Methylchloroform (1,1,1-trichloroethane) is a widely used solvent substitute for carbon tetrachloride. Excessive absorption of methylchloroform through the gastrointestinal tract or lung produces central nervous system (CNS) depression proportional to the amount absorbed. Ingestion is followed by vomiting and diarrhea. Mild liver and kidney dysfunction may occur transiently following recovery from CNS depression. The diagnosis of exposure is established by specifically identifying the solvent in the expired breath. Serial breath analyses allow the estimation of the total amount absorbed. The treatment is supportive to combat the effects of CNS depression. The principles of diagnosis and treatment are illustrated by the case of a man, aged 47, who accidentally ingested one ounce of methylchloroform.