To observe anti-inflammatory effect of Inula cappa aqueous extract on Klebsiella pneumoniae-induced severe pneumonia in rats.Methods:Klebsiella pneumoniae was used to induce ultrasonic severe pneumonia model in rats.Different doses of Inula Cappa aqueous extract (6,12 and 24 g/kg BW) were orally given,and take dexamethasone (1.04 mg/kg weight) as the comparison drug to conduct blood gas analysis,including peripheral white blood cells,neutrophils,TNF-alpha,IL-1 beta,IL-6,LDH and MPO activity in lung tissue.Results:Different doses of Inula Cappa aqueous extract can improve the arterial blood gas index,reduce the content of white blood cells and neutrophils,decrease the content of TNF-α,IL-1β,IL-6,MPO and level of NF-KBp65 and p-p38MAPK.Conclusion:Inula Cappa aqueous extract can improve inflammation of severe pneumonia induced by Klebsiella pneumoniae by blocking p38 MAPK and NF-KBp65 signaling pathways.It can be taken as a natural and effective anti-inflammatory drug.