A 1-year-old child with severe acetaminophen (APAP) poisoning after ingestion of 10 gm APAP demonstrated central nervous system depression, shock, hypothermia, and metabolic acidosis. There was dramatic improvement during treatment with intravenously administered N-acetylcysteine (NAC) and hemodialysis, and the patient recovered without sequelae. A detailed study of APAP metabolism was carried out during the initial 72 hours after ingestion. APAP-sulfate and APAP-glucuronide accounted for 29% and 33%, respectively, of total drug in urine, whereas cysteine and NAC conjugates accounted for only 12%. The low incidence of severe toxicity in children after overdoses of APAP may be related to greater capacity to metabolize APAP via a nontoxic pathway.