Endotoxin, a class of lipopolysaccharide molecules derived from the gram-negative bacterial cell wall, consists of three regions: the O-specific polysaccharide, the core polysaccharide, and the lipid A (1). The O-specific polysaccharide, which carries the primary antigenicity of the bacteria, is linked to the core polysaccharide that is common to varieties of bacteria. The latter is bound to lipid A, which possesses most of the biologic activities of endotoxin. Endotoxin stimulates many pathophysiologic responses, including fever, activation of the immune system and the complement cascade, disseminated intravascular coagulation, and disturbances in glucose and lipid metabolism.