ObjectiveTo explore the effect and mechanism of LQC on the immune function of B lymphocytes and NK lymphocytes in mouse with impaired immune function. Methods Mice with impaired immune function led by Cyclophosphamide (Cy)were used as experimental animmals, and divided into five groups randomly, twelve mice in every group, which is NS control group, Cy control group, Cy+ LQC minor and major dose group, and Cy + LQC decoction group. NS control group was given NS 0.2 ml/d subcutaneously 10 d, and the rest groups were given Cy 0.8 ml/d subcutaneously (20 mg/kg · d-1) 10d, to establish a mouse model of immune dysfunction. Since the 11th day each group was given NS, Cy, LQC minor dose, major dose and fructus ligustri lucidi decoctoin. Mice of each group were killed after 7 days. The percentage of B lymphocytes (CD3 - CD19 + ) and NK lymphocytes (CD3 - CD 16 + CD56 + ) in the peripheral blood of the experimental mice were detected by flow cytometer. ResultsIn comparison with LQC major dose group [ (20.44± 1.78)and(19.12± 1.70) ], fructus ligustri lucidi group[ (19.90± 1.42) and (20.17± 1.66) ], CD3-CD19+and CD3-CD16+CD56+ cells of LQC minor dose group[ (11.54±0.98) and (12.46±0.08)]were decreased significantly (P＜0.01), which were increased significantly compared with Cy group[ (4.53± 1.70) and (5.03 ±1.22) ] (P＜ 0.01), but they had no significant difference with NS [ ( 11.84 ± 0.99) and ( 12.90± 0.28) ] (P ＞ 0.05).In comparison with Cy group and NS group, CD3-CD19+ and CD3-CD16+CD56+ cells of LQC major dose group were increased significantly (P＜0.01), which had no significant difference with fructus lignstri lucidi group (P＞0.05). Conclusion The immune functions of the mice with impaired immune function were improved by LQC, it also could increase the quantity ofCD3-CD19+ cell and CD3-CD16+CD56+ cell. The dose of LQC was positively correlated with the modulation effect of LQC on the immune function.