Septic shock, acute respiratory distress syndrome, acute renal and hepatic failure, myocardial dysfunction, coagulopathy, encephalopathy:   these are some of the life-threatening responses to severe infection or traumatic injury facing patients and intensivists.   Alone and cumulatively, each of these conditions increases the risk of death even after successful treatment of the underlying infection or injury.   Mounting evidence points to the central role of the host's own inflammatory responses in the development of these syndromes.   Yet despite substantial effort, treatment approaches directed at a single mediator or inflammatory pathway have had little success in altering outcomes of critically ill patients.   It is clear that a more global understanding of complex biological systems is needed to advance care in this area and to reduce the currently substantial load of morbidity and mortality.   Genomic technologies offer the potential to move in this direction.