Objective To explore possible mechanism of Compound Shengdi Mixture（复方生地合剂） in treatment of systemic lupus erythematosus（SLE）. Methods Totally 30 MRL/lpr mice（lupus model mice） were randomly divided into model group

Compound Shengdi Mixture group and prednisone group

with 10 mice in each group

and 10 C57 BL/6 mice were considered as blank group. The Compound Shengdi Mixture group was given 2.8 g/ml Compound Shengdi Mixture with a human clinical equivalent dose of 18.495 ml/（kg·d） by gavage. The prednisone group was given 10 ml/（kg·d） 1.23 g/ml prednisone suspension by gavage. The model group and the blank group were given 10 ml/（kg·d） normal saline by gavage

once a day for each group. After 8 weeks of conti-nuous intragastric administration

interleukin-17 A（IL-17 A） and transforming growth factor-β1（TGF-β1） levels in serum were determined. Helper T cell 17（Th17） and regulatory T cell（Treg） levels in splenic lymphocytes

and mRNA expressions of retinoid acid orphan receptor γt（RORγt） and fox head box protein p3（Foxp3） in splenic tissue were determined. Death of the mice in each group was observed during the experiment. Results There were 2 mice dead in the Compound Shengdi Mixture group

1 in the prednisone group

3 in the model group and 0 in the blank group. Compared to the blank group

IL-17 A level in mice serum and the mRNA expression of RORγt in splenic tissue in the model group were increased; values of Th17/CD4

+

and Th17/Treg in splenic lymphocytes were also increased; TGF-β1 level in serum

the mRNA expression of Foxp3 in splenic tissue and the value of Treg/CD4

+

were decreased（P

<

0.05 or P

<

0.01）. Compared with the model group

the IL-17 A levels in mice serum

the mRNA expressions of RORγt

as well as values of Th17/CD4

+

and Th17/Treg in the Compound Shengdi Mixture group and the prednisone group were decreased

and the TGF-β1 level in serum and the value of Treg/CD4

+

were increased（P

<

0.05 or P

<

0.01）. There was no statistically significant difference in all indicators in the Compound Shengdi Mixture group and the prednisone group（P

>

0.05）. Conclusion Compound Shengdi Mixture can improve Th17/Treg balance in splenic tissue

which may be one of its mechanisms in treating SLE.