The subcommittee on Gastrointestinal Toxicology of the Patient Care Committee of the American College of Gastroenterology has reviewed potential effects of exposures to occupational and industrial hazards on the gastrointestinal tract, liver and pancreas. This review is presented to 1) share clinical data concerning gastrointestinal toxicology, 2) emphasize the paucity of available information to the practicing clinician, and 3) stimulate basic research interest in this field.