Abstract: OBJECTIVE To observe the interventional effect of houttuynia cordata extract on rats with Klebsiella pneumoniae pneumonia. METHODS Totally 120 SD rats were enrolled in the study and divided into the control group with 20 rats, the infection group with 34 rats, the infection plus low-dose group with 33 rats and the infection plus high-dose group with 33 rats. The rat models were established, the rat models of 30 rats that were established successfully in the infection group, the infection plus low-dose group and the infection plus high-dose group were treated with gavage. The body weight, lung weight, lung wet mass index, expression level of death-associated protein kinase 1（DAPK1）, expression levels of interferon-γ（IFN-γ）and interleukin-6（IL-6） and the relative expression levels of Toll-like receptor 4（TLR4） and nuclear transcription factor-κB（NF-κB） were observed. RESULTS The body weight and lung weight of the infection group, the infection plus low-dose group and the infection plus high-dose group were less than those of the control group; while the lung wet mass index, DAPK1 expression level and relative expression levels of IFN-γ, IL-6, TLR4 and NF-κB of the infection group, the infection plus low-dose group and the infection plus high-dose group were higher than those of the control group（P＜0.05）. The body weight and lung weight of the infection plus low-dose group and the infection plus high-dose group were greater than those of the infection group, while the lung wet mass index, DAPK1 expression level and relative expression levels of IFN-γ, IL-6, TLR4 and NF-κB of the infection plus low-dose group and the infection plus high-dose group were lower than those of the infection group（P＜0.05）. The body weight and lung weight of the infection plus high-dose group were greater than those of the infection plus low-dose group, while the lung wet mass index, DAPK1 expression level and relative expression levels of IFN-γ, IL-6, TLR4 and NF-κB of the infection plus high-dose group were lower than those of the infection plus low-dose group（P＜0.05）. CONCLUSION Houttuynia cordata extract may reduce the levels of DAPK1 and inflammatory factors of the rats with pulmonary infection, and the mechanisms of action may be associated with the TLR4/NF-κB pathways.