Objective: To observe the effect of compound Codonopsis Radix extract on immunological function in immunosuppressive model mice induced by cyclophosphamide. Method: The immunosuppressive model in mice was induced by cyclophosophamide. Mice were administered with (low

medium and high dose

0.25

0.5 and 1.0 g ·kg-1 accordingly) compound Codonopsis Radix and control groups were administered with distilled water for 10 days. MTT assay was employed to evaluate the metabolic activity of splenocytes.The changes in the phagocytotic activity of macrophage in response to compound Codonopsis Radix extract treatment were tested by phagocytosis percentage of chicken red blood cells (CRBCs).The effect of compound Codonopsis Radix extract on humoral immunity was assessed in mice immunized with sheep red blood cells (SRBCs) by measuring the serum levels of specific antibody against SRBCs. Result: Compound Codonopsis Radix extract significantly increased the paw swelling in mice

enhanced the metabolic activity of mouse splenocytes

and also significantly increased serum hemolysin level immunized with SRBCs and capacity of mouse peritoneal macrophages for CRBC phagocytosis in mice induced by cyclophosophamide. Conclusion: Compound Codonopsis Radix extract can stimulate the immunologic function in immunosuppressive mice.