Safety & toxicologyDogCat

Antifreeze (ethylene glycol): fatally toxic to animals

Antifreeze (ethylene glycol) is fatally toxic to dogs and cats. Even small amounts cause acute kidney failure. EMERGENCY: go to the vet immediately.

Strong evidenceSeveral good studies in the target species (systematic review/meta-analysis or consistent RCTs) point the same way. We are reasonably certain about the effect.

Published: 27 June 2026Last updated: 27 June 2026Next review: 27 June 20272 min read

Short & honest

Strong evidence (grade A): ethylene glycol is one of the most life-threatening household toxins for dogs and cats. Without immediate treatment, the chance of survival is very small, especially in cats.

Safety assessment: Toxic — do not use

Veterinary review not yet completed

This page is awaiting review by a registered veterinary surgeon. Until then, treat the text as education based on the sources listed — not as a verified veterinary judgement.

🚨 In doubt, or an emergency? Do not wait — call your vet.

Call a vet immediately if you see:

Vomiting and nausea within 30–60 minutes after possible exposure
Drunken or unsteady gait, disorientation (resembles alcohol intoxication)
Excessive drinking and/or urination shortly after exposure
Seizures or loss of consciousness
Cessation of urine production (anuria/oliguria) — sign of kidney failure
Collapse or coma — in cats as early as 12–24 hours, in dogs after 36–72 hours

Acute or life-threatening (breathing difficulty, unresponsive, seizures, bloated abdomen): call your vet or the out-of-hours veterinary service immediately.
(Possible) poisoning or ingestion of a toxic substance: call your vet straight away — do not wait for symptoms. Bring the packaging.
No substitute: never use a natural product instead of a proven, necessary treatment.

What is ethylene glycol?

Ethylene glycol is the active substance in most car antifreeze and coolant products. The liquid has a sweet taste, which attracts pets — and especially cats — to drink it [3]. Even a small puddle on the driveway or a broken radiator can have fatal consequences.

Why is it so dangerous?

The danger lies not in ethylene glycol itself, but in what the liver makes from it. During breakdown, among other things, oxalic acid is formed, which binds to calcium and forms calcium oxalate crystals. These crystals deposit in the renal tubules and cause irreversible acute kidney failure [2][3].

Particularly treacherous is the two-phase course:

Phase	Time (cat)	Time (dog)	Symptoms
Phase 1	0–12 hours	0–12 hours	Drunken behaviour, nausea, excessive drinking/urination
Apparent recovery	~6–12 hours	~12–24 hours	Animal appears to improve — misleading
Phase 2	12–24 hours	36–72 hours	Acute kidney failure, anuria, collapse, coma

This apparent recovery regularly leads to owners raising the alarm too late — with fatal consequences [2][3].

How quickly must treatment take place?

Every minute counts. The antidote fomepizole (4-methylpyrazole) blocks the harmful breakdown in the liver, but the time window is extremely short [1]:

Dogs: effective up to approximately 8 hours after ingestion
Cats: exclusively effective within 3 hours after ingestion — thereafter virtually no chance of survival without haemodialysis [1]

Without treatment, it is estimated that only 3% of cats and 30–40% of dogs survive poisoning [2][3].

'Safe' alternatives

Propylene glycol antifreeze is sometimes sold as 'pet-friendly' and is indeed considerably less toxic to dogs. For cats, however, propylene glycol is still dangerous and unsuitable [3]. There is no antifreeze that is safe if an animal drinks it.

Prevention

Store antifreeze in sealed, inaccessible storage
Clean up spills immediately and thoroughly
Regularly check for leaks in the vehicle cooling system
Keep animals away from garages and driveways where vehicles are parked

What to do if poisoning is suspected?

Go immediately to a veterinary practice or emergency clinic. Call ahead so they can prepare. Take the packaging with you if possible. Do not wait for further symptoms — the apparent recovery after phase 1 gives a false sense of security [3].

Inducing vomiting at home or waiting is not an option: the time window for effective treatment is too short and damage may already have begun before the animal appears ill [1][2].

Why this verdict?

Evidence is based on clinical case series (JAVMA 1984) and a narrative review of high-dose fomepizole in cats (JVECC 2010), supplemented by the Merck Veterinary Manual as a standard reference [1][2][3]. Limitations are the relatively small number of animals per study and the observational nature, but the toxicological mechanisms and clinical outcomes are well documented and consistent — this justifies grade A.

How we grade evidence →

Legal status (Netherlands)

Ethylene glycol antifreeze is freely available. There is no specific Dutch legislation regulating its use by pet owners, but intentionally administering it to an animal is punishable under the Wet dieren (Animals Act).

Sources

[1] Safety and efficacy of high-dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats. Journal of Veterinary Emergency and Critical Care, 2010. Narrative review doi:10.1111/j.1476-4431.2009.00492.x
[2] Clinicopathologic findings in dogs and cats with ethylene glycol intoxication. Journal of the American Veterinary Medical Association (JAVMA), 1984. Case series source ↗
[3] Ethylene Glycol Toxicosis in Animals. Merck Veterinary Manual. Monograph source ↗