The development of methods for the analysis of gene structure and function, referred to as recombinant DNA (deoxyribonucleic acid) technology, has created unprecedented opportunities for significantly improving the prevention or treatment of human diseases. Both practitioners working in this field and interested observers cannot fail to recognize that the remarkable progress in understanding disease pathogenesis has placed us on the threshold of a new, revolutionary era of clinical practice. In this context, molecular medicine--that is, the application of molecular biology to elucidating the causes and potential cures of disease, has become a major thrust of research at virtually all medical schools. Incorporating the techniques of molecular biology into the research arsenal of the physician should provide new opportunities to dissect out and define the reversible and irreversible intracellular processes giving rise to acute respiratory distress syndrome, sepsis, septic shock, or multiple system organ failure, the major causes of mortality in most intensive care units.