Antifreeze Poisoning in Cats

Ethylene Glycol Poisoning in Cats

Antifreeze poisoning is one of the most common forms of poisoning in small animals, and this is because it is so commonly found in households. Antifreeze poisoning typically happens when antifreeze drips from a car’s radiator, where it is then licked off the ground and ingested by an animal. Your cat may also come into contact with antifreeze that has been added to a toilet bowl. This occurs in homes where the residents will use antifreeze during the cold months to "winterize" their pipes.

Even if you do not take this action in your own home, it is something to be aware of when visiting other homes, or when vacationing at a winter residence.

It is the toxin, ethylene glycol, that makes antifreeze lethal. Ethylene glycol has a sweet taste to it; because of this, an animal will consume the liquid in quantity before the aftertaste becomes apparent and causes it to stop. By then, it is too late. It does not take a significant amount of ethylene glycol to cause fatal damage to the system; less than three ounces, or 88 ml, of antifreeze is sufficient to poison an animal. Antifreeze poisoning affects the brain, liver, and kidneys.

Ethylene glycol is also found in engine coolant and hydraulic brake fluids.

Symptoms of Antifreeze Poisoning in Cats

  • Seizures/convulsions/shaking tremors
  • Fainting, coma

Diagnosis of Antifreeze Poisoning

Treatment of Antifreeze Poisoning in Cats

If you witnessed your cat ingesting the antifreeze, or you suspect it based on the symptoms and possible access to the substance, you will need to immediately encourage your pet to vomit.

For immediate first aid (if you are positive that your pet has ingested this toxic substance), try to induce vomiting with a simple hydrogen peroxide solution of one teaspoon per five pounds of body weight -- with no more than three teaspoons given at once.

This method should only be used if the toxin has been ingested in the previous two hours, and should only be given three times, spaced apart at ten minute intervals. If your pet has not vomited after the third dose, do not use it, or anything further, to try to induce vomiting.

You may want to call your veterinarian before trying to induce vomiting, since it can be dangerous to do with some toxins; some poisons will do more harm coming back through the esophagus than they did going down. Do not use anything stronger than hydrogen peroxide without your veterinarian's assent, and do not induce vomiting unless you are absolutely sure of what your cat has ingested. If your cat has already vomited, do not try to force more vomiting.

A final word, do not induce vomiting if your cat is unconscious, is having trouble breathing, or is exhibiting signs of serious distress or shock. Whether your cat vomits or not, after the initial care, you must rush it to a veterinary facility immediately. Your veterinarian will be able to safely administer antidotes to the poison, such as activated charcoal to prevent further absorption of the toxin, and 4-methylpyrazole, which can treat antifreeze poisoning very effectively if given shortly after consumption.

Your cat may need to be held in intensive care for a short time to observe for and prevent kidney failure.

Living and Management

Cats that have consumed antifreeze in very small quantity may survive, but will develop kidney failure within days of ingestion. Death due to kidney damage is common among animals that have been poisoned by antifreeze.

Prevention of Antifreeze Poisoning

Antifreeze poisoning can be easily avoided by following a few simple precautions:
  1. Keep antifreeze containers tightly closed and stored out of the reach of pets.
  2. Take care not to spill antifreeze, and if it is spilled, ensure that it is immediately and thoroughly cleaned up.
  3. Dispose of used antifreeze containers properly.
  4. Check the radiator of your car regularly, and repair leaks immediately.
  5. Do not allow your cat to wander unattended where there is access to antifreeze: roads, gutters, garages, and driveways, for example.
  1. There are now antifreeze products available that use the safer propylene glycol as an agent, which the American Food and Drug Administration has labeled as non-toxic. Look for antifreeze with this ingredient instead, to keep your pet safer from accidental poisoning.

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This article has been approved by the Veterinarian Board. Reprinted with permission from