Five years ago, my dog nearly died from a severe adverse reaction (grand mal seizures) to an over-the-counter flea control product
In the last 5 years, over 126,000 people have visited my website, many of whom found it by searching for information on adverse reactions to flea control products for pets. I have received hundreds of emails (which are posted on my website) from people whose pets became sick or died after using these pesticide products.

I'm a licensed veterinary technician, and have put in many a night at an Animal ER/ICU...I cannot warn people enough to STEER CLEAR from ALL over the counter spot-on flea products...especially with cats (not that dogs can't be harmed by them). Worse yet, never, ever, EVER put an over the counter dog flea product on a cat. I have seen hair loss (minor) and convulsions (major)...and worse.
At the very least this stuff is ineffective.
Unfortunately, it can also kill.
I know.
I've seen it.
And James, I am so sorry about your dog. Thank you for turning an awful situation into the kind of action that has probably saved many lives.

I just put this stuff on my cat tonight and it made her start spitting like crazy, I'm assuming she licked some of it off of her skin. Needless to say, I threw her into the tub immediately. I'd rather suffer the scratches than know that I harmed my poor pet. :( I hope your cats came through the spots on their skin okay,...

i'm sorry that i had to learn the hard way...my mom thought she was doing something good for max (my kitten...i call him my son) but it turned out to be near fatal. he still is not in the clear, but if he makes it through tonight he should be ok. but after the seizures he suffered corical blindness that may or may not go away. in max's case it seems to be going away, but like i said, he's so up and down that we still arn't sure that he's gonna be ok. i would think that this would have to be illegal in some way, but i guess not if it's somewhere on the package..i just hope that more people check sites like this before subjecting their pets to this terrible product!

We just recently applied the zodiac flea treatment to both of our dogs (a schnoodle and a bichon frise) and within 24 hours they were both crying out loud and unable to sleep or go more than 30 seconds without twitching and trying to get at their backs. It is awful to watch them go through this we have tried to wash it off and have given oatmeal baths and tried to give benadryl and neither seem to work too well. We are using a hotspot spray for them now and it seems to provide releif for an hour or so and then we have to reapply it. I dont think i would risk giving any future pets this stuff :(

I just bought this product and, since I hadn't heard of it before, did a Google search for reviews. AM I EVER GLAD THAT I DID!!
Between what I've read here and on amazon.com, it's going straight back to the store where I bought it, where I will recommend to the staff that their management look into whether they should be carrying it.
For the sake of my little munchkins (and my own peace of mind), thank the gods for the Internet!
To James and those who commented, I hope your pets are well and recovered. Thanks for sharing your experiences to prevent others from repeating them.

Three weeks ago we applied Zodiac Spot-on for cats for our 5-month old kitten. We read the label; we had the right product for her age and weight. She was dead eight days later. Her symptoms after treating her: first general lethargy, then loss of appetite, then difficulty breathing and semi-paralysis of her hindquarters. I don't know if it was the Zodiac or the severity of the fleas or both. It's no fun watching your pet suffer or having to tell your young children that their pet is dead. A hard lesson learned; when we're ready for another pet, we will use a vet in the future.

Are you kidding? Several times in very large bold RED type, you are warned "do not use this product on CATS!!!" It's stated everywhere on the packaging. I used this on my dog and when I was reading the instructions (something you might have considered) I was suprised by the number of warnings directed toward cat owners. You wrote this in May and I am writing in October. I find it difficult to believe that Wellmark has changed their packaging and warnings in the last five months. This sounds like another case of a human who can't follow simple instructions and then wants to blame anybody and everybody else for their own shortcomings. DO NOT USE THIS PRODUCT ON CATS!!!
And no, I don't work for Wellmark, or any other pet industry company. I am just a dog owner who can read simple instructions.

Just a comment to the person posting October 3, 2007 about humans who can't follow simple instructions. There just so happens to be TWO Zodiac products specifically made for cats. It's called Spot On Plus Flea & Tick Control for Cats. It even has a Cat shaped applicator. I know because I have the packaging sitting right in front of me as I read these heart-breaking comments about people losing their pets. This product is going right back to the store. How sad that this person posting such an insensitive remark doesn't get his facts straight before attacking these poor people that lost a true member of their family.

Help! We have had a flea infestation in our home and cars. Our lab got fleas about a month ago, so we put him on Frontline but in the meantime fleas got in the house and somehow transported themselves into the car. We first tried a natural product powder in both car and home..this did not work and smell awful. Then we tried a Zodiak carpet and apholstry spray for fleas and ticks. It smelled better but ever since then, my husband and I can't stop itching and feel like we are getting bitten. We called orik pest controll and had them spray and bomb our house and still we itch in the car and feel like we are going crazy. Has anyone had this happen or do you know if this stuff can cause such terrible pain and itching? What should we do? We thought we might have scabies and have also thrown out our mattress and are sleeping on our couch (itching got worse at night). HElp!!!

Go to Topix Scabies Forum. There is alot of good information on there to beat these biting mites.

This does not apply only to OTC products. I have seen terrible reactions, hair loss, bleeding from Revolution.

Get rid of the carpeting and other places fleas hide. You can get rid of fleas without resorting to these systemics. Who knows what else may come up about these products in the future.

It is not true that all cats, even outdoor cats, have fleas. Ditto with dogs.

Please email Animal Poison Control Center [napcc at aspca.org] and cc in [conrel at wellmarkint.com] to make them aware of what's going on. I did, I emailed ASPCA told them that the "ZODIAC SPOT ON Flea Control for Cats and Kittens" is extremely dangerous to cats. I have three indoor cats who recently picked up fleas, so I bought "ZODIAC SPOT ON Flea Control for Cats and Kittens" and applied on their back between their shoulder blades, I followed the exact steps and precautions said on the box.

My three cats' back now have bald spots between their shoulder blades, look like it had been burnt; it is so red and swell. Two of my cats' skins are red and extremely dry; they always try to scratch it, I had to put sweaters on them to stop them scratching on the spots. My third cat actually has infection on the spot, not sure because she scratched 'til it bleed or the solution actually caused the bleed.

My vet told me never trust any OTC products.

Thank you all for sharing this.

Thank you for the article - - it may have saved my cat's life today. I have used Zodiac flea treatments in the past, and no harm has come to our pets. Yesterday morning, I treated all three cats with Zodiac. Today, one of my cats came in from the rain and was shaking uncontrollably. At first, I thought he was simply cold. When the shaking didn't stop after 45 minutes, I went on-line, looking for answers, thinking that maybe he had developed some type of muscle condition. I never thought that I might have poisoned him by using an OTC flea treatment. He is now at the vet's, and they expect him to make a full recovery.

About 7 years ago I bought Hartz brand spot flea killer . It was not formulated for petite weight cats. It poisoned her, she had severe muscle spasms, clouded eyes and drool. She took off out the door and returned the next morning in such an awful state we had her put to sleep. The Vet said it was either a mistake in the product packaging or a toxic dose. I still have guilt for hurting her. Her brother survived her but was ill and put to sleep a year later after losing all his teeth and had lumps under his fur. she was 5 he was 6.

This is why I only use Capstar on my critters. I don't and never will trust any of the claims/promises of the chemical companies that make the stuff.

I'm not saying I wouldn't recommend more expensive brands sold by your vet...

but Spot On worked for my dog and cat, and neither had any sensitivity problem. Not even my dog, who has bad allergies and extremely sensitive skin.

and I'm not saying it doesn't happen...its just that products like Revolution, Advantage, Frontline, can all cause the same kind of problems.

There are all these posts because people who use the product and have no problems will have no reason to seek out further information on problems with the product. Thus, the information is biased towards owners who had a bad experience with the stuff (which is unfortunate and its good to know about risks! they just all have risks)

Spot on is fine with me every other month or so, but as a side note i just switched to Comfortis and i love it. it is taken orally, kills all fleas on dogs within about 4 hours, and is good for a month. so if your dog already has fleas, try this one...the impact is immediate! they do not currently have a feline version, or at least not that i am aware of.

All medicin

My sweet cat baby Opie Taylordied this morning, I found him dead in the kitchen, I applied this on saturday, and later that night washed it offi. Yesterday, he was tired, but he wast eating, he did have some problem with his back legs. This morning I found my baby dead. I killed him with this stuff because I found a flea. Nothing will bring my baby back. I have no children, this was my child.

I too tried this because I could not afford the "good stuff" and now I have 3 sick dogs. One I have to give Imodium to for his severe diarrhea and my 2 chihuahua's have diarrhea now. This stuff is dangerous and should be taken off the market soon. What can we do to get it off the shelves soon before more animals die??????

You can get Advantage, Frontline and Revolution Blue from killfleaz.com without a prescription. It takes about a week for shipping from Australia, but they are authentic products and it costs about $6 for shippping.

I have 4 cats and Spot-On doesn't work at all. They are just indoor cats; and spot on didn't even work. I can't imagine putting it on an outdoor cat and hoping it would work.

Well, I used Frontline (from Vet) on my cat with no bad or good results. The cat wasn't sick and the fleas were happy as can be (not one of them died from the Frontline). I have also used Hartz Ultra Guard Plus (OTC from Walmart) and got better results. Dead fleas and a live cat.

Moral of the story:
For every person screaming about how terrible this "poison" is, there are at least ten more who have no complaints (so you won't usually see them posting here). ANY, and I repeat, ANY flea medication can have harmful effects, so keep that in mind.

I'm not trying to minimalize the fact that some people have had terrible things happen to their beloved pets. Really, I'm not. I'm just trying to point to the fact that for some of us those so called "safe" medications, that you get from a vet, don't always work. And those so called "poisonous" meds, that you can buy OTC, sometimes are the only ones that actually work for some of us.

Last week, my cat of 14 years died of what I thought was just old age. This morning another one of my cats is dead and the only commonality is the Zoidac Spot On Flea Control. I did not use full strength on either cat and did not use any on the third cat. So far the third cat is doing fine....so far. Just an observation....

About a month ago, I brought home a stray (and filthy!!) dog. I found his owners the next day, but about 3 weeks later, my house became infested with fleas!!! We bought some Zodiac flea spray. First, we only sprayed upstairs. Before spraying on the main floor, I decided I'd better put my rabbit (who lived on the main floor) into the garage for a night or two. After 3 nights, and EVERY window in the house being open for that time, we brought the rabbit back in (in his cage). The next night, he started convulsing, lying face first in his litter box and the corner of his cage. We rushed him to my vet (who specializes in exotic animals), where he spent 4 days on IV fluids, getting calcium shots, Vitamin K shots, daily blood tests, etc. On the second day at the vet's, he became completely paralyzed. We visisted him every day. On the fourth day, while I was visiting him, he passed away. He was only 2 years old - my other rabbit passed away about 4 months ago at the age of 10 years.

My vet now advised me that had I asked her first, there is a safe product to use with pets in the home. I believe it's something like "Siphanol?"

PLEEEEEASE, everyone, speak to your vet and take EVERY precaution, no matter what, when using these kinds of products. I will NEVER, EVER forgive myself for what I did to my rabbit.

I had finally got to bring home my dog that had been living with my in laws and to my surprise he had fleas, so needless to say so did my 4 cats and other dog. Since we had to treat 6 animals we went with the zodiac and about a day or two later I swear there were 100% more fleas than to begin with. My dogs have been going out of there minds can't sit still so far my cats seem fine except for still having the fleas. I am so glad I found this because since the fleas weren't gone, I was going to treat them again. Even though it would be too early, I couldn't bare to seem them so miserable. I too have notice my whole family feeling itchy too but I believe that has something to do with how much the fleas have multiplied. It was like food for them. Usually you don't see the fleas, you can actually see them walking all over the animals it is crazy! I know that some people have used it and have no problem. I have 4 cats and 2 dogs and it didn't work one bit on any of them,infact it made it worse. I will never being buying this again!!! Even if something happens lets say in a day or even a couple of hours, bathing the animal isn't going to do anything because the product is in the bloodstream by then. Anything that is topical on animals and us seeps into our skin. Have you ever heard people say make sure you can eat what you put on your skin? That makes sense! There are times that something is needed that surely you can't eat. For example ,lice shampoo, which is completely toxic and I am sure there has to be some bad side effects with that stuff. Something like this where they know there is some side effects shouldn't be used unless they have an antidoate for the side effects. Even though there are some who use it there really seems to be a large % of people who use it and it don't work example me 6 animals 4 cats and 2 dogs and it didn't work on not one of them well it worked by feeding the fleas!!
Not always but when there is a medication that causes problems severe enough to cause death it usually gets zapped off the shelves or the doc isn't suppose to prescribe it anymore. I'm sure you've seen on Tv the commericals about meds and how you can contact them and get money for whatever has happened. Well, to alot of people thier pets are more than just a pet we take care of them as if they are our children. But something like this is just whatever ,it shouldn't be like this all those people who have suffered and spent money on hopes of curing thier animals should be incompensated for it. There should be some way for us to control this. I have four children and 6 animals and don't have money to spend on stuff that doesn't work and now I have to spend more money that I don't have. The company sure have a money back guarentee on it but they already know it doesn't work! Thanks to all that have made this info avaiable if it wasn't for you I would have treated my animals again and god only knows what would have happen! I hope everyones animals are ok and bless all the little ones in heaven. With all the rotten in the world this is the last thing we need animals dying because people are trying to make them comfortable :( Jen

I am SO angry. My poor cat is going through the same thing as writting in the article, and I applied this GARBAGE over 1 month ago. I am sorry to everyone for their losses of their animals.