Objective To investigate the changes of plasma oxidized low-density lipoprotein (Ox-LDL) in endotoxemia mice and its effects on the inflammatory ability of lipopolysaccharide (LPS). Methods Endotoxemia model of 120 mice was duplicated with 1, 2.5 and 5 mg/kg of LPS intravenous injection respectively, and plasma Ox-LDL levels were assayed using ELISA kit at 0.5, 1, 2, 4, 8 h after LPS injection, and another 8 mice without any treatment served as normal control. Another 105 mice were divided into 3 groups pretreated with 0, 0.35 and 1.4 mg/kg of Ox-LDL intravenous injection 30 min before 1 mg/kg of LPS intravenous injection. Plasma TNF-? levels were measured with ELISA at 0, 1, 2, 4, 8 h after the first injection. The effects of Ox-LDL pretreatment on the mortality of another 150 endotoxemia mice 24 h after LPS injection was observed, which were treated with the same methods as 105 mice. Results Plasma Ox-LDL levels in endotoxemia mice increased significantly. In 0.5 to 8 h after LPS injection, plasma Ox-LDL levels were significantly higher than that of control group (P