Hemorrhage and sepsis may lead to multiple organ system failure caused by a redistribution of cardiac output and a reduction of tissue perfusion. The pathophysiologic changes caused by hemorrhage are frequently prevented by rapid diagnosis of the cause of the bleeding (e.g., vessel injury or coagulation disorder) and its therapy. The pathophysiologic changes in sepsis are mediated by toxins which affect almost every organ system. Knowledge of the predisposing factors, rapid recognition of signs and symptoms, and understanding of the underlying pathobiochemical and pathophysiologic changes are mandatory in the successful therapy of septic shock. The main therapeutic principle remains removal of the focus.