Five fatal cases of poisoning from ingestion of Amanita phalloides, a very common mushroom in central Italy, are reported. The fact that four of the cases occurred simultaneously enabled uniform collection of clinical, pathology and toxicology data, which is presented with particular emphasis on the histological aspects. The fifth case involved a six-year-old girl, and is discussed with reference to differential diagnosis with respect to Reye's syndrome, which was the initial diagnosis, demonstrated incorrect by the histology, pathology and toxicology findings. The typical liver and kidney alterations of Amanita phalloides poisoning, consisting of massive hepatic central lobular cell necrosis and acute tubular necrosis of the kidney are described. Outside the liver, there was often general hemorrhagic diathesis and severe brain edema. Although poisoning by Amanita phalloides is rare, these cases confirm the requirement for as complete a comparison as possible between circumstantial histopathological and toxicological data for the purposes of forensic diagnosis.