If you are looking to book a cat vaccination, please be aware that there is an ongoing shortage of some cat vaccines affecting all UK Veterinary practices. Find out more here.

Dangers of Antifreeze

Poisoning to our Pets

Worryingly, many commercial Antifreeze mixes still do contain Ethylene Glycol. This is one of the most dangerous household poisons, and its ingestion is frequently fatal in both cats and dogs.  

Cats and young puppies are at a particularly high risk. 

Sadly, Antifreeze poisoning it still encountered over the colder, winter months. Please do be aware of this potentially fatal poison, particularly so if yourself, or your neighbours' own cats, who are more likely to "roam". 

Ethylene Glycol is apparently sweet tasting, which means that pets are much more likely to have a fatal exposure. It has the highest fatality rate of all known veterinary poisons.  

Ethylene glycol is found in many “antifreeze” products. These are frequently used in car radiators and engines, hydraulic brake fluids and in some screen washes and de-icers to prevent freezing.  

Toxicity is directly related to the ingestion of the ethylene glycol, which is the principal component (95 percent) of most antifreeze solutions.  

Antifreeze is unusually recognisable by its bright green colouring. Even very small amounts can be fatally toxic to body organs, including the brain, kidneys, and liver.   

Pets generally encounter antifreeze when it leaks from a car's engine onto the ground, when it is spilled onto the ground while being added to a car's engine, if there are spillages directly from the container or when the refill container is left uncapped.   

Pets appear to like the apparent “sweet” taste of antifreeze, so they may lap it up and ingest it from puddles or from any spillages. Cats may also ingest it by licking and grooming themselves after simply walking through any spillages. It is extremely toxic to cats, and they only need to drink a teaspoon or less of antifreeze for it to cause serious illness and even death.  

Horrifically there have also been some cases of malicious poisoning of cats with antifreeze. Under the Animal Welfare Act 2006, this is a criminal offence. The maximum penalty for anyone found guilty of this horrendous crime is up to six months in prison, and/or a £20,000 fine.   

Symptoms of poisoning are dependent on the amount of ethylene glycol ingested. The symptoms and signs of poisoning are caused by the ethylene glycol itself and the toxic metabolites produced by the body's chemical processes as it breaks the ethylene glycol down. These symptoms of organ poisoning sadly are frequently fatal.   

The poisoning effect has several stages. About 30 minutes after ingesting the poison Ethylene glycol starts to alter brain function. Its effects are similar to ingesting alcohol, causing an altered mental state, often with initial excitement followed by depression, weakness, stupor or a coma. There usually is wobbliness and difficulty in balancing, head tremors, followed by a loss of reflexes. Nausea and vomiting follow, often with an initial increased urination. 

Most dogs will appear to apparently transiently “recover” from this “drunkenness”, and often can seem to be virtually normal by about 12 hours after ingestion.  Cats, on the other hand, stay lethargic, sleepy, depressed or even unconscious, and usually, do not show this transient “recovery”. 

However, after 12 hours a later toxicity causes kidney failure. The real concerns with ethylene glycol is that it is broken down in the body into glycolaldehyde, which is extremely toxic to kidney tissues. Initially, the amount of urine production initially increases, but then it starts to decrease sharply. This decreased urination is often the first sign that serious, and usually permanent, kidney damage has occurred. In dogs, signs of kidney damage usually start about 36-72 hours after ingestion. Cats are more rapidly affected, with kidney symptoms starting at about 12-24 hours after poisoning. 

Blood and urine sample tests will show abnormalities consistent with ethylene glycol toxicity, such as kidney damage and certain crystals in the urine. Symptoms of Kidney damage are: Nausea and vomiting; Dehydration; A strange, metallic smell on the breath; Collapse; seizure; Coma and ultimately Kidney failure and death. As the kidneys fail, they are unable to remove waste products and damaging toxins from the bloodstream, resulting in a toxic, “uraemic syndrome”. The less urine the patient can make, the worse the prognosis for the case. Cats and puppies usually suffer worse than adult dogs. Any animal that shows little or no urine production are sadly unlikely to recover, even with intensive treatments. 

Ethylene glycol toxin is rapidly absorbed through the stomach wall. The main aim of any attempted treatments is to slow down the conversion of ethylene glycol into the more toxic glycolaldehyde. There are drugs available to try to achieve this, which require intensive care and hospitalisation for several days, and treatment must be started as soon as possible.   

Sadly, once kidney failure is noted, most affected patients will die. In animals that do survive the kidney failure stage, most will have lifelong kidney problems. Tragically, even with prompt veterinary treatment, ethylene glycol poisoning is often fatal in most cases.    

So, if you have any products in your home or garage containing ethylene glycol such as antifreeze, then please make sure you store them safely away all animals, and from children. Even safer, you can now choose screen wash and de-icer products that do not contain ethylene glycol at all.  

If a car radiator has been drained and a splash of antifreeze remains on the garage floor or driveway, then wipe up the spillage completely and immediately and rinse the area thoroughly with water. Remember even a tiny amount of ethylene glycol on a cat’s feet, picked up if it walks through any spillage, is enough to cause some harm. Please keep all Antifreeze products well out of reach and carefully mop up carefully after any spillages. Also be aware that some "path salt" products may also contain Antifreeze, so as a precaution wipe down your pets’ feet with plenty water after walks on “salted” pavements and roads. 

If you think your pet may have ingested anything containing antifreeze, contact your Vet clinic for emergency assistance immediately. 

Alison Laurie-Chalmers
Senior Consultant
Crown Vets 

Return to Alison's Articles