Is antifreeze toxic to dogs?
Yes, antifreeze containing ethylene glycol is severely and rapidly toxic to dogs. Even a very small amount, such as a few licks from a puddle, can cause irreversible kidney failure and death. Its sweet taste makes it attractive to animals, increasing the risk of accidental ingestion.
Antifreeze is dangerous because the liver metabolizes ethylene glycol into toxic byproducts. These substances form crystals in the kidneys, causing acute kidney shutdown within 24 to 72 hours. Some poisonings show signs later than this. If in doubt, call your vet. Due to the rapid progression and narrow treatment window, any suspected exposure is a life-threatening emergency.
Toxic dose by dog weight
Merck describes an approximate lethal oral dose of 4.4–6.6 mL/kg of undiluted ethylene glycol in dogs. A lethal observation is not an intervention threshold or a safe allowance. The ingredient and concentration matter, and any suspected ingestion needs immediate veterinary care. Do not use an approximate teaspoons conversion to delay treatment.
Published dose reference: Merck Veterinary Manual — ethylene glycol toxicosis; Pet Poison Helpline — Antifreeze.
Symptoms timeline
Symptoms of ethylene glycol poisoning occur in stages. The window for effective treatment is very narrow, typically within 8 hours of ingestion, before kidney failure begins.
- Stage 1 (0-12 hours post-ingestion): The dog will appear 'drunk.' You may see wobbliness (ataxia), stumbling, nausea, vomiting, and increased thirst and urination. The dog may seem to recover temporarily during the latter part of this stage, which can be misleading for owners.
- Stage 2 (12-24 hours post-ingestion): The initial neurological signs may seem to resolve, but severe internal damage is occurring. The dog may become lethargic and dehydrated, with a rapid heart rate (tachycardia).
- Stage 3 (24-72 hours post-ingestion): This stage is characterized by severe acute kidney injury. The kidneys will stop producing urine. Symptoms include severe lethargy, depression, loss of appetite, vomiting, seizures, and coma.
What to do right now
IMMEDIATE action is required. Antifreeze poisoning is a life-or-death emergency with a very short treatment window.
- Call a veterinary professional immediately. Either your local veterinarian, an emergency animal hospital, the ASPCA Animal Poison Control Center (APCC), or the Pet Poison Helpline.
- Do not wait for symptoms to appear. By the time symptoms are obvious, the window for the most effective treatments may have closed.
- Do not induce vomiting unless specifically instructed to do so by a veterinary professional. The rapid absorption of ethylene glycol makes this of limited use and can be dangerous.
- If possible, bring the antifreeze container with you to the veterinarian. This will help them confirm the toxic ingredient and calculate the potential dose ingested.
When to call a vet
Contact a veterinarian or poison control hotline immediately if:
- You know your dog ingested antifreeze.
- You suspect your dog may have licked or drunk any amount of antifreeze.
- You find a chewed or punctured antifreeze container.
- Your dog is showing signs of being 'drunk,' wobbly, or is suddenly vomiting.
How antifreeze compares to other common toxins
Ethylene glycol is considered one of the most severe and rapidly acting poisons a dog can encounter, largely due to the sweet taste and the very small lethal dose. Unlike chocolate, where a large quantity is often needed to cause severe signs, a few licks of antifreeze can be fatal. Compared to a toxin like grapes or raisins, which causes kidney failure in some dogs through an unknown (idiosyncratic) mechanism over a longer period, antifreeze has a clear, dose-dependent, and rapid progression to kidney failure in all dogs.