Toxic to dogs · Chemicals

Is Antifreeze toxic to dogs?

Extreme severity No safe amount — No amount is considered safe.

Yes, Antifreeze is extremely toxic to dogs. Even a small amount can be life-threatening, so treat any exposure as an emergency and contact a vet immediately. No amount is considered safe.

Video explainer

Why is antifreeze toxic to dogs and cats?

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What to do right now

  1. Go to your vet or an emergency vet now if you know or even suspect your dog drank antifreeze or coolant. Don't wait for signs: Pet Poison Helpline says dogs must be treated within 8 to 12 hours, and the longer treatment is delayed, the worse the outlook.
  2. Call ahead on the way. In the US: Pet Poison Helpline (855) 764-7661 or ASPCA Animal Poison Control (888) 426-4435. Pet Poison Helpline charges a fee.
  3. Bring the antifreeze container or label so the vet can judge the amount and the ingredients.
  4. Don't try to make your dog vomit at home. Ethylene glycol is absorbed so fast that even decontamination at the clinic may not help, and a dog that already shows neurologic signs must never be made to vomit, because it could breathe in the vomit.

Go to an emergency vet if

  • Your dog drank or licked antifreeze, coolant or another product that may contain ethylene glycol, or you think it might have. Go even if it seems fine: the antidote only works early.
  • Your dog acts drunk, walks unsteadily, vomits, or suddenly drinks and urinates a lot, especially after time in a garage, on a driveway or near a car.
  • Your dog seemed drunk earlier and now seems better. That is not a sign of recovery: apparent improvement is a known stage while internal damage continues.
  • Your dog has a seizure, collapses, becomes very lethargic, or passes little or no urine.
  • A snow globe broke and your dog licked the liquid.

Symptoms to watch for

  • incoordination
  • drooling
  • vomiting
  • seizures
  • excessive thirst
  • excessive urination
  • inappetance
  • lethargy
  • coma
  • acute kidney failure

How much is dangerous

A very small amount can kill a dog. The Merck Veterinary Manual gives the minimum lethal dose of undiluted ethylene glycol in dogs as 4.4 to 6.6 mL per kg of body weight. In household terms, Merck's pet-owner page says 3 to 4 teaspoons can be lethal for a dog, without giving a dog size, and Pet Poison Helpline says a tablespoon or two can be fatal, depending on the dog's size. Merck notes that younger animals in general may be more susceptible. Treat any amount as an emergency.

When signs appear

Time matters more than anything. Pet Poison Helpline says dogs must be treated within 8 to 12 hours of drinking antifreeze, and Merck says the outlook gets worse the longer treatment is delayed, so don't wait for signs. Ethylene glycol is absorbed quickly, peaking within 1 to 4 hours. Signs that look like drunkenness start 30 minutes to 12 hours after drinking. The ASPCA says problems can start within a couple of hours but early signs are sometimes missed, and pets may be clearly ill by 6 to 12 hours. From about 12 hours (Pet Poison Helpline gives 12 to 24 hours), the drunk signs can seem to fade and the dog may look better. That is not a sign of recovery: internal damage continues. Severe kidney failure usually develops 36 to 72 hours after drinking.

Why it's dangerous

Ethylene glycol is metabolized into toxic byproducts that cause severe acute kidney failure and central nervous system depression.

Toxic compound: Ethylene glycol

How vets treat it

The vet runs blood tests for ethylene glycol (some clinics have in-house kits), other bloodwork and urine tests for calcium oxalate crystals. In-house tests are less sensitive and specific than testing at a human hospital lab, and the vet may start treatment before the diagnosis is confirmed if no reliable test is available. The antidote is fomepizole (4-MP), the treatment of choice in dogs, or ethanol if fomepizole isn't available. Both block the enzyme that turns ethylene glycol into the breakdown products that damage the kidneys. Your dog also gets IV fluids to correct dehydration and flush ethylene glycol out in the urine, and the vet corrects acidosis, low blood sugar or low calcium as needed. Once the kidneys are failing and urine output has dropped or stopped, the antidote is of little benefit, because almost all of the ethylene glycol has already been broken down.

Outlook

The outlook depends on how fast treatment starts: the longer the delay, the worse it gets. Calcium oxalate crystals in the urine signal a poor prognosis, and in dogs they can appear as early as 6 hours after drinking. Once kidney failure has developed, the prognosis is poor.

Where pets are exposed

  • Car antifreeze and radiator coolant, the main source. The poison in them is ethylene glycol. Concentrated antifreeze can be up to about 95% ethylene glycol, and premixed 50/50 coolant is also sold.
  • Spills and leaks on garage floors and driveways, leaking cars, containers kept in garages and sheds, and old coolant that was not disposed of properly. Pets lap up the puddles.
  • Antifreeze tastes sweet, which tempts pets to drink it. US makers have added a bittering agent since 2012, but the Merck Veterinary Manual says some animals may still find it palatable.
  • Toilets and RV plumbing winterized with antifreeze. Pet Poison Helpline sees dogs that drank from toilets in cabins.
  • Some snow globes, which have been found to contain ethylene glycol. A pet that licks the liquid from a broken globe can be poisoned.
  • Other products: windshield de-icers (some contain less ethylene glycol), aircraft de-icers, brake, transmission and hydraulic fluids, motor oil, and less obvious ones such as solar heating fluids, ice-rink freezing equipment, bases of portable basketball hoops, paints, solvents, wood stains, printer and pen inks, photo-developing fluids and some eye masks.
  • In cats, poisoning has been reported from ethylene glycol absorbed through the skin from topical products.
  • Cases peak when people add antifreeze or flush radiators. Merck says that is fall, winter and early spring in cold climates; Pet Poison Helpline names summer and winter.

Prevention

  • Store antifreeze in closed containers out of pets' reach, and dispose of old antifreeze properly.
  • Clean up any spill or leak at once. Soak it up with cat litter, sand or sawdust, or dilute it with several gallons of water, so pets can't lick the residue.
  • Choose propylene glycol-based antifreeze, sold as 'pet-safe', where you can. It has a much wider margin of safety, but it is not harmless, so keep pets away from it too.
  • Keep pets away from leaking cars, from garages and sheds where coolant is kept, and from toilets or RV plumbing winterized with antifreeze.
  • Keep snow globes where pets can't knock them over, and keep pets away from a broken one.
  • Keep other car fluids out of reach as well, including brake and transmission fluids and windshield de-icers.

Good to know

Poisoning occurs in three stages; stage 2 may appear as a temporary recovery while internal damage progresses. Propylene glycol is a safer alternative found in some products.

Common questions

How much antifreeze can kill a dog or a cat?

Very little. Merck's pet-owner page puts the lethal amount at 1 to 2 teaspoons for a cat and 3 to 4 teaspoons for a dog. Pet Poison Helpline says one teaspoon can be fatal to a cat, and a tablespoon or two to a dog, depending on its size. Cats are far more sensitive: the Merck Veterinary Manual gives a minimum lethal dose of undiluted ethylene glycol of 1.4 mL per kg in cats, against 4.4 to 6.6 mL per kg in dogs.

How long do I have to get my pet treated after it drinks antifreeze?

For cats, only a few hours: Pet Poison Helpline says treatment must start within 3 hours, and ASPCApro says within 4 hours. For dogs, Pet Poison Helpline says within 8 to 12 hours. In both species, the outlook gets worse the longer treatment is delayed, so go to a vet immediately rather than waiting for signs.

My pet drank antifreeze but seems fine. Is it okay?

Not necessarily, so go to a vet now. Early signs can be missed, and pets can seem to recover around 12 hours after drinking while the kidneys are being damaged. The antidote helps only before kidney failure sets in.

Should I make my pet throw up after it drinks antifreeze?

No, don't do it at home. Go to your vet or call a poison line instead. Merck says ethylene glycol is absorbed so fast that even decontamination at the clinic may not help, and a pet with neurologic signs must never be made to vomit. Fast veterinary treatment with the antidote is what improves the outlook.

Is 'pet-safe' propylene glycol antifreeze actually safe?

It is much safer than ethylene glycol, but it is not safe to drink. Merck says it causes a similar but milder poisoning, and Pet Poison Helpline says concentrated propylene glycol antifreeze can quickly cause sedation, stumbling and seizures. In cats, repeated exposure can cause severe anemia. Still keep it away from pets.

Can a broken snow globe poison my dog or cat?

It can. Pet Poison Helpline, the ASPCA and ASPCApro all say some snow globes have been found to contain ethylene glycol. If a globe breaks and your pet licks the liquid, treat it like antifreeze and go to a vet right away. No source says how much a typical globe contains.

Sources

This page is informational and is not veterinary advice. If your pet has been exposed to something risky, contact your vet or an animal poison control line right away.

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