Objective To explore the possible mechanism of Sanren Tang（ 三仁汤） in preventing and treating respiratory diseases under damp-heat circumstances. Methods Seventy-two mice were randomized into blank group

model group and Sanren Tang group

with 24 mice in each group. The blank group was fed under conventional environment

while the other two groups were put into climate chamber with high temperature and high humidity. The Sanren Tang group was given Sanren Tang（ 1 g/ml 0. 2 ml） by gavage before and at the 12 th hour of being put into climate chamber. The blank group and model group were given equivalent normal saline by gavage. At the 12 th

24th hour and on the 4th day after being put into climate chamber

eight mice in each group were selected to draw materials

and the levels of mucin 5AC（ MUC5AC）

aquaporin 1（ AQP1） and aquaporin 5（ AQP5） were detected.Results The 24th-hour MUC5 AC level in the model group was higher than that in the blank group; the MUC5 AC level at the 12 th and the 24 th hour in Sanren Tang group was respectively lower than that in the model group（ P <0. 05）. In Sanren Tang group

the AQP5 level at the 12 th and the 24 th hour was significantly higher than that in the blank group

and at the 24 th hour

it was higer than that of the model group（ P < 0. 05）. On the 4th day

there was no significant difference of MUC5 AC level and AQP5 level among groups（ P > 0. 05）. In each group

there was no significant difference of AQP1 level at different time points（ P > 0. 05）. Conclusion By promoting the expression of AQP5 in lung tissue

Sanren Tang may inhibit the secretion of MUC5 AC

and prevent the airway mucus hypersecretion in respiratory diseases under damp-heat circumstances.