Two otherwise healthy 16-y-old female patients were treated with sodium bicarbonate and ethanol after the ingestion of unknown quantities of ethylene glycol. Patient 2 was admitted twice for ethylene glycol poisoning in unrelated events. In patient 1, the maximum levels of ethylene glycol and glycolate in plasma were 14 mmol/L (0.9 g/L) and 8.2 mmol/L (0.5 g/L), respectively. In patient 2, the maximum levels of ethylene glycol in plasma during the 2 admissions were 18 mmol/L (1.1 g/L) and 45 mmol (2.8 g/L), respectively. In patient 1, a blood ethanol concentration between 130-140 mg/dL (28-30 mmol/L) was reached 3 h after the start of ethanol administration and maintained for 22 h. During this period, ethylene glycol metabolism was effectively inhibited as indicated by S-glycolate levels and that 88% of the eliminated ethylene glycol was accounted for in the urine. This suggests that ethanol therapy alone may be sufficient for patients admitted early with low serum ethylene glycol concentrations. During the admissions of patient 2, the blood ethanol concentrations were presumed to effectively inhibit ethylene glycol metabolism as judged from normal acid/base parameters. However, during the second admission the bolus infusion of ethanol was associated with respiratory arrest. During both admissions for patient 2, hemodialysis constituted the major route of ethylene glycol elimination.