VeterUSA · Emergency triage
Did your pet drink antifreeze?
Ethylene glycol is in radiator antifreeze/coolant and some de-icers and brake fluids. It tastes sweet, so pets readily lap it up. Enter what you know — but for antifreeze, the answer is almost always "go now."
This is one of the fastest, most lethal pet poisons — a few licks can kill a cat. The antidote only works in a narrow window (cats ~3 hours, dogs ~5–8 hours), so do not wait for symptoms. Go now.
Rough reference
- A few licks~1–3 mL
- 1 teaspoon5 mL
- 1 tablespoon15 mL
Lethal dose is tiny: ~1.4 mL/kg for cats, ~4.4 mL/kg for dogs. For a 10 lb cat that's about 6 mL — barely more than a teaspoon.
Both helplines are staffed 24/7 by veterinary toxicologists. With antifreeze, call on the way rather than before leaving — the antidote's effectiveness drops by the hour.
Why antifreeze is so deadly
The dangerous ingredient is ethylene glycol. The liver converts it into toxic acids that form crystals in the kidneys, causing irreversible acute kidney failure. It tastes sweet, so pets — especially cats — drink it readily, and the toxic dose is alarmingly small.
How little is lethal
The minimum lethal dose is roughly 1.4 mL per kg for cats and 4.4–6.6 mL/kg for dogs. For a 10 lb (4.5 kg) cat that's only about a teaspoon; for a 50 lb (23 kg) dog, around 100 mL. A small spill in the garage is enough.
The deceptive timeline
Within 30 minutes to 12 hours, pets often look "drunk" — wobbly, disoriented, drinking and urinating more. Then they may seem to improve, which fools owners into waiting. By the time kidney failure sets in (about 12–24 hours in cats, 24–72 in dogs), it's often too late. That's why you act on the exposure, not the symptoms.
The antidote is a race against time
Antidotes (fomepizole or ethanol) work by stopping the liver from creating the toxic byproducts — so they only help before those form. For cats the window can be as short as 3 hours; for dogs, roughly 5–8. Every minute matters.
Is this calculator a substitute for a vet?
No — and with antifreeze, even a small or uncertain amount is an emergency. Don't use the estimate to talk yourself out of going. Call a vet or poison control and head to the nearest open hospital immediately.