Antifreeze Dangers

For a medium sized dog, ingestion of about 2 ounces (3-4 tablespoons) is toxic. For cats, as little as 1/4 of an ounce (1-2 teaspoons) can be lethal.

With the approach of winter most car owners will change out or add to the antifreeze in their vehicle's radiator, or use an antifreeze in their RV/camper drains or septic tank. The main ingredient in antifreeze is ethylene glycol, an extremely toxic poison that causes kidney failure which is often fatal in just a few days. Antifreeze has a sweet taste that dogs and cats like and if they find antifreeze they will drink it. Even a small amount of antifreeze can be fatal. If a cat walks through a puddle of antifreeze and then licks its paws, it can ingest enough antifreeze to cause death. About 3-4 tablespoons can kill a medium sized dog. If you see or suspect your dog has ingested antifreeze contact a veterinarian immediately, or rush your pet to an emergency vet clinic. In order to prevent the ethylene glycol from being absorbed into the liver your veterinarian will administer an IV of ethanol which counters the affect of the deadly ethylene glycol. The earlier treatment is started the greater the chance of survival. Once kidney failure develops, most pets will die.


The symptoms of antifreeze poisoning depend upon the time after ingestion. Symptoms can begin as soon as 30 minutes after the antifreeze has been ingested and may last about 12 hours.

The first symptoms are:
  • Appearing drunk
  • Depressed behavior (laying still or the pet has no interest in what is happening around it)
  • Frequent urination
  • Increased thirst
  • Staggering
  • Tremors or seizures
  • Vomiting
  • Wobbling
After the first stage the pet may appear to feel better but in a day or two get much worse as the kidneys begin to fail. The amount of urine passed will often decrease to a very small amount. At this point, the liver will have broken down the ethylene glycol, the active ingredient in antifreeze, changing it into more toxic substances. Further symptoms may not be noticeable for days and irreparable damage may be occurring. Vomiting may reoccur, as well as loss of appetite, dehydration, inability to urinate, salivation, seizures, mouth ulcers, coma and death. The diagnosis of antifreeze poisoning is made by blood and urine tests although some of these tests become negative by the time kidney failure develops.


Pets who suffer kidney failure due to antifreeze poisoning can occasionally be saved with aggressive treatment. Some specialty veterinary practices offer dialysis which can be used to remove waste products that are not being removed by the diseased kidneys in an effort to keep the pet alive in hopes of giving the kidneys a chance to repair. Whether the kidneys will repair themselves or not depends on how severely they are injured. Unfortunately the kidney damage caused by antifreeze is usually very severe and irreversible. Kidney transplants have been performed in dogs and cats but not all are good candidates for this type of surgery, and lack of donor organs may prevent those that are good candidates from having the surgery. This is an extreme measure and the expense is usually above what the average pet owner usually can afford.

Prevention Tips

When purchasing and using antifreeze, always keep the welfare and health of your pet in mind.

Keep both new and used antifreeze in a sealed container, out of reach of pets. Wipe any drips from the sides of the container before you store it. Properly dispose of all empty antifreeze containers and any rags used for wiping. Immediately clean up any spills of antifreeze on driveways and other hard surfaces. Antifreeze should never be drained onto the ground where it can leave a puddle. Another source of antifreeze are the decorative "snow globes" glassware. The liquid in the globes contain 2% antifreeze and is very toxic. There are several types of antifreeze on the market now that are propylene glycol based. Propylene glycol, although not entirely nontoxic, is considerably less toxic than the ethylene glycol based antifreezes.

There are several nationally available propylene glycol antifreezes on the market, including:
  • Sierra (Safe Brands Corp., 800-289-7234)
  • Sta-Clean (Sta-Clean Products, 800-825-3464)
  • Prestone LowTox® Antifreeze/Coolant - available at most automotive stores and department