The clinical condition of sepsis is caused by the release of numerous mediators from many cells. The purpose of this review is to describe the results of studies in which the role of free radicals and/or the potential therapeutic value of antioxidants are assessed. The studies described in this review come from a variety of sources, including Med-Line CD-ROM computerized database, Index Medicus, and references identified from the bibliographies of pertinent articles and books. Reports were confined to English language articles from 1966 to 1992. All retrieved references in which free-radical activity was assessed or antioxidants were measured or administered in sepsis or endotoxemia were included. This selection process encompassed clinical, animal and in vitro cell culture work. Cited literature was found in reputable peer-reviewed clinical or basic science journals. Any contradictions in the results of studies are discussed. There is evidence that free radicals play an important role in the pathogenesis of sepsis. Antioxidant therapy has the potential to protect against such injury. It is suggested that combination therapy, which augments the endogenous antioxidant defenses, is likely to be the best approach.