Ethylene Glycol Poisoning in Cats

By Renee Schmid, DVM, DABVT, DABT; Ahna Brutlag, DVM, MS, DABT, DABVT; Kristiina Ruotsalo, DVM, DVSc, Dip ACVP; Margo S. Tant BSc, DVM, DVSc

What is ethylene glycol?

Ethylene glycol, a sweet-tasting, odorless liquid, is the active ingredient in most automotive antifreeze products. Ethylene glycol can also be found, in lower, less harmful, concentrations, in some windshield de-icing agents, hydraulic brake fluid, motor oils, solvents, paints, film processing solutions, wood stains, inks, printer cartridges, etc.

How do cats get ethylene glycol poisoning?

Cats may be attracted to ethylene glycol by its sweet taste. Many animals will voluntarily drink ethylene glycol if antifreeze is spilled or leaks onto garage floors or driveways. Ethylene glycol has a very narrow margin of safety – which means that a cat could easily drink a toxic dose. As little as one eighth of a teaspoon of undiluted antifreeze per pound of body weight can result in fatality.

What are the signs of ethylene glycol poisoning?

Ethylene glycol poisoning is divided into three stages.

Stage 1 (within 30 minutes to 12 hours of ingestion): The cat may appear “drunk.” Signs include lethargy, vomiting, incoordination, excessive urination, excessive thirst, hypothermia (low body temperature), seizures, and coma.

Stage 2 (12 to 24 hours after ingestion): Some of the signs seem to dramatically improve, luring pet owners into a false sense of security. However, during this stage, cats become dehydrated, developing an elevated heart rate and respiratory rate.

Stage 3 (12-24 hours after ingestion): At this stage, irreversible kidney failure may occur. Progressive depression, lethargy, lack of appetite, vomiting, seizures, coma, and death may be seen.

It is critical that you contact your veterinarian or Pet Poison Helpline, a 24/7 animal poison control center, at 1-800-213-6680 if you know or even suspect that your pet has consumed ethylene glycol, or if they are exhibiting any of the early symptoms. Do not wait; time is of the essence and immediate treatment is essential! Cats must be treated within 3 hours of ingesting antifreeze, as the antidote only has a short timeframe to work. Left untreated, the animal may die.

How do veterinarians confirm ethylene glycol poisoning?

The best way to confirm ethylene glycol poisoning is by measuring the blood concentration of ethylene glycol. This test can be performed at some veterinary diagnostic laboratories or human hospitals. This testing method is very accurate, but not always available in the middle of the night. Some veterinary hospitals have an in-house test kit that can detect the presence of ethylene glycol in the bloodstream. However, these types of tests may not be as accurate, and false positives can be seen (from exposures to other alcohols, such as propylene glycol, glycerol, mannitol, isopropyl alcohol, sorbitol, etc.). This test should be performed within 6 hours of exposure to ensure accuracy (could give a false negative). By as early as 24 hours after ingestion, insufficient ethylene glycol remains to allow detection on this blood test; however, the damage to your pet’s body from ethylene glycol has already occurred.

Are there other tests that can indicate ethylene glycol poisoning?

Ethylene glycol is converted by the liver into toxic byproducts that are damaging to the kidneys. This damage can be identified in a serum biochemistry profile, based on increases in the levels of creatinine and BUN (blood urea nitrogen) that are normally removed from the blood by the kidneys. However, these tests are not specific for ethylene glycol toxicity. Additionally, by the time these blood tests show evidence of kidney failure, the prognosis is grave to poor (since the damage is permanent). Acidosis (acidic blood) can be an earlier sign of toxicity. A urinalysis may also confirm ethylene glycol poisoning and underlying kidney damage by the presence of dilute urine containing blood, calcium oxalate crystals (which are seen with ethylene glycol poisoning) and other abnormalities. Lastly, a special black-light lamp (Wood’s lamp) can sometimes be used to examine the urine, muzzle, and paws of the patient to look for the presence of the warning dye which is added to automotive antifreeze.

When in doubt, if you suspect your pet has ingested ethylene glycol, seek immediate veterinary attention. The prognosis is very poor once clinical signs have developed. Again, because the antidote (fomepizole) is only effective if given within 3 hours of ingestion, it is imperative that you see a veterinarian immediately. When in doubt, you or your veterinarian can contact Pet Poison Helpline (800-213-6680) 24/7 for life-saving assistance in managing a poisoned patient.

Pet Poison Helpline, an animal poison control center based out of Minneapolis, MN is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s per incident fee includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at

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