Sijunzi decoction, Siwu decoction and Bazhen decoction can antagonize the suppressive effect of hydrocortisone on proliferation of lymphocyte by spleen cells in C57BL/6J mice in vitro, and of the three decoctions Sijunzi works best. Sijunzi Decoction can antagonize the suppressive effect of cyclophosphamide on the delayed cutaneous hypersensitivity (DCH) induced by DNCB in mice and the production of hemolysin in mice immunized with SRBC. The three prescriptions all can enhance the clearance rate of iv charcoal particles as well as bone marrow cells inhibited by cyclophosphamide in mice, but Sijunzi decoction functions best of all.