Sepsis is a highly lethal clinical syndrome characterized by a systemic inflammatory response to infection. Fever, a non-specific acute-phase response, has been associated with improved survival and shortened disease duration in non-life-threatening infections. However, the influence of fever and the effects of antipyresis in patients with sepsis has not been prospectively studied in humans. This paper reviews the state of our knowledge concerning the biological effects of fever in infected hosts and the influence of fever and antipyretic therapy on survival during sepsis in experimental models and in man.