Antifreeze poisoning in pets happens when a dog or cat licks up ethylene glycol, the sweet-tasting chemical in most car antifreeze. A tiny amount can cause fatal kidney failure, and treatment only works if it starts within hours. If you think your pet has swallowed any, go to a vet now, even if they seem fine.

This is the time of year it happens most. Merck's Veterinary Manual says that in colder climates, most cases occur in fall, winter and early spring, when people top up radiators and spray de-icer on windshields.

What is antifreeze poisoning?

Most automotive antifreeze is based on ethylene glycol. VCA Animal Hospitals describes it as a sweet-tasting, odorless liquid with "a very narrow margin of safety." PetMD says car antifreeze is typically 50 to 100% ethylene glycol.

Once swallowed, the liver turns it into toxic byproducts, Merck explains, and the ASPCA says it affects the nervous system and the kidneys.

The sweet taste is part of the problem. Dogs are drawn to it. Cats can't taste sweetness the way we do, according to Cats Protection, but they're still tempted, and they can swallow it just by grooming a spill off their paws or fur.

How much antifreeze is toxic to a dog or cat?

Very little. Merck's Veterinary Manual puts a dangerous amount at only 3 to 4 teaspoons for a dog and 1 to 2 teaspoons for a cat. The Humane Society Legislative Fund says one teaspoon can kill an average-sized cat.

That's a few licks from a puddle under a car. There is no safe amount, so treat any exposure as an emergency.

Where pets find antifreeze

The obvious place is the driveway or garage: a leaking radiator, a drip under a parked car, an open bottle on a shelf. But ethylene glycol turns up in more places than most people realize. Sources including the ASPCA, VCA, PDSA and Merck list:

  • Car antifreeze and radiator coolant
  • Windshield de-icers and some screen wash
  • Brake fluid and some motor oils
  • Toilet antifreeze used to winterize holiday homes and RVs
  • Snow globes
  • Some paints, wood stains, inks and printer cartridges
  • The bases of portable basketball hoops
  • Ornamental water features, where diluted antifreeze is sometimes added to protect the pump (the British Veterinary Association links some cat cases to this)

PDSA adds a sneaky one: rainwater that collects in old, empty antifreeze containers.

Signs of antifreeze poisoning in dogs and cats

Signs come in stages. The Pet Poison Helpline describes three:

Stage 1 (30 minutes to 12 hours). Your pet looks drunk. Watch for wobbling or stumbling, drooling, vomiting, seizures, and drinking and peeing a lot.

Stage 2 (12 to 24 hours). The signs may seem to ease. This is the dangerous part. The kidneys are being damaged even though your pet looks better. Merck notes this brief "recovery" is mainly seen in dogs.

Stage 3 (kidney failure). In cats this can start 12 to 24 hours after drinking antifreeze. In dogs it usually comes at 36 to 72 hours. Signs include not eating, lethargy, vomiting, mouth ulcers, fast breathing, seizures and coma.

Sources don't fully agree on timing. The RSPCA says kidney signs can take two to three days to show in cats, while Merck and the Pet Poison Helpline say 12 to 24 hours. The lesson is the same either way: by the time it's obvious, it's very late.

What to do if your pet drinks antifreeze

Go to a vet or emergency clinic straight away. Don't wait for signs. The RSPCA's advice is simply: never "watch and wait."

Speed changes the outcome. The Pet Poison Helpline says treatment should start within 8 to 12 hours for dogs and within 3 hours for cats, and that delays sharply cut survival. Cats Protection gives cats a slightly longer window, up to 8 hours, but VCA warns that even a few hours' delay usually costs a cat its life. Once kidney failure has set in, the outlook is very poor.

On the way:

  • Call ahead so the clinic can get ready.
  • Bring the bottle or label if you know what your pet got into. Vets can act faster when they know the product.
  • Don't try home remedies. Leave treatment to your vet.

Not sure if your pet was exposed? Call a pet poison line for advice. In North America, the ASPCA Animal Poison Control Center is on 888-426-4435 and the Pet Poison Helpline, open 24/7, is on 855-764-7661. The Pet Poison Helpline charges a per-incident fee. In the UK and elsewhere, call your own vet or the nearest emergency clinic.

How to prevent antifreeze poisoning

Most cases are accidents, and most are preventable. From the RSPCA, Cats Protection, PDSA and PetMD:

  • Store it sealed and high. Keep antifreeze in its original, clearly labeled, tightly closed container, out of reach of pets.
  • Clean up every spill. Even small ones. Merck suggests covering spills with an absorbent like cat litter or sawdust, then cleaning the area.
  • Check your car for leaks. A small puddle under the engine is worth investigating.
  • Never leave drained coolant in an open tray. Dispose of old antifreeze the way your local council or waste service advises.
  • Keep pets out of garages and sheds while you work on the car.
  • Wipe paws after walks. The BVA recommends this in winter, when paws can pick up grit and chemicals.
  • De-ice without chemicals. Cats Protection suggests a windshield cover or scraping by hand.

Is "pet-safe" antifreeze really safe? Antifreeze made with propylene glycol has "a much wider margin of safety," says the ASPCA. It isn't harmless, though. Merck notes it can still cause a similar illness, and Cats Protection calls it "not completely non-toxic but much safer."

What about bittering agents? In December 2012, US manufacturers agreed to add a bittering agent, denatonium benzoate, to consumer antifreeze and coolant in all 50 states, following laws in 17 states. PDSA still recommends choosing a bittered product but says bittering is "not completely reliable." A bitter taste won't stop every pet, and it does nothing for a cat grooming a spill off its fur.

Cats are at the highest risk

Cats need less antifreeze to be poisoned, they have a shorter treatment window, and they often roam out of sight, across driveways and through garages. An outdoor cat can find a spill you'll never see.

Sadly, not every case is an accident. The RSPCA says it's "deeply concerned about intentional antifreeze poisonings of cats across Britain," and deliberately poisoning an animal can be an offense under the Animal Welfare Act 2006. In the US, in June 2026, eight dead cats and kittens suspected of being fed antifreeze were brought to the Fulton County Humane Society in Ohio.

If your cat comes home wobbly, drooling or "drunk," don't wait to see if it passes. And if your cat doesn't come home at all during a cold snap, start looking straight away. You can report a missing pet on Paw Alert, our free app, so neighbors nearby know to keep an eye out.

Frequently asked questions

How long does it take for antifreeze to affect a dog or cat?

Signs can start within 30 minutes. Kidney failure follows within 12 to 24 hours in cats and 36 to 72 hours in dogs, according to the Pet Poison Helpline. Pets can look better for a while in between, so don't wait for signs.

Can a pet survive antifreeze poisoning?

Yes, if treatment starts early enough. PetMD says dogs treated promptly usually have no long-term effects. Once kidney failure has developed, the outlook is very poor, and cats that survive may be left with long-term kidney disease, says Cats Protection.

Is windshield washer fluid toxic to pets?

Some is. PDSA, VCA and Cats Protection list screen wash and de-icers among products that can contain ethylene glycol. Check the label, store it like antifreeze and clean up any drips.

Do snow globes contain antifreeze?

Some do. The ASPCA lists snow globes among household products that can contain ethylene glycol. If one breaks, keep pets away and clean up the liquid right away.

Sources