Many people use antifreeze—an additive that lowers the freezing point of a water-based liquid—to prepare their vehicles and homes for cold winter temperatures. While antifreeze is beneficial for preventing a vehicle’s engine from corrosion during freezing temperatures, this chemical’s active ingredient, ethylene glycol, is extremely toxic—and often deadly—to pets. Our Neighborhood Veterinary Centers of Nasa team provides you with the information you need to protect your pet from antifreeze poisoning. 

Why is antifreeze toxic to pets?

Ethylene glycol is the main ingredient in antifreeze. If your pet ingests ethylene glycol, their body quickly breaks down this chemical compound, which can cause calcium oxalate crystals to form in their kidneys, leading to acute kidney failure. Unfortunately, pets find this sweet fluid difficult to resist, and ingesting a small amount can be lethal. Only one to two tablespoons can be lethal to dogs. Only a teaspoon can be lethal to cats, who also have a poisoning risk if any part of their skin comes in contact with ethylene glycol, which is rapidly absorbed, affecting their kidneys, brain, and liver.

What products contain ethylene glycol?

Antifreeze is used as vehicle radiator coolant that regulates the engine’s temperature during extreme winter conditions. However, ethanol glycol is also an ingredient in many other household products, including:

  • Windshield deicer
  • Hydraulic brake fluid
  • Transmission fluid
  • Motor oil
  • Photo developing solutions
  • Solar water heaters
  • Wood stain
  • Paint
  • Snow globes
  • Freestanding basketball hoop bases

What are antifreeze toxicity signs in pets?

To ensure your pet’s positive outcome if they ingest antifreeze, learn to recognize early ethylene glycol poisoning signs. The longer this toxin is in your pet’s body, the more likely the outcome will be fatal. Learn to recognize the signs of ethylene glycol poisoning’s three stages:  

  • Stage 1 — Within 30 minutes of ingestion many pets initially act drunk and stumble. Initial signs may include lethargy, vomiting, incoordination, excessive urination, excessive thirst, hypothermia (i.e., low body temperature), seizures, and coma.
  • Stage 2 — Between 12 to 24 hours after ethylene glycol ingestion, some of a pet’s signs may seem to improve dramatically, and they may appear to behave normally. This can provide a false sense of security, because you may feel your pet is getting better, and you may delay having your veterinarian evaluate your four-legged friend and provide lifesaving treatment. 
  • Stage 3 — After 36 to 72 hours, severe kidney dysfunction signs—characterized by swollen, painful kidneys and minimal to no urine production—may occur, leading to progressive depression, lethargy, inappetence, vomiting, seizures, coma, and death. 

Ethylene glycol exposure requires aggressive medical treatment to ensure a pet’s survival. Any pet suspected of ethylene glycol exposure should receive veterinary care as soon as possible.

How is antifreeze toxicity treated in pets?

If your pet ingests antifreeze, their best chance for survival is to get them to an emergency veterinary hospital as quickly as possible. To be effective, antidotes, such as fomepizole (4-methylpyrazole [4MP]) or ethanol, must be administered as soon as possible. Left untreated, your pet may die. Your pet will likely need to be hospitalized for observation and 4-MP administration for 36 hours. Your veterinarian will also likely provide your pet intravenous (IV) fluids and additional supportive care to treat dehydration, electrolyte imbalances, vomiting, and nausea. Additional treatments may include:

  • Heart monitoring with an electrocardiogram (EKG)
  • Respiratory observation and monitoring
  • Regular temperature monitoring 
  • Medication to inactivate the ethylene glycol
  • Medication to treat tremors or seizures 
  • Medications to protect the gastrointestinal (GI) system
  • Blood and urine tests to evaluate kidney and liver function

How can I protect my pet from antifreeze toxicity?

You can take several steps to protect your pets from antifreeze poisoning. Follow these antifreeze safety tips:

  • Keeping containers tightly closed and out of your pet’s reach
  • Cleaning up spills immediately 
  • Regularly checking vehicle radiators for leaks 
  • Always supervising pets around vehicles and chemicals

Take precautions to protect your pet from antifreeze poisoning, ensuring they don’t come into contact with this toxic chemical. If your pet does manage to get into antifreeze, immediately contact our Neighborhood Veterinary Centers of Nasa team.