Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Warning to Pet Owners: The Dangers of Antifreeze Poisoning


Pet Column for the week of December 17, 2001


Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Jennifer Stone
Information Specialist

For household pets winter weather brings a deadly threat that comes in a plastic bottle. It is ethylene glycol, a chemical commonly used in antifreeze. Dr. Petra Volmer, a veterinary toxicologist at the University of Illinois College of Veterinary Medicine, says, "Antifreeze is said to be sweet and animals like to eat it. But ingestion of antifreeze can be fatal if untreated."

Ethylene glycol is metabolized by the liver and travels in the bloodstream to the kidneys, where it forms insoluble calcium oxalate crystals inside the renal tubules. Dr. Volmer says, "Once metabolism of the ethylene glycol has reached a certain point, there is no way to stop it." Because these crystals are insoluble, there is no way to remove them from the body. They cause permanent damage to the kidney tissue, which can ultimately lead to kidney failure.

An animal that has ingested ethylene glycol must receive immediate medical attention. Those caught in the act of drinking the antifreeze have the best chance of survival because medical attention can be administered immediately.

Initial signs of antifreeze poisoning are depression and lethargy. Animals may seem groggy or drunk. The final stages of poisoning are characterized by vomiting, oral and gastric ulcers, and renal failure, followed by death. The initial signs can last from 1 to 6 hours and death may occur between 3 to 4 days

If an animal is showing signs of antifreeze poisoning, but the owner did not see the animal drink it, there is a test kit available to veterinarians detect the presence of the poison in the body. However, cats are especially sensitive to ethylene glycol and can experience toxic effects from a dose lower than that required for a positive result from the test.

Most antifreeze products that contain ethylene glycol have a fluorescent dye added so they glow under a special fluorescent light called a Wood's lamp. If antifreeze poisoning is suspected, a quick and inexpensive way to determine if antifreeze was ingested is to have your veterinarian shine the light on the muzzle, paws, and under the tail of the animal. If antifreeze residue is present, the hair will glow. Avoid shining the light into the eyes of the animal.

Treatment for ethylene glycol poisoning can be expensive and can require extended hospitalization. In addition, treatment is not always successful if the product has been metabolized. For this reason, prevention is essential. Regardless of what kind of antifreeze you use, it is important to keep pets out of it. Watch for leaks in your car and keep pets away from the area where antifreeze is stored. If you drain your antifreeze, do not leave it in an open container because animals will be attracted to it. Dispose of this waste properly and keep empty and full antifreeze containers away from dogs, who may be tempted to chew on them. Even people who do not have pets should follow these rules to avoid accidentally poisoning wild animals and pets belonging to other people.

There are newer brands of antifreeze on the market that use propylene glycol instead of ethylene glycol. Propylene glycol is commonly found in such products as lotions, creams, and toothpaste and is not as toxic as ethylene glycol. If at all possible, it is best to choose an antifreeze that does not contain ethylene glycol.

By following these simple safety tips you can help ensure that you pet has a healthy winter. If you have any questions regarding antifreeze poisoning, please contact your local veterinarian, or call the ASPCA Animal Poison Control Center at 1-888-426-4435 for 24 hour consultation with a veterinarian trained in toxicology.