A clinical study of acute gastrointestinal hemorrhage associated with various shock states. Gastrointestinal hemorrhage from stress ulceration is a life-threatening complication in a critically ill patient. We retrospectively studied 471 patients admitted to the Department of Traumatology of our hospital who developed shock in their clinical course. Forty-two patients (8.9%) developed gastrointestinal hemorrhage, most within 1 wk (76.2%). The hemorrhage lesion usually was located in the corpus of the stomach. The mortality rate of the shock patients with gastrointestinal hemorrhage was 33.3% (14 of 42). Comparison of different types of shock showed that the incidence, severity, and mortality rates of gastrointestinal hemorrhage were significantly higher in septic shock patients than in hemorrhagic shock patients. These findings show the importance of preventive therapy against progression of early mucosal damage and development of gastrointestinal hemorrhage in shock patients, especially those with sepsis. 