If your dog may have licked or drunk antifreeze, call your vet, the nearest emergency clinic or a pet poison line now, even if your dog seems completely fine. A small amount can kill a dog when treatment is delayed, and the antidote only works before the kidneys start to fail. If you wait for symptoms, you use up the hours when treatment works best.
US pet poison lines (24/7, fees may apply): ASPCA Animal Poison Control (888) 426-4435 or Pet Poison Helpline (855) 764-7661.
Suspected Antifreeze? Do This Now
- Call while you get ready to leave. Your vet, an emergency hospital or one of the poison lines above can tell you where to go and get the team ready for you.
- Don't make your dog vomit unless the vet or poison line tells you to. AAHA warns that doing it on your own can cause more harm than good, and Merck notes vomiting should never be induced in a dog that is already wobbly or dull, because it can end up in the lungs.
- Bring the container, or a clear photo of the label. Not every antifreeze contains ethylene glycol, so the product name helps the vet decide what they are dealing with.
- Say when it happened, as best you can. How the vet tests and treats depends on how many hours have passed.
- Go, even if your dog looks normal. Early signs can be mild or easy to miss, and the damage starts before you see it.
Why Antifreeze Is So Dangerous for Dogs
Many antifreeze products are based on ethylene glycol, a sweet-tasting liquid, and concentrations of up to 95% are common in concentrated radiator antifreeze. That sweet taste, plus how common antifreeze is and how often it gets stored or thrown out carelessly, is why the Merck Veterinary Manual calls the poisoning often fatal and says dogs and cats are the animals affected most. Since 2012, US makers have added a bitter agent to antifreeze and engine coolant, but Merck notes some animals will still drink it.
The ethylene glycol itself is not the main problem. The gut absorbs it within a few hours, and the liver and kidneys then break it down, step by step, into acids. Two of those breakdown products, glycolic acid and oxalate, are the real poisons: they make the blood dangerously acidic and they damage the kidney tubules. Oxalate also binds calcium and forms calcium oxalate crystals inside the kidneys. That is why antifreeze poisoning ends in kidney failure.
Cats are even more sensitive than dogs, and their kidneys fail sooner, so the same urgency applies to every pet in the house.
Symptoms of Antifreeze Poisoning in Dogs, Stage by Stage
Signs depend on how much your dog swallowed and how long ago. Merck and Pet Poison Helpline describe three phases in dogs. Your dog can be in danger at any of them, so "Call now" applies to all three.
Stage | When (after swallowing) | What you might see |
|---|---|---|
1. Looks drunk | 30 minutes to 12 hours | Wobbly walking, vomiting, drooling, drinking and peeing a lot, dull or dazed |
2. Seems better | Around 12 hours | Signs ease off, while kidney damage continues inside |
3. Kidney failure | 36 to 72 hours | Little or no urine, vomiting, diarrhea, mouth ulcers, fast breathing, painful kidneys, seizures, coma |
Stage 1 (30 minutes to 12 hours): Looks drunk
Merck says the first signs start almost immediately and look a lot like alcohol poisoning. Your dog may:
- Stumble, sway or knuckle over on the paws, as if drunk
- Vomit (the stomach lining is irritated)
- Drool heavily (AAHA lists excessive drooling as an early sign)
- Drink far more than usual and pee large amounts
- Seem dull, dazed or "not there"
Pet Poison Helpline adds that seizures can happen in this first stage too. As your dog gets duller, they drink less and start to dehydrate.
Stage 2 (around 12 hours): Seems better, but isn't
This is the stage that fools people. Merck notes that dogs may appear to briefly recover about 12 hours after drinking antifreeze. The wobbliness fades and your dog looks more like themselves. Pet Poison Helpline is blunt about what is really going on: significant internal damage is ongoing. While your dog looks brighter, the body is still turning ethylene glycol into the acids and crystals that attack the kidneys. A dog who "seems fine now" after a possible exposure still needs a vet, today.
Stage 3 (36 to 72 hours): Kidney failure
In dogs, Merck puts severe kidney failure at 36 to 72 hours after ingestion. Signs include:
- Making little urine, then none at all
- Lack of energy and no appetite
- Vomiting and diarrhea
- Mouth ulcers and drooling
- Fast breathing and a fast heart rate
- Swollen, painful kidneys
- Dehydration
- Seizures, coma and death
For a wider look at how failing kidneys show up in dogs, see our guide to the signs of kidney failure in dogs.
Why Time Matters So Much
Merck states that the outlook gets worse the more time passes between swallowing antifreeze and starting treatment. The antidote works by stopping the body from making the toxic breakdown products, so it can only help while there is still ethylene glycol left to block. Merck's owner guide says it is only effective if given before kidney failure develops.
How long is that window? AAHA says antidotes work best within about eight hours, and Pet Poison Helpline says dogs should receive treatment within 8 to 12 hours. Treat those numbers as a reason to leave now, not as time you can spend watching your dog. Once the kidneys have shut down, Merck describes the outlook as guarded to poor.
What Your Vet Will Do
How the Vet Confirms It
If nobody saw your dog drink antifreeze, the vet pieces it together from your story, an exam and lab work. Merck lists a quick in-clinic ethylene glycol blood test, bloodwork, a blood gas and a urinalysis. Under the microscope, the vet or technician may find calcium oxalate crystals in the urine. Merck notes these can show up as early as about 6 hours after ingestion in dogs, and that finding them is a poor sign.
How the Vet Treats It
Your vet chooses the treatment and the doses based on your dog, the product and the timing. According to Merck and AAHA, it usually includes:
- Sometimes, emptying the stomach. If the exposure was very recent and your dog is alert, the vet may decide to make your dog vomit. Ethylene glycol is absorbed fast, so this helps only early, and it is not done in a dog with neurologic signs.
- IV fluids to correct dehydration, help flush ethylene glycol out through the urine and support the kidneys.
- An antidote. Fomepizole (also called 4-MP) blocks the enzyme that turns ethylene glycol into its toxic products, and Merck calls it the treatment of choice in dogs. When it isn't available, vets can use medical ethanol given through an IV line in the hospital. This is a monitored hospital treatment; never give your dog alcohol at home.
- Supportive care, such as correcting the blood's acid balance, blood sugar and calcium, and close monitoring of how much urine your dog makes.
Dogs that are treated early have the best chance. Dogs already in kidney failure may receive intensive fluid therapy, but the outlook is poor.
Where Antifreeze Hides
Radiator coolant in the garage is the obvious source. Merck and Pet Poison Helpline list some less obvious ones:
- Puddles under a leaking car or truck, on the garage floor or the driveway
- Open or chewed containers in garages and sheds
- Old coolant drained during a flush and left in a pan or poured on the ground
- Heat-exchange fluid in some solar collectors
- Ice-rink freezing equipment
- Some brake and transmission fluids
- Winterized RV plumbing, including RV toilets
Most cases happen in fall, winter and early spring, when people top up or flush their cooling systems.
How to Prevent Antifreeze Poisoning
- Store it sealed and out of reach. Keep antifreeze in a tightly closed container in a locked cabinet or on a high shelf, as AAHA recommends.
- Clean up spills right away. AAHA notes that a few drops on the garage floor or driveway can attract a curious pet. Merck suggests covering the spot with cat litter, sawdust or another absorbent material after you clean it, so there is nothing left to lick.
- Check where you park. Look for drips and puddles under your vehicles regularly, and get leaks fixed.
- Get rid of old coolant safely. Merck lists careless disposal among the reasons this poisoning is so common. Never pour used antifreeze on the ground or leave a full drain pan where a dog can reach it.
- Consider propylene glycol antifreeze. Products based on propylene glycol are less toxic than ethylene glycol and less sweet, so pets are less drawn to them. They still carry risk: Merck notes propylene glycol can still cause a similar, milder poisoning, and AAHA says they aren't risk-free.
- Watch for antifreeze in toilets. Keep dogs away from RV toilets and any other plumbing winterized with antifreeze, and keep the lid down and the bathroom door closed.
Antifreeze Poisoning FAQ
How long does it take for antifreeze to affect a dog?
Signs can start within 30 minutes and usually appear within 12 hours: wobbliness, vomiting, drooling, thirst and lots of urine. Kidney failure follows at 36 to 72 hours. Don't wait for any of it: call as soon as you suspect exposure.
Can a dog survive antifreeze poisoning?
Yes, when treatment starts early, before the kidneys fail. Merck says the outlook depends on how much time passes before treatment, and it is poor once kidney failure has set in.
Is "pet-safe" antifreeze really safe?
Propylene glycol antifreeze is less toxic than ethylene glycol, and Merck notes the outlook is usually better, but it is not harmless. If your dog drinks any kind of antifreeze, call your vet or a poison line and have the label ready.
Originally written by Dr. Catharina Hjorth. Updated by the I Love Veterinary editorial team.
Sources
- Merck Veterinary Manual: Ethylene Glycol Toxicosis in Animals
- Merck Veterinary Manual: Ethylene Glycol (Antifreeze) Poisoning
- AAHA: Paws Off! Protecting Your Pet from Antifreeze Toxicity
- Pet Poison Helpline: Antifreeze
- Pet Poison Helpline: Antifreeze Poisoning in Pets
- ASPCA Animal Poison Control Center
This article is for general information and is not a substitute for advice from your veterinarian.
