Emergency — phone the vet now Antidote must be given within 3 hours (cats) or 8–12 hours (dogs) for best outcome

Dog or cat antifreeze poisoning (ethylene glycol)

Antifreeze is rapidly fatal — phone the vet and Animal PoisonLine (01202 509000) immediately even if the pet seems fine; the antidote works only in a narrow window.

Dog Cat

Recognise the signs

Stage 1 (30 minutes – 12 hours): wobbliness, appearing 'drunk', vomiting, increased thirst and urination
Stage 2 (12–24 hours): apparent improvement — deceptive
Stage 3 (24–72 hours): severe kidney failure — vomiting, lethargy, ulcers in mouth, no urine produced
Cats often skip the wobbly stage and present already in kidney failure

First aid steps

If you saw the pet drink antifreeze, treat as an emergency immediately — do not wait for symptoms.
Phone the emergency vet and Animal PoisonLine on 01202 509000.
Take the antifreeze container with you for the active ingredient.
Drive to the vet without delay — every hour increases kidney damage.

Do NOT

Do not wait to see if symptoms develop — apparent improvement at 12–24 hours masks fatal kidney damage.
Do not induce vomiting at home unless told to by a vet.
Do not give milk, food, or any 'detox' product.
Do not assume it must have been a tiny amount — even a teaspoon can kill a cat.

While transporting to the vet

Bring the container or a clear photo of the label.
Note the approximate amount and time of ingestion.
Keep the pet warm and quiet.

When to phone the vet immediately

Any known or suspected antifreeze ingestion, with or without symptoms
Wobbliness, vomiting, or excessive drinking after access
Reduced or absent urine output
Apparent recovery after early symptoms — still emergency

Common causes

Spilled or pooled antifreeze on driveways and garage floors
Topping up car coolant or screenwash with the lid left off
Coolant leaks under cars and in garages
Garden water features using antifreeze
Some screenwashes (read labels — methanol-based versions less acutely toxic but still harmful)

What the vet will need to know

Brand and active ingredient (ethylene glycol versus propylene glycol matters)
Approximate amount ingested
Time of ingestion
Pet's weight
Any vomiting or symptoms so far

Aftercare

Treatment uses fomepizole (dogs) or, where unavailable, ethanol IV — both work only early.
Hospitalisation 48–72 hours with intensive IV fluids and bloods.
Repeat kidney bloods over 1–2 weeks.
Some pets recover fully; others develop chronic kidney disease and need lifelong support.

Prevention

Switch to propylene glycol-based antifreeze (often sold as 'pet-safe') where possible — still not harmless but far less toxic.
Clean up any spills immediately with absorbent material then water.
Store antifreeze in sealed, clearly labelled containers up high.
Check under cars in winter for coolant drips on driveways.
Avoid garden water features with antifreeze additives.

Breed-specific notes

Cats are far more sensitive than dogs by body weight — a teaspoon can be fatal.
Small dogs need much less than large dogs to reach a fatal dose.

Frequently asked questions

Why does antifreeze attract pets?

Ethylene glycol has a sweet taste, particularly attractive to dogs but cats will also lap it from puddles. Spills on cold driveways are licked up readily.

How little antifreeze is dangerous?

Roughly 1.5 ml/kg in cats and 4–6 ml/kg in dogs is potentially fatal — meaning a teaspoon can kill an average cat and a small dog can be killed by a few tablespoons. Treat any ingestion as urgent.

Is 'pet-safe' antifreeze actually safe?

Propylene glycol-based products are far less toxic than ethylene glycol but not entirely harmless — large amounts still cause illness. Always treat any antifreeze ingestion as a vet emergency until you know the active ingredient and amount.