Felis ISSN 2398-2950

Ethylene glycol poisoning

Synonym(s): Antifreeze; ethanediol

Contributor(s): Nicola Bates, Rosalind Dalefield, Myra Forster van-Hijfte


  • One of most common poisonings in cats.
  • Palatable, drunk willingly.
  • Signs: vomiting, ataxia, polydipsia, depression, coma, renal failure.
Treatment: ethanol, supportive fluid therapy.
Print off the owner factsheet Antifreeze (ethylene glycol) poisoning in your cat Antifreeze (ethylene glycol) poisoning in your cat  to give to your client.Follow the diagnostic tree for Evaluating Ataxia in Suspected Ethylene Glycol Toxicity Evaluating Ataxia in Suspected Ethylene Glycol Toxicity. 



  • Ethylene glycol consumed as concentrated solution of antifreeze or screenwash.
  • Often implicated in cases of malicious poisoning in cats.
  • Poisoning from drained vehicle radiator fluid.


  • Gastric irritant.
  • The metabolites of ethylene glycol are responsible for the severe effects seen with toxicity.
  • Rapid absorption from GI tract (peak plasma concentrations within 1 hour).
  • Absorption slowed by presence of food in gut.
  • Commonly reported lethal dose is 1.5 ml/kg in cats (much lower than in other species), but in another study 1 g/kg was fatal (NB 1 g/kg is approximately 1 ml/kg).
  • Metabolized in liver.  Glycoaldehyde   →   glycolate   →   oxalate.
  • Excreted via kidneys.
  • Aldehydes cause central nervous system (CNS) toxicity.
  • Glycolic acid causes metabolic acidosis.
  • Oxalate crystal formation   Urinalysis: calcium oxalate crystal  and glycolate   →   renal damage  Kidney: acute renal failure.
  • Metabolites cytotoxic to renal tubular cells.


  • Signs occur within 0.5-12 hours of ingestion.
  • Urinary excretion evident between 3-48 hours.
  • Acidosis can develop from 3 hours and is marked by 12 hours.
  • Elevation of urea and creatinine occurs from approximately 12 hours. 
  • 0.5-4 hours gastric irritation, ataxia and depression.
  • 4-24 hours tachypnea, depression and hypothermia develop due to severe acidosis.
  • If survives 12-24 hours oliguric renal failure.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Richards L, Ong H M, Davis M, Hodge P (2011) Ethylene glycol toxicity in a cat. Control & Therapy Series 263, 44-46.
  • Tart K M, Powell L L (2011) 4-methylpyrazole as a treatment in naturally occurring ethylene glycol intoxication in cats. J Vet Emerg Crit Care 21 (3), 268-272 PubMed.
  • Connally H E, Thrall M A, Hamar D W (2010) Safety and efficacy of high-dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats. J Vet Emerg Crit Care 20 (2), 191-206 PubMed.
  • Gaynor A R, Nishi Dhupa (1999) Acute Ethylene Glycol Intoxication. Part II. Diagnosis, Treatment, Prognosis and Prevention. Comp Contin Educ Pract Vet 21 (12), 1124-1133 VetMedResource.
  • Clark P, Henkel K, Swenson C (1997) What is your diagnosis? Ethylene glycol intoxication. JSAP 38 (10), 433, 450 PubMed.
  • Dial S M, Thrall M A, Hamar D W (1994) Comparison of ethanol and 4-methylpyrazole as treatments for ethylene glycol intoxication in cats. Am J Vet Res 55 (12), 1771-1782 PubMed.
  • Adams W H, Toal R L, Breider M A (1991) Ultrasonographic findings in dogs and cats with oxalate nephrosis attributed to ethylene glycol intoxication - 15 cases (1984-1988). JAVMA 199 (4), 492-496 PubMed.
  • Rowland J (1987) Incidence of ethylene glycol intoxication in dogs and cats seen at Colorado State University Veterinary Teaching Hospital. Vet Hum Toxicol 29 (1), 41-44 PubMed.
  • Thrall M A, Grauer G F, Mero K N (1984) Clinicopathologic findings in dogs and cats with ethylene glycol intoxication. JAVMA 184 (1), 37-41 PubMed.
  • Grauer G F, Thrall M A (1982) Ethylene glycol (antifreeze) poisoning in the dog and cat. JAAHA 18 (3), 492-497 VetMedResource.
  • Gessner P K, Parke D V, Williams R T (1961) Studies in detoxication. The metabolism of 14C-labelled ethylene glycol. Biochem J 79, 482-9 PubMed.

Other sources of information

  • Thrall M A, Connally H E, Grauer G F, Hamar D W (2013) Ethylene glycol. In:  Small Animal Toxicology.Eds: M E Peterson and P A Talcott. 3rd edn. St Louis, Missouri: Elsevier Saunders. 
  • Osweiler G D (1995) Toxicology. Philadelphia: Williams and Wilkins. ISBN: 0 6830 6664 1.