Objective To explore the possible mechanism of Runzaoling Decoction（ 润 燥 灵 方） in treating Sjogren’s syndrome（ SS）. Methods Ninety C57 mice were randomized into a blank group

a model group

a prednisone group

and low

medium and high dose Runzaoling Decoction groups

with 15 mice in each group. Each group was established SS mice models by immune induction method except the blank group. After the models were successfully established

the high

medium and low dose Runzaoling Decoction groups were given Runzaoling Decoction water decoction 36

18

or 9 g/（ kg·d）

respectively; the prednisone group was given prednisone 0. 2 g/（ kg·d）

the blank group and the model group given 0. 2 ml of normal saline

once every day. After 4 weeks of successive administration

the levels of serum interferonγ（ IFN-γ） and interleukin 4（ IL-4） were detected with Enzyme-Linked Immuno Sorbent Assay（ ELISA） method. The expressions of salivary gland T-bet and GATA-3 transcription factor were detected with polymerase chain reaction（ PCR） method. The number of serum Th1 and Th2 cells were calculated with flow cytometry. Results Levels of IFN-γ and IL-4

expression of T-bet

as well as T-bet/GATA-3

CD3+CD8-/IFN-γ

CD3+CD8-/IL-4 and IFN-γ/IL-4 in the model group were much higher than those in the blank group. Level of IFN-γ

T-bet expression

as well as CD3+CD8-/IFN-γand CD3+CD8-/IL-4 were lower in the High and medium dose Runzaoling Decoction groups

especially in the high dose Runzaoling Decoction group（ P < 0. 05 or P < 0. 01）. Conclusion Runzaoling Decoction might down-regulate serum levels of Th1/Th2 in SS model mice

which might be one of the mechanisms of treating SS.