Why do dogs and cats drink antifreeze and how does it kill them?

This is one of the most common forms of poisoning seen in dogs and cats. It usually happens when the antifreeze drips from your vehicle’s radiator forming a puddle on the garage floor or driveway. The active ingredient in antifreeze is ethylene glycol a syrupy liquid that seems almost addictive to some pets. You must take special care if you change your antifreeze yourself, since pets can get into containers left open or spilled. It is possible for a cat to poison itself by walking through a puddle then licking its paws. As little as five tablespoons of commercial antifreeze is enough to kill a medium sized dog. If you see or suspect your pet has ingested antifreeze you should make it vomit, by giving it a teaspoonful of hydrogen peroxide per five pounds of body weight, but not more than three teaspoonfuls at a time. If it vomits or not, take it to your veterinarian as quickly as possible and explain what you think has happened. If your pet has already vomited, do not try to make it vomit more. Do not try to induce vomiting if the pet is showing signs of distress, shock, difficult breathing or is unconscious.

Ethylene glycol is also an ingredient in some liquid rust-inhibitors, incorporated in solar collectors, used in many chemical manufacturing processes and can be found in a variety of household products. Check the labels! To be most effective, your veterinarian must administer treatment within three to eight hours. Ethylene glycol is actually an alcohol converted, by enzymes in the liver, particularly alcohol dehydrogenase, into oxalic acid. The oxalic acid combines with calcium in the blood to form calcium oxalate crystals that block the nephrons in the kidneys and result in kidney failure.

Since ethylene glycol is an alcohol, the early signs of poisoning resemble drunkenness; euphoria and/or delirium, wobbly gait, uncoordinated movements, nausea as evidenced by excessive salivation, lip smacking, dry heaving, and vomiting. This phase can persist for about six hours and the animal may appear to be better, not so! If untreated the signs progress to excessive urination, diarrhea, rapid heart rate, depression, weakness and eventually into fainting, tremors, convulsive seizures, and coma, all signs of kidney failure.

If you arrive at the animal hospital in time and give a history of your pet ingesting antifreeze, or your veterinarian runs appropriate tests and makes the diagnosis, before signs of kidney failure occur, there is a good chance your pet will be saved. Treatment involves the induction of vomiting. Using activated charcoal to bind any ethylene glycol still in the digestive tract is not effective, but may be indicated when other toxins are suspected. Since 1996, your veterinarian has had access to fomepizole (Antizol-Vet). This drug is an effective antidote, if administered intravenously before kidney damage occurs. Back in the olden days, we used grain alcohol as an antidote, significantly less expensive than fomepizole. Alcohol dehydrogenase has about 100 times the affinity for grain alcohol than it does for ethylene glycol. When used as an antidote the liver metabolizes less ethylene glycol and fewer oxalate crystals form. Depending upon the severity of kidney damage it still might be possible to save your pet with aggressive fluid therapy to flush the kidneys, and other supportive treatment. Some specialty practices may be equipped to provide kidney (renal) dialysis. You do not want to know how much a kidney transplant will cost, but it is possible, in both dogs and cats, in specialized centers with the necessary equipment and experience.

20 thoughts on “Why do dogs and cats drink antifreeze and how does it kill them?

  1. Thurman Jones

    By no means do I condone cruelty to animals, but I’m also not that sympathetic. Pet owners should not allow their pets to simply roam around. I’ve had nothing but bad experiences with cats in my garden and destroying plants and shrubs. If some owners were more considerate, maybe there would be less issues all around!!

    1. Thanks for taking the time to write. In this day and age it is more common for pet owners to keep their animals contained than it was when I graduated from veterinary school in 1960. I hope you did not arrive at my website by making one of the many inquiries about how to kill cats or dogs with antifreeze. Poisoning any animal with antifreeze would be very cruel and I hope illegal in most communities. It should invite prosecution for animal cruelty.

  2. sandra

    My cat has been killed with a neighbour using anti freeze….its a horrible and painful death and my cat suffered so much, please dont use this,Iam haunte by my cats last 24 hours and the agony it suffered.

  3. John

    So antifreeze is a painful death and probably considered animal cruelty.

    But heres my situation… This male cat keeps breaking into my house through windows or any means it can and pisses everywhere.
    If I leave the antifreeze say in my house and the cat gets it, is that still considered animal cruelty?

    1. Absolutely, please don’t do this. I’m certain there is some sort of animal control office in your area. Please contact them and they will help you capture this pest or identify his owner and solve this problem for you without resorting to a very inhumane method.

      1. John

        I’ll see if the rspca will take it but it isn’t a stray.
        I know who the owners are and i already know how this will play out.
        These people won’t care what the cat does but i will give them a choice to soft the cat out or i won’t have any choice but to do it myself.

        I can’t have this cat destroying my place.

      2. If you know who the owners are I would think you have legal recourse. Their animal cannot be allowed to destroy your property. Perhaps the police can help. At the least they should be forced to keep this animal confined to their own property.

  4. Sandie

    Cats don’t like water, when the animal is in your house just use a water pistol and squirt it at the cat , and scream at it, the fear will make the cat run and not return , why would anyone want to take the last breath from any living creature ??? Yes there annoying creatures and yes there are to many being bred, and they kill birds as a animal they are killers, but a painful death ??? would you like to leave this earth RIDDLED IN PAIN !!!!

  5. serena

    I think even the idea of putting anti freeze down in or out of your house with the intention of killing the cat is discusting. I believe you are angry with the cat but if it’s owners are as bad as you say then he might be stressed and looking for an escape and he chose you…..They are very clean animals and would normally toilet out of the home or in a clean litter tray….please consider your actions it is not the fault of the cat…It is the owner….

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  7. Charlene

    We just found out that our 2 year old tuxedo cat is in kidney failure. We got him about a year ago and seemed healthy. He was a stray but was taken in by some guys at a diesel shop and we were wondering if maybe he had gotten in to some antifreeze and has been slowly damaging his kidneys. Is this possible or is it probably something else.

    1. Hi Charlene; it is indeed possible antifreeze poisoning is the cause of the kidney failure. Unfortunately you probably won’t know for certain unless he dies and a necropsy shows oxalate crystals in the kidney tubules. I hope you are having him treated by your veterinarian and he is making progress towards recovery.

  8. Kevin

    Im surronded by 11ELEVEN barking dogs.
    Ive talked to neighbors. Their answers range from “sorry” to “dogs bark, man”.
    I have written animal control. I took a day off from work to speak to animal control.
    Over a month later, 11 ,ELEVEN dogs STILL barking.
    I do not have $ to move. But I do have $ for antifreeze and some dig treats!

    1. Please don’t do this. Aside from being responsible for horrible deaths you will probably be charged with animal cruelty, maybe worse and will face a multitude of legal problems not to mention the wrath of your neighbors. Your threat is in the open for all to see.

    2. Sumpter

      Kevin- Similar problem at our house. Check your county Noise disturbance laws. Call the cops (non-emergency line) and report it. At midnight or later. Each time you call the cops will go out. do this every other day for a week to 10 days and cops will tell them to keep the dogs quiet or they will fine them. In our county we didn’t have to leave our name/number. and the dogs are actually being taken of now! Shocker!

  9. Ann

    Hi I am a cat owner I have just spent the most horrific week end keep my two cats alive after someone thought it was good idea to give my cats antifreeze 😡😡😡. I actually thought they were going to die , I was syringe feeding them mixture of boiled water with sugar and pinch salt .they were a pity full pair took them to vets and they told me what it was 😡😡 how anyone can do this to a poor defensive animal I will never no . My vet said she was very surprised that they had not died , obviously my force feeding them with syringes kept them alive 😻😻😻. So to the person who done this you reep what you sow 🙀😾😾hope karma comes to visit you soon enough. I am £100 for vet fees but I still have my cats 😻

    1. Gillian O'Neill

      I’m so sorry for your terrible experience but so glad that your cats survived. My mams cat wasn’t so lucky … We got him to the vet but it was too late and had to be put to sleep. It was heartbreaking. A couple of weeks later we heard of two more cats dying with the same poisoning and that several people were starting to suspect somebody who lives in the area doing it on purpose. Hard to prove because of course the guy will obviously deny it. I just don’t know how they can live with themselves….their hearts must be black and totally unfeeling. God bless you and your beautiful fur babies…may you all live long and happy lives xx

  10. Randy Cefalu

    This would clearly be a much less of an issue if people kept their cats indoors and away from their garages. Our cats do not have access to the garage, plus we never let them out, except for on the porch. Don’t give your cruel, grinchy and pathetic neighbor/s a chance to poison your babies.

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