Case Presentation: A 28-year-old male presented to the emergency department after an intentional ingestion of an unknown liquid in a suicide attempt. Urine obtained from the patient demonstrated green fluorescence under Wood’s lamp, supporting the diagnosis of ethylene glycol toxicity from antifreeze ingestion.

Discussion: Ethylene glycol is a toxic alcohol commonly found in antifreeze that causes multiple laboratory abnormalities, including elevations of anion gap, osmolar gap, and lactate [1,2,5]. Diagnosis can be difficult as many institutions lack a rapid or in-house serum ethylene glycol test. Most commercially available antifreeze solutions contain an additive that demonstrates green fluorescence under UV light, which can be picked up in the patient’s urine. Thus, when there is high clinical suspicion for ethylene glycol toxicity due to history and laboratory abnormalities, green urine fluorescence can support the diagnosis and lead to early intervention.

Keywords: Antifreeze; Ethylene glycol; Fluorescein; Toxic alcohol