Antifreeze Poisoning in Dogs

dog on pavement looking up
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Many dog owners know that antifreeze is toxic to dogs, but not all people understand how dangerous antifreeze poisoning can really be. Unfortunately, exposure to even a small amount of antifreeze can quickly lead to death. Antifreeze poisoning in dogs is a very serious matter.

Antifreeze is a common hazard during winter, but dogs can easily be exposed to it any time of year. Dogs are most likely to be poisoned if they ingest it (though it technically can be absorbed through the skin).

 It is believed that dogs are attracted to antifreeze because it has a sweet taste. A dog may find antifreeze in storage areas but is not uncommon to find small puddles of it in driveways, garages and roadways. Be wary of puddles that have a greenish color or iridescent haze.

Some types of antifreeze are more toxic than others. Most brands contain the active ingredient ethylene glycol, which is also the most toxic. Antifreeze with the active ingredient propylene glycol or methanol is still toxic, but less so.

It takes very little ethylene glycol to poison a dog. Here is a breakdown of the toxic doses:

Toxic Doses of Ethylene Glycol in Dogs

(amounts are approximate)

  Dog's weight (lbs)    Toxic Dose (tbsp)
            10                      1-2
            20                      2-3
            40                      5
            60                      8
            80                      10-11

The Merck Veterinary Manual states: "The minimum lethal dose of undiluted EG is 1.4 mL/kg body wt in cats, 4.4 mL/kg in dogs, 7–8 mL/kg in poultry, and 2–10 mL/kg in cattle. Younger animals may be more susceptible."

Signs of Ethylene Glycol Poisoning

After exposure to ethylene glycol, most dogs begin showing signs very quickly.

At first, the signs may resemble alcohol intoxication. For the first 30 minutes to 12 hours after exposure, dogs often exhibit the following signs: 

  • Vomiting (due to GI irritation)
  • Lethargy
  • Drunkenness / ataxia / trouble walking
  • Increased thirst and/or urination
  • Excessive salivation
  • Sedation or stupor

After the first 12 hours, the above signs tend to subside. This may lead one to think the dog is improving. However, the toxin continues to do serious damage to the internal organs. 

Somewhere between 36 and 72 hours after intoxication, the dog's kidneys will begin to fail. At this point, the dog will again show signs of illness such as the following:

  • Lethargy
  • Loss of appetite
  • Vomiting
  • Diarrhea
  • Bad breath
  • Seizures

If aggressive veterinary treatment has not begun before this final stage, the chances of survival are decreased.

What To Do If Your Dog Gets Into Antifreeze

Unfortunately, ethylene glycol poisoning often leads to death. The sooner it can be detected and treated, the better chance the dog has for recovery. If you suspect your dog has been exposed to antifreeze, contact your veterinarian immediately. Do not induce vomiting unless your vet instructs you to do so. Do not just wait for your dog to show improvement.

Time is of the essence in order to prevent death.

Next: Here's How Vets Diagnoses and Treat Ethylene Glycol Poisoning in Dogs