Antifreeze is one of the most dangerous poisons for dogs: it usually contains ethylene glycol, a sweet-tasting substance that can cause fatal kidney failure even when swallowed in small amounts. If you think your dog has licked or drunk antifreeze, call your vet straight away, without waiting for symptoms: treatment works better the earlier it starts. Here is what you need to know about antifreeze poisoning in dogs, its symptoms and the right habits on walks.
Why is antifreeze so dangerous for dogs?
The Merck (MSD) Veterinary Manual explains that most ethylene glycol poisonings come from car radiator antifreeze, which can contain up to 95% ethylene glycol. Two features make it particularly treacherous.
- Its sweet taste. It attracts animals rather than putting them off. A dog may lap at a puddle out of curiosity and then come back for more.
- Its toxicity in small doses. The pet owner version of the manual states that around 3 to 4 teaspoons can be enough to kill a dog. The professional version gives the minimum lethal dose by body weight (4.4 to 6.6 mL of undiluted ethylene glycol per kilogram): the smaller the dog, the smaller the dangerous amount.
Ethylene glycol itself is not the main problem: it is the way the body breaks it down that produces toxic compounds, which damage the kidneys. That is why the first few hours matter so much.
Where can a dog come across antifreeze?
The garage comes to mind first, but the risk also exists on walks. According to the veterinary sources consulted, ethylene glycol can be found in:
- car radiator antifreeze, the leading cause of poisoning;
- some screen wash, according to the PDSA, the UK veterinary charity;
- some brake and transmission fluids;
- some heat-exchange fluids, such as those used in solar panels;
- some garden water features, again according to the PDSA.
On walks, the situations to watch are leaks under parked cars, puddles in car parks and on driveways, and old abandoned containers: the PDSA reports that dogs have been poisoned by drinking rainwater that had collected in used antifreeze containers. A dog can also walk through a puddle and lick its paws once home. If your dog tends to taste everything outdoors, our article on dogs that eat everything on walks gives practical exercises to discourage it.
Antifreeze poisoning in dogs: the symptoms
The signs develop in several stages. The Merck Veterinary Manual describes the following course in dogs.
| Time after ingestion | What you may see |
|---|---|
| 30 minutes to 12 hours | Signs resembling drunkenness: vomiting, excessive thirst and urination, depression, wobbly gait, lack of coordination. |
| Around 12 hours | Temporary improvement: the dog may seem to recover. |
| 36 to 72 hours | Acute kidney failure: severe lethargy, loss of appetite, vomiting, diarrhoea, mouth ulcers, drooling, rapid breathing, dehydration, sometimes seizures, coma and death. |
The PDSA adds that the first symptoms can appear within an hour of swallowing it, and that the dog drinks and urinates more at first, then much less one to three days later, once the kidneys are affected.
The trap is the apparent recovery: a dog that was “staggering” and seems fine the next morning is not out of danger. And the absence of symptoms proves nothing either, especially in the first few hours.
What to do if your dog has drunk antifreeze
This is a veterinary emergency. The sources agree: the outlook worsens as more time passes between ingestion and the start of treatment.
- Call your vet immediately or, at night and at weekends, the out-of-hours vet, even if your dog seems well. The PDSA states that treatment works best when started early, ideally within 12 hours.
- Do not make your dog sick yourself. According to the PDSA, inducing vomiting only helps in the very early stages; once the antifreeze has been absorbed, it brings no benefit. That decision is for your vet. The Merck manual specifies that decontamination measures are most effective within one to two hours of ingestion.
- Stop your dog licking itself if it has walked through the product or has some on its coat, and tell your vet: the PDSA lists washing the paws and coat among possible treatments.
- Note what you know: the product involved (keep the packaging if you have it), the likely time of ingestion and the estimated amount.
In France, the Centre national d’informations toxicologiques vétérinaires (CNITV), near Lyon, takes calls from owners and vets alike on +33 4 78 87 10 40, seven days a week, from 8.30am to midnight. In the UK, contact your vet or the out-of-hours service. A phone line helps you assess the situation but never replaces an examination: only a vet can examine and treat your dog.
The Merck manual states that an antidote exists for dogs but is only effective before kidney failure develops. The choice of treatment rests entirely with your vet. Never try a “home remedy”.
Preventing antifreeze poisoning, at home and on walks
At home and in the garage
- Store antifreeze, screen wash and brake fluid in their original sealed, labelled containers, out of reach.
- Clean up any leak immediately, then cover the area with cat litter, sawdust or another absorbent material, as the Merck manual advises, so that animals cannot lick the residue.
- Take old containers to a recycling centre rather than leaving them outside, where they fill with rainwater.
- If you are choosing an antifreeze, the Merck manual notes that propylene glycol is less toxic than ethylene glycol and lacks its sweet taste. The PDSA also mentions products with an added bittering agent, while pointing out that this protection is not fully reliable.
On walks
- Keep your dog on a short lead alongside parked cars, in car parks and on driveways, and steer it away from coloured or suspicious puddles. The PDSA advises walking dogs away from areas where spills may have occurred.
- Use a fixed lead rather than a retractable one in these places: you stay in control of the distance. Our article retractable leads: good idea or danger? explains why.
- A well-fitted harness with a handle helps you guide your dog and move it quickly away from a puddle; you will find some in our harness collection.
- After a walk, keep an eye on your dog if it licks its paws insistently after possibly stepping in a dubious puddle, and call your vet if in any doubt.
Winter brings several risks together: cold, salted pavements, longer nights. To adapt your walks, also read at what temperature does a dog feel the cold?
Frequently asked questions
Can a dog survive antifreeze poisoning?
Yes, if treated quickly. The Merck manual points out that the outlook depends above all on the time between ingestion and treatment: the shorter it is, the better the chances. Once kidney failure has set in, the situation becomes much more serious.
My dog only licked a puddle: is it serious?
You cannot tell by looking: the dangerous amount is small, especially for a small dog, and symptoms can be delayed. Call your vet straight away: they will assess the risk.
Is screen wash just as dangerous?
Some screen washes contain ethylene glycol, according to the PDSA, but formulations vary. Treat any car fluid as potentially toxic and contact your vet if your dog swallows some.
Sources
- Grauer G. F. (2020, updated 2024). Ethylene Glycol (Antifreeze) Poisoning. Merck Veterinary Manual (pet owner version).
- Regehr T. (2022, updated 2024). Ethylene Glycol Toxicosis in Animals. Merck Veterinary Manual (professional version).
- PDSA. Antifreeze poisoning in dogs. PDSA Pet Health Hub.
- CNITV. Centre anti-poison vétérinaire. Centre National d’Informations Toxicologiques Vétérinaires (France).