Lanthanum chloride has a certain role in medicine. For example, studies have shown that lanthanum chloride has an antagonistic effect on endotoxin (LPS) in vivo, which has a certain influence on the search for new effective endotoxin antagonists, and provides experimental basis for the prevention and treatment of endotoxemia. To observe the effects of lanthanum chloride treatment on the mortality of mice attacked by LPS 17.5mg/kg. To observe the effects of lanthanum chloride on plasma tumor necrosis due to α (TNF-α) and liver TNF-α mRNA expression, thymus cell apoptosis and liver and lung pathological injury of mice after LPS 12.5mg /kg attack. The results showed that the mortality rate of LMORtalized mice treated with 5, 10 and 20 mg/kg lanthanum chloride was 0, 0 and 8%, respectively, which was significantly lower than that of the control group (67%). After 10 mg/kg lanthanum chloride prophylactic administration, the mortality rate of mice attacked by LPS was 20%, which was significantly lower than that of the control group (55%). The plasma TNF-α content of lanthanum chloride treated mice with endotoxemia was 0.44± 0.215 ng/ml, and the mRNA expression of TNF-α in liver tissue was (3.9± 0.6)× 105 copies /μg RNA, which was significantly lower than that of mice with endotoxemia [0.99± 0.24 ng/ml]. (1.9± 0.3)× 107 copies /μg RNA]; The percentage of DNA fragments in thymus cells of mice with endotoxemia treated with lanthanum chloride was 30.35%± 6.42%, which was significantly lower than that of untreated mice (55.38%±3.88%). The apoptosis rate of thymocyte in endotoxemia mice was 15.56%± 0.59%, which was significantly higher than that in lanthanum chloride treated mice (6.05%±0.71%). Morphological examination showed that lanthanum chloride could alleviate the liver lung injury caused by endotoxin. Therefore, lanthanum chloride can bind LPS, reduce the toxicity of LPS, and have a protective effect on mice attacked by lethal amount of LPS. It can significantly reduce the secretion of TNF-α and the expression of TNF-α mRNA in liver tissue of mice with endotoxemia, inhibit the apoptosis of thymus cells, and alleviate the damage caused by LPS