A case is reported in which progressive liver symptoms with rise in bilirubin concentration, hemorrhagic diathesis, and signs of portal hypertension developed three years before death in liver coma. The pathologic and neuropathologic findings are described. The case was clarified after dimethylnitrosamine was demonstrated in food intended for the patient and after it was established that small amounts of nitrosamine could have been repeatedly ingested by the patient over a period of years. Comparable cases of human dimethylnitrosamine poisonings published in the literature are presented. The relatively typical morphologic alterations in the liver are described. Problems involved in the histological interpretation of such liver changes as well as the forensic conclusions to be drawn are discussed.