Do not ever, EVER use Hartz products on your pets

I am currently in college studying Veterinary Medicine. Hartz products are DANGEROUS. we specifically discussed that in class. They are known for making animals ill, and unfortunately–killing cats. Dogs can tolerate pesticides better than cats (even though it is dangerous for both). Harts flea and tick control products contain pesticides, Deadly for cats, dangerous for dogs. PERIOD. Hartz have many lawsuits against them, and they do need to be shut down. If you have any signs of adverse effects (which seems to always occur with EVERY Hartz products) discontinue use IMMEDIATELY. As a matter of fact, DO NOT USE IT AT ALL. Things that can occur are rash, itching, blisters, bumps, seizures,loss of appetite, fever, vomitting, etc. and even, unfortunately, death. If you need flea and tick control, for your pets sake, please use Frontline. It is the safest product, and Veterinareans number one choice for a reason.

69 thoughts on “Do not ever, EVER use Hartz products on your pets”

  1. I’m confused. I am hearing and reading so many negative comments about this product. I have used it twice now and neither one of my dogs nor our cat has ever had a problem with it. Maybe we are just the lucky few and i now know about the adverse side effects I keep reading about but if the product is so bad why is WalMart selling it? Im very confused. I am simply a pet owner attempting to rid my animals of fleas. Why are my dogs immune?

    I applied the most recent dose yesterday morning and it has now been over 24 hours with zero side effects.

    Any thoughts….


    1. Not all animals will have a reaction from it, however there are cases of animals having a reaction to it even when they used it previously. It is not worth the risk of possibly causing your pet to become ill, distressed, or even dead. They’ve been able to keep their products on the market somehow despite all the cases of animals suffering from it. Don’t ask me why or how. It is common knowledge in the veterinary community that this brand is dangerous but it’s sold over the counter and pet owners have no idea.

    2. It’s hit or miss as to which pets are affected. I had 3 cats, 2 were brothers, and the 3rd was from a different litter.
      I used Hartz flea powder on all of them. The 2 brothers were ok, uneffected, but the 3rd cat wasn’t so lucky.
      My poor Tigger became very sick within about 4-5 hours. Took him to emergency vet hospital. They said all they could do is flush his system & even with that, his chance of survival was very low.
      He died the next day.
      I was so upset, heartbroken & FURIOUS.
      How can they sell products with deadly ingredients????
      They’ve been getting away with it for many years.

        1. Mine, too. I used Hartz Sergeants flea meds on our 9 cats and two large dogs (over 100 lbs.) and they all were SO sick! Two of the cats nearly died.

          Within 45 minutes to an hour after application, one cat had a seizure, one simply fell over. After consulting our vet who all but screamed when she learned that I had used that product, I did the only thing I knew to do — washed all eleven victims thoroughly with blue Dawn dish soap. Used two large containers of cottage cheese in an attempt to further flush their systems.

          It took almost 24 hours for them to come around to normal except the cat that had a seizure. For two more days, he walked with a head tilt and his legs and head looked like they were vibrating. Vet said it was neurological damage. After EIGHT days, he was back to normal.

          Although I immediately contacted Hartz, the representative I spoke with came across as nonchalant and treated the situation as though it were the norm! About three days later, I received a follow up call from a different rep — I returned the two unused flea colors and the empty boxes of flea medication along with my receipt. I received only a refund on the products.

          Horrible, horrible experience!

          PS: No need to think I am an animal hoarder — we live on a farm. 😅😁

        2. I just lost 2 dogs in 2 days. The youngest one first on supposed liver failure, and now today my oldest at 15.5 years of age. My youngest was 13 and very much alive and happy! I’m lost for words right now, something chemically happened to my dogs.

      1. Can you please disclose what symptoms Tigger had? My cat is starting to experience hot, red and slightly blistering skin but I washed the product off about an hour after application and have not seen anymore visible signs of distress but I do not want to miss anything.

        Thank you and I am so sorry about your kitty, I couldn’t imagine.

      2. My cats had the Hartz flea collars put on them less than 24 hours ago, now they have lost the hair on their necks and have painful blisters, I am in tears, I never knew that this company could be so heartless and sell basically poisionous product! How are they getting away with this and what can we do about it? I feel so horrible for my fur babies and very guilty that I put them through this but I am curious with Hartz!!!

    3. Having suffered the effects of toxic chemicals, you won’t know until it’s too late, or you won’t notice at all. You may attribute damage two years from now to age or some disease.

    4. Not every pet will have a reaction but I think enough have that it should be taken off the market. Yes it’s sold at Walmart but so are food brands like “gravy train” and those are horrible for dogs. It’s just the cheaper easier route. It’s worth it to pay more to know you are getting a reputable and quality product.

    5. My friend used 2 of a 3 pack on her cat with no trouble. The 3rd dose almost killed him with seizures.

    6. I unfortunately used this product on my cat 2 days ago and this morning she didn’t wake up I am heart broken and Hartz needs to be shut down I lost a family member because there product the vet even asked if it was this particular brand and said it’s not the first case they have had

    7. For one thing; the author of the original post about NEVER using Hartz products on your pets CLAIMS to be a vet student, but his inability to spell veterinarian and his atrocious grammar seem to make his claims suspicious. The internet is so full of these spurious types of claims; that I would get my information from a more reliable source. Science and medicine will both tell you that ANECDOTAL accounts are not reliable; meaning all of these stories posted by people online. I am sorry if people have lost pets, but blaming it on Hartz without proof is similar to the anti-vaxxers claims that vaccines killed/made autistic/fill in the blank their child. As a healthcare provider myself (people; not animals), I would say: ask a trusted vet. Cause of death in general must be proven by pathology reports, NOT opinions. All I know is, as a lifetime pet owner, my parents always used Hartz products without a problem, and as a suspicious person by nature, I would not be surprised if this rumor wasn’t started as corporate sabotage by the Frontline manufacturers. Long story short: don’t be the idiot who gets all of their “information” from the internet. It is totally unregulated and people can say just about anything they want.

      1. I actually spoke with my veterinarian about using their products on my animals . All three veterinarians at my local clinic adamantly spoke against using their products due to the issues they’ve seen occur with animals Up to and including death . So being that this cake from trained professionals I think I’ll take their word .

    8. Yes your dogs mightbe lucky but not next time. Kidney and liver can only take certain amount of toxins and next time your dogs will be having high degree skin burns and die just like it just happened in Dubai to one of the dog owner. She lost one of her 2 dogs and the second is fighting for life. She used Hartz ‘gentle shampoo’ for puppies!

    9. my cat had seizures from cutters which is basically the same thing as a costed me $450 to keep her alive! Hartz killed my brother’s cat.

  2. Frontline may be safer than Hartz, but it still has the potential to cause similar adverse effects. Frontline claims that it does not get into the bloodstream, but that is not true. Pets with skin problems, such as flea allergy dermatitis, are even more at risk of Frontline getting into their bloodstream, which increases the potential for adverse reactions.

    The Australian government recently completed a review of Frontline due to numerous reports of adverse incidents:

    They are recommending that additional warnings be put on the Frontline label, including not applying it to ‘non-healthy’ skin.

    1. Very true. All pesticide based products are dangerous and damaging t organs mainly to liver and kidney and cause neurological damage. Avoid them at all cost and instead use preventative natural safe products, such as Diatomaceous earth (make sure its FOOD GRADE) or diluted safe for pets essential oils as repellants. Buy Mercola safe products

  3. WHY IS THIS HARTZ product (s) still on the market– I just want to shout out to everyone – DO NOT USE ANY OF THESE PRODUCTS! Our 7 yr old healthy dog had- and is still having a horrible reaction to the flea and tick drops –he scratched until he bled – his skin was raw and he has been miserable for over a week now -how much longer before they are healthy and back to normal??- thanks to your website – we’ve been rinsing him with warm water every day and it has helped -no infection that we noticed and the vet was livid over the reaction…our poor dog has ben whining and just not himself – i feel horrible putting this on him to keep off ticks when we went to the psrk – I’d rather risked having ticks!Please keep us informed – should we take pictures to send to hartz?? We are so angry – they are so irresponsible to not do a massive recall and investigate this!

    1. Wash it off..

      Dont just rinse!
      ALL of it.. more than once. If you already did this.. try some arnica cream from.walgreens for pain. Its all naturl and wont hurt him.

      Rinse for VERY long periods following the washing.. try to keep water cool luke since the chemicals cause burning sensation (you want to avoid water tol warm or even normally warm water).. until the skin has cleared.. and no more sores remain wash w/ a gentle solution w dawn detergent and get everywhere that product went.

      Best of luck

  4. I used hartz flea and tick on both my small dogs. One of them was just so hyper after the use. It was strange, it was a dip. I’m afraid to use it again.

  5. I completely agree with you (to the first comment on here) I have been using this product for quite some time on my dog and have never had any bad side affects happen to him whatsoever…so I am just as confused as you as to why there are so many bad complaints- and if Hartz has such a bad rep, why do stores continue to sell their products???

    1. Stores sell for the money. Don’t care what Happens to our poor fur baby’s…… Poor baby’s! Should be used on the FDA that approved it to be used on cats.

  6. There are adverse side effects with any kind of medication, shampoo, or ANYTHING people! C’mon. Humans have side effects with their medications too. Including death. So should we stop taking medicine too? This is ridiculous.. Just because YOUR dog had a bad reaction doesn’t mean MINE will. We’ve used it for years with no problem on dogs AND cats.

    1. Wash it off..

      Dont just rinse!


      Best of luck

  7. Im in the vet school as well, and learning about this. And you
    are 100% correct. Stores want as much money as they can, so they don’t care if a product is harmful. They only recall products harmful to humans, which is unfair to animal owners.

    1. Stores sell for the money. Don’t care what Happens to our poor fur baby’s…… Poor baby’s! Should be used on the FDA that approved it to be used on cats. Think if you would not put on your skin, why would you think it is Ok to put on your fur baby? I feel so sorry for my poor cat that is now suffering .

  8. Thank you Angela :),

    And for those of you who posted that your pets haven’t gotten a bad reaction…well, it hasn’t happened yet. Before I began studying Veterinary Medicine, I used Hartz flea collar on my dog..first time, he was fine. 2nd time, months later, he got blisters all over his neck, became lethargic, began vomitting, and having diahrea.
    Just because it hasn’t means it hasn’t happened yet. My vet teacher stressed that just because it hasn’t happened yet, it is only a matter of time before it does happen.
    Think about it..would you put pesticides all over your skin?
    When I used it, my hands burned just from touching what makes you think it’s okay to put something unsafe on human skin, to put on your pets skin?
    And like Angela said, they only usually recall products that are harmful to humans. Pets are seen,by law, as “property and luxury items”.
    Go to your vet and get the appropriate medication. Like I said before, don’t use Hartz. Stick to Frontline, Advantix, or Revolution. All medication has a risk of bad side effects, just like human medication (in response to hamishdad). Animals with flea allergy dermatitis should be seen by the veterinarean first.
    Always see your vet first, or get professional advice.

  9. Sysy, they do have recalls on pet products.. Especially food. For someone in the medical field, I would think you would do your research. Also, I’ve used Harts on my dogs for YEARS. If they haven’t had a bad reaction yet, I doubt they are going to. Nothing has ever burned my hands.

  10. I too have had horrific effects on my cats and dog with Hartz products. We contacted our vet over the weekend when we discovered our newborn kittens had fleas- the fleas were irradicated from our home, but unfortunately the person who brought them to us originally came to visit and they’re back. We were advised to bathe mom and babies with Dawn and use a flea comb. Like magic, the fleas died on contact and they are completely flea-free this morning. We also spread food-grade diatomatous earth on the carpets, as this is an edible organic compound. So far, so good. Now I have 4 other adults, 1 older kitten, and 1 elderly dog to bathe. Dawn is an amazing product and extremely effective so far. We purchased the dye-free, hypoallergenic formula which has a very mild scent. I’ll keep you posted.

  11. @ anonymous- Your’re chicken to give your name? Sad. I hope you NEVER have to go through what any of us have experienced because it is absolutely heartbreaking. Maybe you’re one of the very lucky ones. Maybe you’re just a pet owner and NOT a per lover. Our pets are like children for a lot of us, especially those who cannot conceive so watch it with the insensitive comments. Oh, and FYI- I too used Hartz in the past without any issues at all. I spoke with a fantastic woman from the EPA and there is a study going on nation-wide to find out WHY this is happening en masse this year. She told me this is the worst year so far with injury from Hartz products. Do YOUR OWN research before you make a fool of yourself again. No wonder you remain anonymous.

    1. Every one has their own opinion, I’ve used HARTZ products for quite awhile now and this is the first I’m hearing about all this fuckery. Sure, a lot of dogs have had a reaction to it but many probably weren’t paying attention to their animal as they arent going to sit there for 24 hours to watch what the animal does. While you’re sleeping or away you’re pet could be licking/chewing at their coat which they would be ingesting pesticides which is what would cause illnesses/seizures etc. After using animal pest removing liquids you should be making sure youre animal cannot chew or have contact at the areas that pesticides have been placed. I always use cones for the first 24 hours after a flea bath or applying drops. I constantly look through my dogs coat with a comb to see if her skin is having reactions and I’ve never experienced problems before. I’ve been using this product for a little over 3 years. My dog is a 8 year old bridle bullmastiff mixed with pressa canario. She is an elder and never once had a reaction to HARTZ products. I go between HARTZ and ZODIAC. Never had an issue with either of them.

  12. I’ve been using Hartz products for about 13 years now. 0 deaths of my animals. I don’t treat my animals for ticks or fleas with medication. It’s to easy to take the time to care for them without medicines. I use dewormer on my puppies each time our bitch has a litter. So far 17 puppies and 0 deaths. As for the cat side, If your cat weighs less then 2 pounds when using dewormer then it serves you right it dies. Like any medicine, if you fail to follow the instruction then you reap the consequences. In the end, if you were to lazy to take them to the vet because it was cheaper then that’s on you not Hartz, if you don’t know what is what with worms then don’t try to play vet.

    -23 years Veterinarian. I would never recommend someone try diagnose worms. I would always tell people to go with frontline if they need to take the easy way out of tick/flea removal.

  13. I used the flea drops and my lovely, friendly, happy, cal cat started running around and hiding, she had no appetite, her fur turned spiky and oiled and she was very unhappy. After looking it up, I quickly realized that she could be hurt even further by this and washed her with a wet soapy washcloth (followed by a dry one) and now she’s her friendly self again! She’s even eating properly, and seems happier, (though the damn stuff didn’t even get rid of the fleas, as she’s still itching) I wouldn’t trust his toxic goo for use on any of my pets ever again, and I suggest you upgrade, even if it means you have to downsize from salmon to tuna for a while. 🙂

  14. i used half a tube of hartz ultra gaurd flea drops on my 1 yr. old chihuhua today at 330 and when i got home from work i noticed she was being really strange. she is really wobbley her head keeps wobbling and she cant sit up and her eyes are all squitting and her ears are layed back. i gave her a bath with dawn soap and she is hust lifeless .now all i can do is keep watching her and pray she will still be here with me tomorrow. she is my baby i dont know what i will do if this kills her. please god i am begging you please dont let her die please

  15. To the few who use and think it is safe…ask your vet. Any reputable vet will tell you NEVER use Hartz. Your idiots who are just pet owners and not pet lovers especially the breeder.

  16. Omg my dog had 2 seizures just 3 days after putting a flea collar on him.. I don’t know why this products are still on the market. Wish I would had seen this website sooner. . Animal murders that’s all you can call them…

  17. I applied Hartz spray on my healthy 8 yrs old dog and he passed away 6 days after…renal failure!! I don’t understand why those products are still on the shelves!!😡😡.

  18. I’ve used HARTZ products on my cat’s before, and didn’t have a problem. Only once my cat started going crazy. It might have been she had flea’s and that treatment made the fleas go crazy. She went bonkers after treatment, but survived. I just used it again, hope I didn’t make a mistake. I do know that vet’s are ridiculous in treating your pet’s. So they say over the counter don’t work good, come to us, and will charge you put the wadzoo for treatment of your pet’s when the economy of bad economics gets so bad a lot of these pet’s are left to fend for themselves. But of course pet doctors got ridiculous. I understand they haft to make a living. But to rip people off. Like my friend taken his sick little dog to the vet. Then they come back and told us it had septic. Then they came back and told us it died. Then they charged him $500 and they barely did anything. That’s a rip off, at first wanted to charge him thousands of dollars to do surgery. His dog was apparently gonna die anyways. Bunch of crap. They don’t care about your damn pet, they care more about $$$$$$$$$.

    1. As someone that was a vet tech, and no longer is, I do apologize for that situation. The truth is, vets are a business, but they actually make very little money. Since humans have insurance, you dont notice the unbelievably high fees. People typically do not buy insurance for their pets and insurance for pets is not the best, so fees seem much higher than they really are. They are a fraction of the cost of human medicine. Vets and techs make very little money. Vets might spend 500k on school and only make 60-90k. Thats even pushing it. To be a vet or tech, you really have to love it. Theres a reason why the suicide rate is so high (constant blame for pets death, consistant debt, euthanasia, ect). Over the counter pet medications and products are NOT regulated like human medications. Many are unsafe and ineffective (like hartz!!). Products sold through vets are more so proven safe and effective. We only recommend these products to keep your pet safe. There is always going to be an inflation of costs, but thats standard. For example, when my grandmother passed, we received a $2000 charge from the funeral home simply because we chose them. EVERYTHING ELSE had its own charge (and i mean every last thing). Its the only way they will stay afloat. This is why vets might charge fees such as a physical exam fee and other fees that dont seem “fair”. They may have done a lot more in the back then you know. You might argue that they should have warned you, but when its an emergency, you have to make calls quick.

    2. Um wow. You don’t have to go to the vet to get a decent flea and tick treatment. It’s called advantage or Frontline. Yes it costs a bit more but is your animal worth it? If not you may as well just not own animals because yes they can get expensive and if a person isn’t prepared for that they shouldn’t own one to begin with.

  19. Im a former vet tech. We had multiple animals come in seizuring and near dead after applying hartz. Recently, I advised my coworker not to use it. She used it anyway (since it was cheap) and her cat died within a day. Many people argue that they have used it without problem. Not ALL animals will react this badly, but the risk is so high and the product is so ineffective that it is useless to use. Also, ALL flea shampoos are dangerous and flea collars are ineffective. Please use advantage or frontline (dont let them ingest it) or get something like revolution from your vet.

  20. Cause the stores get paid for selling their products, everyone should start a petion on harz taking their products out of the stores and off the product line

  21. I’m Donalyn I have 4 cats I put the hartz ultra guard flea collar on them and Midnight one of the two kittens who will be a year on the 19th had open sores and lost all her fur we didn’t think anything of it until she kept getting open wounds now her mother Mittens became very sensitive the grains in the cat food but her coordination is way out of wack she keeps falling and a guy in California used the Hartz drops and three days later signs of issues he took his dog to the vet and the vet said it had to do with the hartz drops his dog Duffy died at the vet so he called the hartz company their denying that their responsible

    1. Cats aren’t supposed to eat grains. Only real meat/fish, and some added vitamins. Please stop giving Mittens and the rest of your cats grains.

  22. We applied the hart’s product to our cat and he has a huge patch of fur missing with a bloody irritation on his neck, he vomited and his breathing is weird. We used dish soap to take as much of the product off and applied cream to help with the irritation. Now we just hope that he will be fine. He has been meowing a lot during the night which is loud. He has been drinking a lot of water since we gave him the treatment. He is nearly 10 years old and we aren’t ready to say goodbye to our little man. He practically a watch dog in our house as he guards the house and when someone ring the doorbell he runs to the front door window.

  23. I cant believe that 9 years later, this is still happening. My heart goes out to all who have lost or suffered. Those of you who have not had issues, you are the lucky ones and I truly hope you never do, as none deserve to go through this. For the sake of your pets, I urge you consider other options.

  24. I lost my baby girl several years ago after using this product. I did not know it would harm her and naively believed it wouldn’t be sold if it was known to kill animals. As my vet later explained “Medicine for animals are not highly regulated. Think about how many medicines pharmaceutical companies put out there that are killing people. How much do you think they are caring about pets dying especially when they are making so much money off the product?”
    It’s enraging and disgusting.

  25. Well not everyone can afford to buy Frontline Plus, Pet Armour,Advange,Advantax, Seresto Flea & Tick Collar,Capstar,and other oral medicines it’s just not possible for some. Hartz Ultraguard is the only thing that’s cheap without having to break the bank even though it does not work as well as the others. Never really had any health problems with using this product on my pets. I think the problem is people use the medicine wrong either the wrong dose size or on the wrong species which would cause death.

    1. Well then a person Shouldn’t own a pet. We have 7 cats and I would NEVER put this hartz crap on them to save a buck. I mean think about it. You can go to Walmart and buy this garbage for 7 bucks or so for 3 months for 1 cat. Why do you think that is? It’s because it’s crap and they know it is and is not effective anyway. You think everyone who lost a pet due to this product used it incorrectly? Doubt it. This has been a huge problem for many many years. If you own an animal you need to be prepared to spend money on them if they get worms or fleas or any kind of issue. If someone can’t care for their animals properly they SHOULDN’T have one. Just like you shouldn’t have kids if you can’t feed and care for them without going on welfare. There is a difference in a pet owner and a pet lover. I love my animals and they are part of the family and I would NEVER cheap out on a product like this that could potentially kill any of my babies. I’m not saying everyone that has given their animals this crap don’t love them, they are just uneducated. It’s the ones that know hartz track record and the lawsuits and ALL the animals that have died and still continue to use it just to save a buck.

    2. I agree with Chris. If you don’t have the funds, DON’T GET A PET. I don’t care what your excuse is. Your pets are not just a toy, they are living, breathing creatures who rely on your for their health and safety. Shame on you for giving your pets mediocre and dangerous medicine just because you can’t afford a couple bucks more on something that won’t legit kill them. Stop having pets.

  26. Ok so I have 2 cats and I just medicated them a few days ago and I say on one of my kitties a small bald spot where the medication was aplied and then I looked a little closer and saw about an inch and a half in diameter scabbing and red spots and after reading up on hertz products I’m starting to worry, I just rinsed out her fur for about 10 mind and decided to give her a bath. She has been acting completely normal aside from what looks almost like chemical burns. Do u think she is in the clear? Is she going to be ok? Should I worry or am I over reacting? I have used hurts on her before and she has never had a reaction like this before.

  27. Maybe you should stop and think for a moment, Chris? Life happens to people! Unfortunately some just do not have the same choices and or knowledge in front of them all of the time; like you apparently do. From reading your comment, you seem to know it all and have every resource available at you’re whim. Do you really believe anyone would knowingly put their animals wellbeing at risk to save a dollar. What tells someone standing in Walmart as in your example, they should or shouldn’t purchase one brand over another? They all have similar claims. Some of the active ingredients are the same, albeit usually in different percentages, and the typical pet owner doesn’t know why or how they work. Price doesn’t indicate the risk of serious injury or death of an animal despite what you may think. What tells someone that $7 or $50 or more is the correct price for ridding pets of fleas and other critters? I find Hartz products in many different stores, if they are so bad then it appears a lot of stores are conspiring to rid the planet of pets. Until seeing this site, I haven’t ever heard of the “Hartz track record” as you put it.

    1. “Life happens to people!” And your pet should be sacrificed just because you decided to get the cheapest (and most dangerous) medicine at Walmart? Save your excuses. If you can’t pay for the well-being of a LIVING, BREATHING CREATURE, then guess what? Don’t have one. Simple as that. I’m sure they’d rather live with another family rather than be treated as a toy just because their owners want to save a buck.

  28. Is everyone missing the point here? The illnesses are caused mainly by ingesting the product from their coats,
    If you actually follow the directions, it tells you precisely the one spot to apply so ingestion is impossible.

  29. My wife applied flea drops to all 7 of our dogs. 2 of the puppies are now ill. Throwing up, diarrhea. We are treating them with pedialyte and are under a strict watch! As soon as we notice they are keeping the fluids down we’ll start force feeding blended boiled chicken and rice

  30. i just used haertz on my golden he is having a bad reaction heavy panting and does not want to move off his bed he seems dissoriented never use this product again

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