A 19-year-old woman was admitted 45 min after ethylene glycol (EG) ingestion. The initial serum EG concentration was 1.34 g/l (21.6 mmol/l), the anion gap 14.5, and the osmolal gap 24. Renal function was preserved (serum creatinine 75.1 micromol/l). As the patient was seen soon after poisoning, before the development of metabolic acidosis, therapy with 4-methylpyrazole (4-MP) was proposed as an antidote. 4-MP was administered via the intravenous route (7 mg/kg as loading dose, followed by 3.6, 1.2, 0.6, and 0.6 mg/kg at intervals of 12 h). 4-MP alone was effective in preventing EG biotransformation to toxic metabolites (absence of metabolic acidosis and renal injury). Ethanol therapy, hemodialysis, and sodium bicarbonate administration were not required. The half-life of EG during 4-MP therapy was 11 h, with a mean EG renal clearance of 26.9 ml/min, and a total of 65.3 g EG was eliminated unchanged in the urine. 4-MP therapy was also well tolerated.