Objective: To investigate the clinical effects of modified Zhibai Dihuang decoction for patients of systemic lupus erythematosus (SLE) with Yin deficiency. Method: Ninety-eight patients of active SLE with Yin deficiency were randomly divided into two groups.Fifty-two patients in treatment group were treated with modified Zhibai Dihuang Decoction combined with conventional glucocorticoid treatment for 12 weeks

while 46 cases in control group received conventional glucocorticoid treatment

when glucocorticoid showed invalid cyclophosphamide therapy was given. Systemic lupus erythematosus disease activity index (SLEDAI)

serum complement (C3 and C4)

circulating immunocomplex (CIC) and consumption of hormones were investigated before and after the treatments. Result: After treatment for 8 weeks and 12 weeks

the scores of SLEDAI of treatment group were lower than that in the control group (P<0.05

P<0.01); C3 and C4 value of control group were lower than those before treatment (P<0.05)

but those in the treatment group did not change significantly. In both groups

CIC was higher after treatment (P<0.05)

the increase in the control group was more significant (P<0.01). The daily and the total consumption of prednisone in the treatment group was less than those in the control group (P<0.05

P<0.01). Conclusion: Combination of modified Zhibai Dihuang decoction with western medicine is more effective compared with western medicine alone for treating active SLE patients with Yin deficiency. The combined therapy can improve the immune system

reduce the amount of glucocorticoids.