Shock is the body's response to decreased cellular perfusion. It can begin with hemorrhage, mechanical obstruction of the circulation, cardiac dysfunction, central nervous system injury, or sepsis. Once triggered, shock is perpetuated by the release of toxic compounds from ischemic cells. The treatment of shock consists of the removal or correction of the triggering pathology, followed by resuscitation back to the normal state. Clinical research in shock resuscitation in the past year has focused on recognizing the presence of shock in patients at risk, particularly those with normal vital signs but ongoing, occult hypoperfusion. In the laboratory, the emphasis has been on minimizing the initial hemorrhagic insult, minimizing the release of toxins from ischemic cells, and blocking the response to the toxins that are released.