  33. 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?

  34. 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 🙂

  35. Dr. Michael Dym, VMD veterinarianSeptember 8, 2014 at 3:25 pm

    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.

  36. 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.

  37. 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!

  38. Dr. Michael Dym, VMD veterinarianSeptember 24, 2014 at 10:50 am

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

  39. 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!

  40. 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.

  41. Dr. Michael Dym, VMD veterinarianOctober 14, 2014 at 4:04 pm

    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.

  42. 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 .

  43. 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.

  44. Dr. Michael Dym, VMD veterinarianNovember 9, 2014 at 5:25 pm

    Sorry to hear about your experiences. Hopefully all will be ok.

  45. 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.

  46. Dr. Michael Dym, VMD veterinarianMarch 18, 2015 at 12:38 pm

    I am so sorry to hear of your loss.

  47. 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.

  48. 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!

  49. 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!

  50. 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?

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

  52. 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.

  53. Monique k medinaJuly 30, 2015 at 3:52 pm

    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

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

  55. 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?

  56. 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.

  57. 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.

  58. 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

  59. 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!

  60. 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.

  61. 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

  62. That’s the kind of sores my dogs have

  63. 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.

  64. DO NOT BUY THIS PRODUCT! ITS NOT WORTH THE RISK!!! I purchased the Seresto collar for my dog because my vet recommended it. I did the research before buying it and did see other posts here and on amazon about negative side effects others have had with their dogs, which were all worrisome to say the least. However with any product such as this there could be side effects, you just never know how your dog may react to it. I’m glad I already knew what to look out for when I tried the collar on my 2 year old girl, Coco. Otherwise I might have kept it on her longer than I did. Within 2 hours of putting the collar on, she became lethargic. She is normally social and happy with a steady energy level, but she just laid around looking kinda ‘out of it’ all day. On a walk we took the first day the collar was on, she fell down or tripped, kinda like one of her legs gave out while walking (this was strange, definitely!). I rationalized it and thought, “Ok, give it another day and maybe her behavior today was just because she was tired”. So, the next day, she seemed almost hyper and anxious, and wasn’t behaving as she normally does. She was also scratching her neck all the time where the collar was. Her face had also become a bit swollen right around her nose/nasal passages. That was all I needed to see, I removed the collar immediately after 48 hours. The state of California has banned this product, and I wish that Bayer was held accountable for these side effects, or at least they would be forced to publish the potential risks on their website before people purchase this any more. Thanks everyone for sharing their experiences, hopefully it will help other parents and save their dogs/cats from any more pain.

  65. I have used these collars on both our dogs. We have a mini doodle and a yorkie. No problems at all however I recently purchased one for our stray/ indoor/ outdoor cat and have found no fleas but I have found a couple ticks on him. I didn’t think the ticks would stay and bite but they did. Not sure what to think .

  66. I have a 2 yr old Siberian Husky that started having seizures (3) after wearing the Bayer Seresto Flea Collar. After coming back from the doctor and searching online on what it could be since all vitals and blood test were perfect We read about the link between the flea collar and seizures we instantly removed the collar, (coincidence or not) He hasn’t had another seizure yet 3 days later. We also scheduled an appt with a Neurologist, all tests were normal. So now we sit and wait, praying for the best

    Please note that Vets ( i was told this by the Neurologist) do not consider this a possibility for the simple fact that there is nothing documented “by Vets” online about this link between the collar and seizures.but what about all the owners that are seeing their pets go through this and writing about it? Upsetting to say the least.

  67. I have a 10 year old Boston Terrier who has been wearing a Seresto collar for 7 months. Took him to his primary vet last week because the dog was having trouble seeing. Primary vet confirmed he has cataracts and sent me to an eye clinic. This doctor says that yes he has cataracts but not bad enough to affect his vision so dramatically. Diagnosis/Problem: Left – vision + normal light response – less than normal vision Right – No vision – No light response – Optic Nerve Problem –

    Cataracts Hereditary – minor – not affecting vision
    Advise Neurology evaluation

    I have an appointment w/the Neurologist early next week

    Took the collar off today. Hopeful that vision will improve. I’ll let you know.

  68. Update: Last Thursday my Boston’s eye doctor told me to remove the collar and bathe him with warm “not hot” water and a small amount of dawn dish detergent. I went to the neurologist and she had a MRI done yesterday, Wednesday. She also prescribed a steroid Prednisone 5 mg tablets twice daily. I have a 30 day supply. Awaiting the evaluation of the MRI by the radiologist –

    Neither my dog’s eye doctor or neurologist were familiar with the Seresto collar. After I told the eye doctor about it he looked up the product information and confirmed that there is an ingredient that may cause neurologic problems.

    Will update blog post when I get the results from the MRI.

  69. The neurologist just called. He has a tumor a bit smaller than a grape against his pituitary gland that’s pressing on his optic nerve. She believes it’s benign but it is inoperable. She will continue on with the steroids and order a change in diet, herbs and another drug hoping to reduce the tumor and to prolong his health. As the tumor progresses we can expect seizures, headaches, rolling, blindness etc. She says that she has seen dogs in similar condition that have an enjoyable life for 2 months to 18 months.

    He seems very happy and active now so we’ll just have to make the best of it

  70. My Shorkie and Morkie have been wearing the Seresto collar for about 3 months. While they haven’t experienced neurological issues and seem to be tick free they are not flea free. It is very frustrating that we continue to have flea issues after spending $140 on collars. My Morkie is diabetic and had cataracts removed two years ago. I hate doing anything that will adversely affect her eyes or glucose level. I would much prefer an organic solution. Is there anything on the market or homeopathic that works well for flea and tick control?

  71. Yes I tried this collar for the last 5 days, I noticed that all the fleas and ticks died. I noticed he became lethargic, and then started getting diarrhea after the fourth day. I called the manufacturer Bayer, and they said: “no it wont cause lethargy we tested this product to the extremes, and it has no side effects”. Oh well, guess you cant believe everything you hear, and today life’s not all that fair. I immediately took off the collar, and today I’m giving him a bath with a mild soap to wash the chemicals off. Thank you for the helpful comments on this website!

  72. Hi Leona, heard that the food grade diatomaceous earth is good!

  73. I bought the collar on thursday and my 7 year old pug started wearing it thursday evening. By sunday, I thought she was acting peculiar and she was her losing appetite. On monday, she exhibited lack of interest with most everything. I got down on floor with her and tried to get her to play, when I smelled something foul. Upon closer examination I decided it was coming from her neck area. I immediately took her collar off and it was then I seen two very raw spots. Im sure the collar was not too tight and perhaps she is sensitive to having something around her neck. However, she does wear a harness when we walk. The foul smell was a very strong medicine like smell, but once the collar was removed, the smell subsided. My pug has been completely healthy her whole life, I am convinced this collar was making her I’ll as well as rubbing her neck raw. So please be careful when introducing something new to your furry family members.

  74. My dogs, mixed breed rescues; 8ish and 11ish, wore Seresto collars for about 9 mos. No problems until recently when my vet found a tumor/cyst on the 11 year old’s neck a month ago. I just found a similar tumor on my other dog. I haven’t found any articles discussing correlation between this but I find it more than coincidental that both dogs (not related) have this in similar areas. Does anyone have any information. Prior to this collar I used the topical ant-flea/tic product.

  75. I just researched and went over the above study with a fine tooth comb. I have 4 collars sitting in my pet drawer right now as I am awaiting flea and tick season. I live in southern new jersey. I will NOT however put a collar on my pug as he had a seizure years back after using Advantix on him. After reading the study I am going to try the Seresto collar on my 4 dogs. I will watch for side effects. According to the the study, the smaller amount of medication which is time released is safer then dumping a whole tube of pesticide on an animal all at once. This does make sense. I have used Advantix II on my flea bite dermatitis german shepherd and he had a neurological episode within a week after application. I will try the Seresto. Hope the above report helps some who are worried about the safety of these collars.

  76. We have a huge tick problem in my area. We tried some different meds and nothing seemed to really work. We tried the Seresto Collars on our 3 dogs last year and they worked and the only thing that has worked as well. It’s great also that they work for so long. I feel bad for anyone who has lost their dog but Ticks here in the southern woods can totally infest a dog in no time. We tried other flea collars but they didn’t seem to do anything at all. We also tried frontline etc. Though Frontline did help but not as well as the seresto collars and not nearly for so long.

  77. Thank you all for your comments re; Surest. My dog 13 lb. dog has had the collar on for 24 hr. & I’m having breathing issues.
    It may be effective but it’s not safe for pets or humans

  78. I’ve used the Seresto collar for 2 years after moving to VT… rural, woodsy and so many ticks you have them all the way up to your neck after a 5 minute walk outside. We’ve had no problems with the collar… I know people who try all the natural remedies and still get ticks. And I also know a huge amount of dogs who have ended up with tick borne diseases… It’s alarming to use anything chemical on your pet, but the alternative isn’t great either. And since she’s had no effects and no ticks… I’m sticking with it!

  79. Put the Seresto collar on my 1.5 year old, 8 lb Yorkie less than 24 hours ago and the underside of neck is now swollen, red and getting inflamed. Took it off immediately and gave him a bath. Will opt for something more natural.

  80. After my ex realized he was allergic to our 7 year old 100 lb.GSD, so I brought him home with me. His skin was dry and he was scratching a lot. I took him to the vet Tuesday night. He gave him an antihistamine injection, three meds and put a Seresto collar on him. I asked if it was safe since I have a Shipoo as well. They assured me it was.
    I spoke with the vet Thursday to let him know the scratching had subsided, but he was vommitting after eating and drinking. I was told that maybe the Cefpodoxime was upsetting his stomach, so I told them I would stop giving it to him. No mention was made of the collar. My ex told me he gets sick if he eats and drinks too fast. I split his meals and gave him only sips of water. He vomitted four more times in two days. Today, Saturday, he was sick again after drinking only water at the park. Tonight, after getting sick twice, I realized what was different was the Seresto collar. I took it off and washed his neck. Then I started reading this blog. I’m sitting on the floor praying I don’t need to wake someone up to help me get him to the emergency vet.

  81. I wish I read this sooner……. I used seresto collars on all four dogs, two Cane Corsos and two small dogs last year. The male Corso had two seizures in November. It is March 2016 and he had a seizure about a month ago with no collar on, then we put collars on again for this season 11 days ago. 7 days ago he had a seizure and two days ago he had two seizures. He has been lethargic for about a week. Very early this morning he was having trouble breathing, his back legs were giving out, he went blind, was disoriented, then became unresponsive and died less than three hours after waking up with breathing problems. The vet said he believes it was a brain tumor near the brain stem because everything happened so quickly. I am not so sure that was it after reading the posts here. And yes I am a real person who loves, and loved, his pets dearly. I don’t know if it was the collar, but they are coming off. It hurts too much to take the chance. The collar worked against ticks, but my dog was only six.What else is out there for ticks?

  82. Hi John. We’re so sorry for your loss. You might ask your vet about some of the new chewables, such as Bravecto and Nexgard, that protect your dog against fleas and ticks .

  83. We were quite upset when our 5 year old Cockerpoo started to have seizures! WE never knew that Sorresto was linked to this condition and we have removed the collar and we are hoping the seizures end.

  84. Our indoor short-haired cat has been experiencing first facial focol seizures, and now grand mal seizures. My husband bought this flea color for both our dog and cat. Our dog is allowed off lease at the coast and gets fleas, which she brings into the house. Within a week of having the collar on him, the cat became larthargic. The following week he started yowling, within two weeks he was seizing. Because he is indoor, I wondered if the collar was the culprit. We’ve not added anything else new to the environment and hadn’t changed his food or litter. Within 24 hours he wasn’t yowling anymore, but the seizures started. We’ve been to two vets — one emergency and the regular vet. Blood tests are normal, so it is believed he was exposed to a toxin. Our regular vet has reported this. I’m sick to think we may have caused this. Our cat was an otherwise healthy, very active, playful part of our family. We are likely going to have to start him on anti-seizure medicine. I will never buy this product again.

  85. I have not used Seresto, but my dog began having seizures shortly after applying K9 Advantix II on her 2 years ago. She ended up having to go on phenobarbitol and we were finally able to wean her off after almost 2 years on the drug. We switched her to Nexgard, oral flea med and she has been fine. I would possibly consult your vet for meds if the seizures don’t subside and definitely use caution with topical flea meds.

  86. We were given Seresto flea collar from our vet for our 4 year old German shepherd. similar to other posts the dog became unwell and started having seizures. After learning there was some association with the collar (which our vet denied all knowledge of), we removed the collar and the seizures have stopped 7 months now, and he is back to himself.

    Worryingly we have a home abroad, and are now not certain if he has been sensitised and wont be able to have a rabies injection, in which case we have a huge dilemma. I would never recommend this to anyone.

  87. We put Seresto collars on my 9 year old bichon/yorkie mix and 14 week old english setter/pitbuill mix last night. This morning my husband saw the puppy have diarrhea and she is breathing fast. He took off the collar and he said she seemed better a few minutes later. He’s calling the vet now. We’re not sure if it was from wearing her collar for 12 hours or from wrestling with our older dog, she is still very mouthy and bites the neck area so may have had oral exposure to his collar. I had my husband take the collars off both dogs. Hoping she recovers fully and does not experience the issues others have reported here.

  88. Hello my vet referred me to seresto collars for my border collies one is a year old and the other one is just 10 weeks old. We live in a wooded area and always end up with a flea festation every year and I’m looking for the best solution and after reading about seresto collars I’m not too sure I wanna pay $45 to have an unwell pet or possibly fatality. Can someone give me some effective products to use other the this collar?

  89. I saw the advertisement of Bayer Seresto on TV and thought they were perfect for our Jack Russell Terriers. About 2 weeks later our 10 year old healthy JRT started having Seizures. He was put on IV Valium then Keppra. I asked my Vet if it could be the Seresto, she said no. Our JRT was doing fine on the Keppra, then started having Cluster Seizures. He was put on Potassium Bromide along with the Keppra. After reading all these horror stories I feel like a complete idiot. My poor baby had to of been sick because of the Seresto. I feel so terrible, I shouldn’t of believed our Vet. I’m in human medicine and trusted her. I’m going back to the cheap Hartz flea drops, my Jacks never had a reaction to them…I just thought Seresto was a lot cleaner and easier to use, oh how I was wrong.

  90. Hartz drops are just as bad if not worse. They have a terrible reputation! It’s best to go with an oral flea medication like nexgard or bravecto

  91. I don’t know why people are suggesting the chewable flea meds. I haven’t tried them all, but I put my papillon on a monthly chewable, and he started constantly hiding under the table for the first 2 weeks after each time I gave it to him. after the second month I figured it out.

  92. I have used Seresto collars for a few years on 2dogs. Never had problems. I now have them on my cats and they are doing great. I think as with any medication some will fail

  93. ALL flea and tick meds can cause a reaction and seizures. You are putting a toxin in or on your pet. Would you take it? I have seen hartz drops eat through a dogs neck (not a burn). My cat has had foaming at the mouth and confusion after applying frontline and advantage topical. My other 2 cats have never had any problems with topical or collars. You can’t put a hazardous chemical on your pet and think they will react the same. Same as allergies to foods, meds, and environment with humans.

  94. My Lhasa Apsara was on the chewable flea and tick preventive medicine. He had seizures from it. The last one he had was before Christmas last year. It was the worst one he had., He is wearing a Seresto collar now. I hope
    and pray it works for him.

  95. A 3 years and 8 months Irish wolfhound was wearing this collar for several months. A couple of months ago, he started to trip over his right foot regularly. A few days ago he went into cluster seizures on and off for two days, lost the use of his right leg, had a terrible fall and injured his legs and had to be euthanized. The owners do not know for sure that the collar caused this, but they are very suspicious. He had been perfectly healthy prior to this. Irish wolfhounds had very sensitive to many substances that may not bother other breeds.

  96. So, this collar still puts neurotoxins into our dog’s bloodstreams, which I hate. It does it slower and less invasively than oral or topicals, but it’s still neurotoxic ingredients, how else would it kills pests? I have recently put this on my dog because it’s high flea/tick season where we live, but I hate doing it. In the meantime, I give her immune system boosting supplements and bath her weekly to try and keep her as detoxed as possible. It’s so frustrating that most people just give their pets this kind of thing without reading up on what each chemical is and does. At least we should be informed about what we’re allowing into our pet’s bloodstreams/organs and not just say “yay it works”. I hate having this collar on my dog, but I’m going to have to do it until high flea season is over. Still hate it though..there are so many natural preventions, which we normally use the rest of the year. I’d hate to have this stuff in my baby’s sytem for more than a month or so.

  97. My 9 year old Boxer has worn the Seresto collar during 2 different flea seasons prior to this season. I put it on him and 6 days later his eyes are bloodshot and his face is swelling. I have given him a bath and taken the collar off. Will see if the swelling goes down. My other 8 year old Boxer has had no problems with the collar but I will be taking it off of him and looking into the Food Grade Diatomaceous Earth.

  98. Other than an itchy neck occasionally, my large sighthounds had been fine with the Seresto collars for the past 2 years. This year however, within 10 days of wearing the collars, (A) two of the dogs dogs started making dry coughing (hacking) noises… (B) One of the dogs had diarrhea in the evening while showing signs of extreme hind end weakness and did not wake up the next morning. (C) I removed the collar from the second dog, who is sensitive to nothing ever, and she had puss filled sores under her collar…these were not rub makes but chemical burns (D) The third dog also had extreme diarrhea and I removed the collar immediately but no chemical neck burns on her…
    These collars seem to work well on the ticks but can kill anything (this includes your pets) if the particular batch made by Bayer Seresto is overly-strong.
    I believe that there is no quality control at the Bayer factory as similar to Robert’s Winston that died suddenly…my dogs were fine in previous years wearing the collars, but this year the collars had devastating effects and took a beloved friend away from us. My heart goes out to all that have lost their friends or to those who fiends are suffering still!
    Thank you for posting to this site….I never would have suspected the collars had I not seen this and ALL 3 would have likely died a horrible and preventable death.

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