A fatal human infection with mesocercafiae of Alaria americana is described. Several thousand mesocercariae were estimated to be present in the peritoneal cavity, bronchial aspirate, brain, heart, kidney, liver, lungs, lymph nodes, pancreas, retroperitoneal adipose tissue, spinal cord, spleen, and stomach. Nine days from the onset of symptoms death resulted from asphyxiation due to extensive pulmonary hemorrhage probably caused by immun-mediated mechanisms. Circumstances suggest the victim probably ate inadequately cooked frog legs while hiking. Mesocercariae penetrated through the stomach wall and spread to the various organs both directly and via and circulatory system.