Systemic inflammatory response syndrome is a term used to describe the host's response to infection or diffuse tissue injury characterized by the release of various proinflammatory and antiinflammatory mediators. The local release of inflammatory mediators is critical in the development of a systemic inflammatory response. If the initial response is balanced and contained, homeostasis is preserved. However, if either response is excessive, systemic involvement and end organ damage occur. Understanding the relationships between the initiators and secondary mediators generated in response to inflammation improves our understanding of the clinical syndrome associated with infection and progressive multiple system organ dysfunction. It also creates a potential role for the use of cytokines in early diagnosis of infection and development of targeted therapeutic strategies to attenuate the systemic inflammatory response and improve clinical outcome. Copyright © 2001 by W.B. Saunders Company