When small amounts (1 microgram) of lipopolysaccharide (LPS) purified from Salmonella minnesota (SM) wild, SM R60 and SM R345 were intravenously injected into mice 7 days after heat-killed Propionibacterium acnes was intravenously injected, massive hepatic cell necrosis was induced and most of the mice died within 24 hours. However, when LPS from SM R345 treated galactosidase, SM R5 and SM R7 and lipid A from SM R595 were administered, the survival rate was much higher and no histological changes of the liver such as necrosis could be seen in any of the mice. In each of the LPS used in this study, the structure of the polysaccharide chain was different and it was shorter in the following order: SM wild----SM R60----SM R345----SM R345 treated with galactosidase----SM R5----SM R7----SM R595. This suggests that the polysaccharide chain of LPS plays an important role in the induction of massive hepatic cell necrosis in this experimental model.