Multiple organ failure (MOV) still represents the leading medical and economical problem in the care of the critically ill surgical patient. Although the incidence of MOF has tended to decrease over the last several years reflecting improved surgical and supportive therapy in the ICU, prognosis still remains serious when MOF develops. MOF seems to reflect a dysregulation of host-defence systems, such as innate immune, coagulation and complement systems, which are likely to reflect a more general dysregulation of cellular and subcellular functions, such as signal transduction and stress gene expression. Besides complexity and redundancy of the mediator systems involved, their beneficial local reparative as opposed to detrimental systemic effects may have contributed to the disappointing results of anti-mediator strategies in the treatment of MOF and sepsis. Although treatment of the underlying disease remains the cornerstone of the care of the critically ill patient to prevent MOF, recent results indicating a decreased mortality in severely septic patients receiving activated protein C as a supportive treatment suggest that modulation of the mediator cascades of sepsis and MOF remains a generally promising therapeutic strategy.