A cat that laps 2 mL of ethylene glycol antifreeze — under half a teaspoon — is in a 30-minute race, and the only useful move at home is the car. Call the clinic while you load the carrier, and say 3 things: antifreeze, about 2 mL, 10 minutes ago. On the way, do not induce vomiting, do not give milk, oil or alcohol, do not force water, and do not wait at home to see whether symptoms appear.
What 2 mL does in the first 30 minutes
Ethylene glycol leaves the stomach within 30 minutes and peaks in the blood at 1-2 hours. The commonly cited minimum lethal dose is about 1.5 mL per kg, so a 3 kg cat sits near 4-5 mL — but lapping volume is under-estimated by 2-3 times, and 2 mL on a 2 kg kitten is already 1 mL per kg. Until a vet says otherwise, treat 2 mL as a lethal dose.
Cats cannot taste sweetness, so the sweet flavor does not lure them in; the puddle on the garage floor does, and so does the smell of a spill. One bottle cap holds 5 mL. One teaspoon holds 5 mL. A puddle the size of a coin holds 1-2 mL, which is the whole problem.
The 30-minute window, and what it is for
Decontamination — lavage, an absorbent, activated charcoal — only pays inside the first 30-60 minutes. After that the alcohol is in the bloodstream and the argument moves to the antidote. An in-house ethylene glycol test needs about 1 mL of serum and returns a value in 20-30 minutes; a clinic without the kit sends blood out and burns 12-24 hours you do not have.
So the phone call has 2 jobs: confirm the clinic has both the test and the antidote on the shelf tonight, and start the engine. A 45-minute drive to a hospital that has both beats a 10-minute drive to a clinic that has neither.
The 3 symptom groups, by clock
Group 1, nervous signs, 30 minutes to 2 hours. Wobbling, head held low, walking into walls, crying, tremor, then a seizure. This is the stage where the cat looks drunk and owners decide to wait. A fit here is not a side effect to ride out: 2 in 24 hours means admission.
Group 2, gut signs, 1 to 6 hours. Drooling, 2-4 vomits, a belly that hurts when lifted, sudden thirst and large volumes of urine. Easy to blame on a hairball.
Group 3, kidney signs, 12 to 72 hours. Urine output under 1 mL per kg per hour, then none at all, dehydration, mouth ulcers, breath that smells of urine, seizures, coma. Calcium oxalate crystals plug the tubules, and this stage is often permanent.
The 0-1-2-6-24 hour timeline
| Hour | What the cat looks like | What to do | Number that matters |
|---|---|---|---|
| 0-0.5 | Completely normal, maybe just a wet chin | Car, phone, carrier | 2 mL can be lethal; 30 min absorption window |
| 1 | Wobbly walk, drinking and urinating more | Arrive, draw blood | In-house test reads in 20-30 min |
| 2 | Vomiting, dull, breathing faster | Admit, start antidote | Best results if started within 3 h |
| 6 | May look better than at hour 2 | Stay in hospital | False recovery; crystals already forming |
| 24 | Little or no urine, dehydration, bad breath | Intensive care, discuss dialysis | Under 1 mL/kg/h of urine is the alarm |
What never to do on the way
- Do not induce vomiting. Part of the dose is already absorbed by minute 30, so you are vomiting up the harmless fraction while risking aspiration — a second emergency inside 24 hours.
- Do not give milk, oil or alcohol. Milk does not bind ethylene glycol, oil speeds absorption, and alcohol is an antidote ingredient whose dose belongs to a vet with a prescription pad.
- Do not syringe water into the mouth. A mouthful in the airway means aspiration pneumonia on top of poisoning.
- Do not wait 12 hours to see whether symptoms show. By the time they show, the tubules are already dying.
- Do not stop to wash the floor first. Take 1 photo of the spill, bag the bottle, and drive.
Antidote: name only, prescription only
Fomepizole blocks the enzyme that converts ethylene glycol into oxalic acid, and it works best inside 3 hours. Ethanol does the same job by competing for the same enzyme. Both are prescription drugs: the dose depends on body weight, blood pH, kidney values and whatever else the cat is taking, so no number belongs in a home article — ask the clinic for a prescription-based plan. Call ahead and ask whether fomepizole is stocked; if it is not, ask for the nearest hospital that has it, then drive there instead.
Dialysis is the escalation for a late arrival or rising kidney values. It is not available everywhere, and it runs $1,500-4,000.
Rough prognosis by clock: treated inside 3 hours, most cats leave with working kidneys; at 12-24 hours survival drops sharply and many need 3-5 days of fluids; past 72 hours with no urine, the conversation turns to euthanasia.
Where it hides at home
Car antifreeze, windshield washer fluid, solar hot-water loop fluid, underfloor heating fluid, RV plumbing antifreeze, de-icing spray, and the drip tray under a motorcycle. A 1 L bottle that leaks 5-10 mL onto concrete is 2-5 lethal doses for a cat. Propylene glycol versions are far less toxic, but only if the label says so — never assume, and photograph the label instead of trusting memory.
Antifreeze is not the only household exposure with a short clock. The common toxic houseplants fill the same waiting room, and the toxicity checker covers the product name while someone else drives.
4 steps that take 10 minutes tonight
- Walk the garage, driveway and the shelf under the sink with a torch. Wipe any 1-2 mL puddle into a sealed bag and bin it.
- Move every container above 1.5 m, into a closed lidded bin, with a tray underneath each one.
- Photograph the label of every chemical you own, so a vet can read the concentration at 2 am without you spelling it.
- Save the clinic number and the 24-hour poison line under a name you will find while panicking, and keep a carrier by the door.
A cat with wet paws and a chemical smell has been exposed, even with no symptoms and no puddle you can find. Two milliliters is a small enough volume to hide in fur, and 30 minutes is a short enough window that driving now is always the cheaper decision.
Frequently asked
How much antifreeze will kill a cat?
Around 1.5 mL per kg is the usual minimum lethal figure, so roughly 4-5 mL for a 3 kg cat. Lapping is easy to underestimate, so any known exposure of 2 mL or more should be treated as an emergency and driven in, not watched.
Can I make my cat vomit at home after antifreeze?
No. Inducing vomiting is not a home measure for this poison: absorption starts within 30 minutes, the vomit risks landing in the lungs, and none of it removes what is already in the blood. The clinic can decide on lavage or charcoal, and only inside the first 30-60 minutes.
The cat looks normal 6 hours later. Can I wait until morning?
No. The 6-hour mark is the classic false recovery, when nervous signs fade while calcium oxalate crystals are already blocking the kidney tubules. Cats that go home at hour 6 often return at hour 24 with no urine, and that stage is far harder to treat.