Abstract: OBJECTIVE To explore the effect of Bailing Capsules on interleukin-2(IL-2), complement and infection rate in patients with lupus nephritis. METHODS All of 120 patients with lupus nephritis were randomly divided into the observe group(n=60)and the control group(n=60). Patients in 2 groups all accepted the conventional treatment, while the patients in the observed group were given the treatment of Bailing Capsules (1g tid). The difference of clinical curative effect, infection rate, IL-2, complement 3(C₃) and adverse drug reaction were compared between the 2 groups after 12 months. RESULTS After 12 months, compared with the control group, in the observe group, the concentrations of IL-2, C₃ and serum albumin were significantly higher(P<0.05), and the concentration of urine protein, urine red blood cells and SLEDAI were significantly lower. The effective rate in the observe group(88.33%) was significantly higher than that in the control group(71.67%)(P<0.05). The infection rate during the 12 months follow up in the observe group(21.67%) was significantly lower than that in the control group(45.00%)(P<0.05). There was no significant difference of adverse drug reactions in the observe group(38.33%)and in the control group(36.67%). CONCLUSION Bailing Capsules could improve clinical curative effect and reduce the infection rate by adjusting the level of IL-2 and C₃, and didn’t increase in adverse drug reactions.