BACKGROUND: Despite aggressive resuscitation shock often results in multiple-organ failure characterized by increased energy demands of organs and decreased ability of effective energy production. The administration of ATP-MgCl(2) as a supportive measure has been investigated in various animal models of ischemia/reperfusion injury and hemorrhagic, endotoxic, and septic shock. INVESTIGATIONS: These studies showed improvement in organ blood flow, microcirculation, energy balance, cellular and mitochondrial, functions and restoration of immune competence, ultimately leading to increased survival. Originally these effects were attributed to direct energy provision by the ATP-Mg complex, but the minute amount of ATP infused compared to the body's ATP formation rate suggests that other mechanisms must be responsible for its beneficial properties such as stabilization of the cell membrane, phosphorylation of membrane proteins, decreased cell swelling, and improved microcirculatory perfusion. CONCLUSIONS: The experimental evidence currently available suggests the use of ATP-MgCl(2) as a therapeutic adjunct in patients with multiple-organ dysfunction. In addition, given the extremely short half-life which allows both rapid titration and control of the systemic hemodynamic response, for example, reduction in mean arterial pressure, ATP-MgCl(2) may be suitable as an alternative to other fast-acting vasodilators used for the management of acute pulmonary hypertensive crises and/or for the maintenance blood pressure during aortic cross-clamping.