Antifreeze Poisoning in Dogs

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What is Antifreeze Poisoning in Dogs?

Antifreeze poisoning is, unfortunately, one of the most common causes of poisoning in dogs. It is most often caused by the substance Ethylene Glycol, which is the antifreeze ingredient in 90% of antifreeze.  

Even small doses can be fatal for dogs. It’s an issue as it can sometimes be left in puddles or on the ground. The dog then may step in it and, after that, lick its paws, ingesting the antifreeze. Even worse is that most dogs find it tasty! So it is vital to know the symptoms of antifreeze poisoning and how to react if it does happen. 

Bottle of blue antifreeze, Antifreeze Poisoning in Dogs - I Love Veterinary

Why is Ethylene Glycol Poisonous for Canines?

When dogs ingest antifreeze ingredients like Ethylene Glycol, it can become fatal fast. Ethylene Glycol is broken down inside the body by chemical processes into the liver and kidneys into metabolites. These are what is toxic for the dog. 

These metabolites affect the liver, but especially the kidneys because they accumulate in there and damage them. 

The minimal lethal dose for dogs is:

  • 4.4ml/kg or just under 10ml/lbs. 

It is important to note that this amount will be lethal, but much smaller quantities can still make your dog very sick. 

Ethylene Glycol, Antifreeze Poisoning in Dogs - I Love Veterinary

Telltale Signs and Symptoms 

Symptoms of antifreeze poisoning in dogs are time and dose-dependent. It means that the larger the quantity ingested and the more extended period since ingestion will correlate with worse clinical symptoms. The faster the dog is seen by a veterinarian, the better the outcome will be! 

So if you in any way suspect that your dog has ingested antifreeze or are showing signs of antifreeze poisoning, give your vet a call, which is also why we often talk about the stages of poisoning. 

The Three Stages of Poisoning

Stage 1: 30 minutes to 12 hours 

Shortly after ingesting Ethylene Glycol, your dog will often start showing the following signs of antifreeze poisoning: 

  • Nausea (drooling is a sign of sickness). 
  • Vomiting. 
  • Increased thirst and urination. 
  • Trouble walking and appear to be “drunk.”

If enough Ethylene Glycol was ingested, even seizures, coma, and death could occur in this very first stage. 

Dog vomiting, Antifreeze Poisoning in Dogs - I Love Veterinary

Stage 2: 12 hours to 36 hours 

In this stage, your dog may experience the symptoms lessening. Giving many owners a false sense of recovery. Unfortunately, this is rarely the case. Instead, the lack of symptoms – or change in symptoms – means a further metabolization of the antifreeze. The most common symptoms in this stage are: 

  • Lack of appetite.
  • Only able to pass minimal quantities of urine. 
  • Heart rate increases.
  • Breathing rate increases.

Stage 3: After 36 hours 

In this stage, the kidneys start to fail. Symptoms in this stage can be: 

Coma and death may follow within a day of these symptoms appearing. 

One thing is clear: antifreeze poisoning in dogs is an emergency health issue. It needs to be taken seriously and seen by a veterinary professional as soon as possible. If you suspect your dog has ingested antifreeze, call an emergency veterinary service immediately. 

Antifreeze poisoning, microscope view, Antifreeze Poisoning in Dogs - I Love Veterinary
From Katie Miller: “Not the greatest picture, but we had an emergency come in that had been seizing for 1-2 days and no history of seizures… we ended up doing a UA and finding calcium oxalate mono hydrate crystals… my first antifreeze poisoning case as a technician assistant out of school!”

Available Treatment Options

Luckily there are some treatment options available for dogs that have ingested Ethylene Glycol from antifreeze. 

The goal is to prevent the absorption of Ethylene Glycol into the body. If the dog ingested the antifreeze within the last 30 minutes, induction of vomiting might be possible. The Ethylene Glycol still won’t have been absorbed and broken down by the dog’s body, which is why vomiting is an option. The dog might need to stay at the hospital for observation, but the prognosis is better. 

If more than 30 minutes have passed or symptoms have started showing, inducing vomiting will not help the dog. Instead, the aim of treatment is changed entirely towards preventing absorption and increasing excretion rates. 

The administration of fluids causes increased excretion. That also works to prevent dehydration of the animal. To prevent the metabolism of Ethylene Glycol, a product called 4-MP can bind and inactive some of the metabolites. The dosage for dogs is: 

  • 20ml/kg body weight. 

Meaning a lot of 4-MP will have to be administered – and fast! In dogs that have already reached the second stage of poisoning (12 to 36 hours after ingestion), 4-MP is likely to have little to no effect. Most of the Ethylene Glycol from the antifreeze will already have been absorbed and broken into its metabolites. 

For dogs in stage 2 or 3 of antifreeze poisoning, the prognosis is guarded to poor. It is possible to administer fluids to try and correct the electrolyte balance and maintain kidney function while increasing the excretion. 

Yellow antifreeze canister, Antifreeze Poisoning in Dogs - I Love Veterinary

Preventing Antifreeze Poisoning in Dogs 

Antifreeze and its active ingredients are very hazardous for our canine friends. One reason for this, of course, how it interacts within the body of our dogs, but also because: 

  • It is readily available: Almost everyone has antifreeze in their garage or house. 
  • Lack of information: Unfortunately, not owners are aware of the risks and symptoms of antifreeze poisoning. (But, you are off to a good start by reading this!)
  • It’s tasty: It has a sweet taste and smell (don’t test this statement at home!) that makes it appealing to many dogs once they get the antifreeze on their paws. 
  • It is hiding: Ethylene Glycol is a component of fluids in many products like solar collectors and radiator fluid. So remember to check the label when you buy those products and keep them out of reach from your dogs! 

Keeping it out of reach is the keyword for preventing antifreeze and Ethylene Glycol poisoning in dogs. Some sound advice for avoiding poisoning of our furry friends is: 

  • Keep antifreeze in a sealed and leak-proof container. 
  • Don’t pour used antifreeze on the ground. 
  • Consider non-poisonous alternatives to antifreeze with Ethylene Glycol. Antifreeze products with Propylene Glycol (similar name, less poisonous) and Glycerine are good options. 
  • If antifreeze is in the toilets, make sure you keep the bathroom door closed and the seat down. 
Dog in snow, Antifreeze Poisoning in Dogs - I Love Veterinary


Antifreeze and its compound Ethylene Glycol is poisonous and dangerous for our dogs; there is no way around it. However, it is also a useful and sometimes necessary product to get us two-legged ones (and our cars) through the winter! 

So keep an eye on puddles from your vehicle and be aware of the symptoms. Then you and your four-legged friend should be dashing through the snow in no time!

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With a veterinary master's degree from the University of Copenhagen in 2023, this accomplished writer's academic journey culminated in a thesis focused on the "Feasibility of using ultrasound of the abdomen for early diagnosis of necrotizing enterocolitis in neonatal pigs." Additionally, their dissertation delved into the intriguing topic of "Mercury accumulation in Greenlandic sleddogs." Beyond her academic achievements, her passion for animal health seamlessly merges with her love for writing. She excels in harmonizing clinical precision with literary expression, crafting articles that resonate with the heartbeat of her veterinary profession.