Objective To research the mechanism of Qingfei Oral Liquid for early respiratory syncytial virus（ RSV） pneumonia. Methods Totally 45 BALB/c mice were randomized into the blank group

model group

ribavirin group（ 0. 05 g /kgod ribavirin granules）

Qingfei low-dose group（ 37 g /kg·d Qingfei Oral Liquid） and Qingfei high-dose group（ 111 g /kg·d Qingfei Oral Liquid）

with 9 in each. Each mouse was given 50 ul RSV intranasally to make model in all groups except the blank group. The administration was started 48 hours after modeling. The pathological changes in the lung tissue were observed 24 hours later. The levels of interferon-γ（ IFN-γ）

T-bet

GATA3 and Th1 /Th2 were detected. Results Comparing with the blank group

the pathological scores were significantly increased but the levels of IFN-γ and Th1 /Th2 were significantly decreased in the model group（ P < 0. 01）. Comparing with the model group

the pathological scores were significantly decreased but the levels of IFN-γ and Th1 /Th2 were significantly increased in the ribavirin group and Qingfei high-dose group（ P < 0. 01）. Comparing with the blank group

the T-bet level was significantly decreased but the GATA3 level was significantly increased in the model group（ P <0.01）. Comparing with the model group

the T-bet level was significantly increased but the GATA3 level was significantly decreased in the ribavirin group and Qingfei groups（ P < 0. 01）. Conclusion Qingfei Oral Liquid is effective for early RSV pneumonia. It can inhibit inflammatory changes

which maybe relevant to reducing GATA3 level

increasing T-bet level

inducing IFN-γ expression and achieving Th1 /Th2 balance.