Did your dog or cat drink antifreeze? Check the dose and act now.
Estimate how much ethylene glycol your dog or cat swallowed from antifreeze, engine coolant, or another ethylene glycol product, and compare it with the published minimum lethal dose for their species. Every result on this page is an emergency, because the antidote only works if it is started within hours.
Antifreeze is a race against the clock. Do not wait for symptoms.
The antidote (fomepizole or ethanol) must be started within about 3 hours for cats and about 8 to 12 hours for dogs to be effective (Pet Poison Helpline). As little as one teaspoon can be fatal to a cat, and a tablespoon or two to a dog. Pets can look better around 12 hours after drinking while their kidneys are failing. If you think your pet drank any antifreeze, go to an emergency vet now and use this page on the way.
Assess the situation
Fill in what you know. Estimates are fine. If you are not sure how much, check the box and the result will still tell you what to do.
Assessing
-Estimated dose (mL ethylene glycol per kg body weight)
-Estimated ethylene glycol swallowed (mL)
This is an estimate, not a diagnosis, and it can be wrong. Whatever the result, get your pet to a veterinarian now and call a poison control line on the way: ASPCA Animal Poison Control (888) 426-4435 or Pet Poison Helpline (855) 764-7661 (fees may apply). Read the medical disclaimer.
Emergency vet or poison control: which do I call?
For antifreeze, the answer is usually both: start driving to an emergency vet and call poison control on the way so the hospital has a treatment plan when you arrive. Vets confirm exposure with a blood test for ethylene glycol and blood gases, then give the antidote, fomepizole (4-MP) or ethanol, plus IV fluids. The Merck Veterinary Manual notes that the outlook gets worse the longer treatment is delayed.
Go straight to an emergency vet if…
Your pet drank, licked, or walked through any antifreeze or coolant
Your pet is a cat (the treatment window is about 3 hours)
Your pet seems drunk, wobbly, is vomiting, drinking or peeing a lot, or is very sleepy
You found a leak, spill, or chewed bottle and cannot rule out drinking
Call poison control on the way if…
You are not sure whether the product contains ethylene glycol or propylene glycol
Your regular vet is closed and you need to know where to go
You want a case number and treatment plan to hand to the emergency vet
The product is something other than car antifreeze
Do not make your pet vomit at home unless a veterinarian or poison control tells you to, and never if your pet is wobbly or having trouble swallowing. Ethylene glycol is absorbed fast, so the antidote matters far more than home first aid. If antifreeze is on the fur or paws, wipe it off and keep your pet from licking it, then head in.
How antifreeze poisoning develops
Ethylene glycol itself acts a bit like alcohol. The real damage comes as the liver turns it into acids and oxalate, which form calcium oxalate crystals in the kidneys. The antidote works by blocking that conversion, which is why it only helps early (Merck Veterinary Manual).
30 minutes to 12 hours
Looks like drunkenness
Wobbly walking, stumbling, knuckling
Vomiting, drooling
Drinking and peeing a lot, sleepiness
About 12 to 24 hours
False recovery
Pets may seem to improve
Fast heart rate and fast breathing
Dehydration while kidney damage continues
Cats 12 to 24 h, dogs 36 to 72 h
Kidney failure
Little or no urine, painful kidneys
Not eating, vomiting, mouth ulcers, drooling
Severe lethargy, seizures, coma, death
Stages and timing are from the Merck Veterinary Manual and Pet Poison Helpline. Once kidney failure has set in, the antidote is of little benefit and the outlook is guarded to poor, so treatment must start before signs get worse.
Published data behind these estimates
These figures come from the Merck Veterinary Manual and Pet Poison Helpline. They describe documented effects, not a line between "safe" and "dangerous." Kidney injury can happen below the minimum lethal dose.
Dose, product, or timing
Documented effect or content
1.4 mL/kg (cats)
Minimum lethal dose of undiluted ethylene glycol in cats (Merck Veterinary Manual)
4.4 to 6.6 mL/kg (dogs)
Minimum lethal dose of undiluted ethylene glycol in dogs (Merck Veterinary Manual). This calculator uses the low end, 4.4 mL/kg.
1 teaspoon / 1 to 2 tablespoons
Amount of antifreeze that can be fatal to a cat / to a dog, depending on size (Pet Poison Helpline)
Concentrate
Up to 95% ethylene glycol (Merck Veterinary Manual); 95 to 100% (Pet Poison Helpline)
Premixed coolant
Sold as 50/50 prediluted ethylene glycol; concentrate is also diluted about 50% in car cooling systems (Merck Veterinary Manual)
Antidote window
Within about 3 hours for cats and about 8 to 12 hours for dogs (Pet Poison Helpline)
This calculator shows every result as Emergency, for dogs and cats, at any amount, including when the amount is unknown. Doses at or above the minimum lethal dose (4.4 mL/kg for dogs, 1.4 mL/kg for cats) add a lethal-range warning. There is no published dose below which antifreeze is known to be harmless, so there is no "safe" or lower-urgency result.
Common questions
How much antifreeze is toxic to a dog?
The Merck Veterinary Manual gives the minimum lethal dose of undiluted ethylene glycol as 4.4 to 6.6 mL per kg in dogs. Pet Poison Helpline says a tablespoon or two can be fatal to a dog, depending on size. Kidney damage can happen below a lethal dose, so treat any amount as an emergency.
How much antifreeze is toxic to a cat?
Cats are far more sensitive. The minimum lethal dose of undiluted ethylene glycol is 1.4 mL per kg in cats (Merck Veterinary Manual), and Pet Poison Helpline says as little as one teaspoon can be fatal. Any antifreeze exposure in a cat is an emergency.
How long do I have to get my pet treated after antifreeze?
Very little time. Pet Poison Helpline says the antidote must be started within about 3 hours for cats and within about 8 to 12 hours for dogs to be effective. Once kidney failure develops, the outlook is poor. Go to an emergency vet now, even if your pet seems fine.
My pet seems fine after drinking antifreeze. Can I wait?
No. Early signs look like drunkenness and can fade around 12 hours after drinking, while kidney damage keeps getting worse. By the time a pet looks very sick, it may be too late for the antidote. Go now.
Is pet-safe antifreeze safe?
Products made with propylene glycol have a much wider margin of safety than ethylene glycol (ASPCA), but they are not harmless: large amounts can cause severe sedation, wobbliness, and seizures, and cats are especially sensitive (Pet Poison Helpline) and labels can be hard to read in a hurry. Bring the bottle and call poison control for any antifreeze your pet drinks.