CONDITION
Ethylene Glycol Toxicity
Ethylene glycol toxicity occurs when a dog or cat ingests antifreeze or certain other products containing this sweet-tasting chemical. Once absorbed, ethylene glycol is metabolised in the liver into compounds that can cause severe damage to the kidneys, among other effects. The window between ingestion and the development of serious metabolic changes tends to be short, often measured in hours rather than days. Owners most commonly arrive at this topic after a known or suspected ingestion—perhaps antifreeze has been spilled in the garage, or a pet has been found near a puddle with a sweet smell. Early signs can include behaviour that appears similar to intoxication: unsteadiness, increased thirst, vomiting. Later signs may reflect worsening kidney function, though the progression and severity vary with the amount ingested and how quickly intervention occurs. This page explores the signs that may be observed, the metabolic processes that lead to kidney injury, how ethylene glycol exposure is investigated in practice, and the approaches used to interrupt the toxic pathway and support kidney function. The content is intended to help you understand what may be happening and what shape the conversations and decisions ahead might take.
Why this matters now
Ethylene glycol toxicity can occur at any age and affects both dogs and cats, though cats tend to require a smaller volume to produce severe effects. Exposure often happens in colder months when antifreeze is in use, or in settings where windscreen wash, brake fluid, or certain industrial products are accessible. The condition is not linked to breed, sex, or life stage—what matters is opportunity for ingestion and the appeal of the sweet taste.
The sequence of metabolic changes typically unfolds in stages over the first 12 to 72 hours, though the timing and severity vary with the amount ingested and the individual animal's metabolism. Early effects may appear within 30 minutes to a few hours and can include signs that resemble mild intoxication. As ethylene glycol is converted into toxic metabolites, the clinical picture often shifts towards metabolic disturbance and, in many cases, progressive kidney injury. The speed of progression means that the shape of the condition at 6 hours may differ markedly from what is observed at 24 or 48 hours.
Signals & patterns
Early signals
Unsteadiness or wobbly gait
Within the first few hours, a dog or cat may appear uncoordinated, as though slightly drunk—stumbling, swaying, or having difficulty walking in a straight line. This reflects the initial effects of ethylene glycol on the nervous system before metabolism into more harmful compounds has fully occurred.
Increased thirst and urination
Many animals begin drinking more water than usual and may urinate more frequently or in larger volumes shortly after ingestion. This can reflect the body's attempt to process and excrete the foreign substance, as well as early changes in how the kidneys handle fluid.
Vomiting
Vomiting may occur within the first few hours and can be a non-specific response to gastrointestinal irritation or the systemic effects of the toxin. The vomit itself does not typically have a distinctive appearance.
Lethargy or dullness
Some animals become quieter or less responsive than usual, seeming subdued or reluctant to interact. This may overlap with the period of apparent intoxication and can persist as metabolic changes develop.
Increased breathing rate
Faster or more effortful breathing can appear as the body begins to respond to metabolic acidosis—a shift in blood chemistry that the lungs attempt to correct by expelling more carbon dioxide.
Later signals
Reduced or absent urine production
After the initial period of increased urination, some animals may produce very little urine or none at all, reflecting worsening kidney function. This change often becomes apparent 24 to 72 hours after ingestion.
Weakness or collapse
As kidney injury progresses and metabolic disturbances accumulate, an animal may become profoundly weak, reluctant to stand, or unable to support its own weight. This reflects the systemic impact of failing kidney function and metabolic imbalance.
Seizures or twitching
In some cases, particularly in cats, neurological signs such as muscle twitching or seizures may develop later in the course. These can be linked to severe metabolic derangement, including low calcium levels and accumulation of toxic metabolites.
Click to read about the biological mechanisms
How this is usually investigated
Options & trade-offs
Last reviewed: Invalid Date ·