What Happens if My Dog is Exposed to Antifreeze

Q: I hear conflicting stories about whether antifreeze is toxic to animals. It's time for me to change my car's coolant, and I have two dogs who like to "help" with my projects. How careful must I be? 

A: Standard antifreeze contains ethylene glycol, or EG, which is extremely toxic. Every year, EG poisons 10,000 dogs and cats, untold numbers of wild animals—and 5,000 humans, including hundreds of children. 

EG tastes sweet, so your dogs will be attracted to it. Keep them away from the area when you are changing your antifreeze, because just 3 tablespoons can kill a 25-pound dog. A cat can die after walking through a puddle of EG and licking it from her paws. 

Even dilute antifreeze is toxic, so if you spill it or see the telltale yellow-green puddle on the ground, don't hose down the area. Instead, sop up the antifreeze with paper towels, rags or cat litter. Seal the contaminated material in plastic bags, and discard them in a secure trash can. 

EG causes kidney failure. Clinical signs include vomiting, diarrhea, increased drinking and urination, disorientation, loss of coordination, rapid heartbeat, trouble breathing, seizures and coma. Without immediate treatment, EG poisoning is fatal. 

A safer alternative is propylene glycol, or PG, antifreeze. Popular brands are Sierra and Prestone LowTox. PG is added to foods, medications, artificial tears and cosmetics, although at very high doses, even PG can cause problems. So remember that while it's quite safe, it is still a chemical that should be handled cautiously. 

To keep your dogs and others safe, be very careful when you drain and dispose of your EG antifreeze, and consider replacing it with a much safer PG antifreeze. 

Editor’s Note: Falling temps and severe weather can impact your pet. Dr. Lee shares winter weather safety tips to help prepare dog parents. 

Lee Pickett, V.M.D. practices companion animal medicine in North Carolina. Contact her at vet@askthevet.pet.