The aim of this study was to evaluate efficacy of extract from traditional Chinese medicine Zhuqin formula(ZQE)in cyclophosphamide-immunosuppressed mice.A total of 340 four weeks old Kunming mice were taken for the study.The study is divided into two parts.One part is tetermine a safe dose of ZQE by gastric perfusion in mice with an acute toxicity and a maximum tolerance test,and the second part of the presented study indicates the immunorestorative effects of ZQE dependent of the doses applied in mice treated with cyclophosphamide,including the carbon clearance index,the weight ratio of immune organ,serum hemolysin,T-,B-lymphocyte transformation rate and IL-2,IFN-γ,and IL-4 secretion.The acute toxicity test indicated that LD50 of ZQE by gastric perfusion in mice was > 5,000 mg/kg.The maximum tolerated dose of ZQE(oral administration)was > 120 g/kg.In thetreating immunosuppressed mice test,three doses of ZQE groups could increase the carbon clearance index,the weight ratios of spleen and thymus,serum hemolysin level,promote the secretion of IL-2,IL-4,and IFN-γ,and T-,B-lymphocyte transformation rate by 1.81-,1.73-,2.67-,2.36-,1.96-,and 2.69-fold of model group,respectively,and a 30mg/kg dose of ZQE presented a significantly better outcome,compared with the 40 and 20 mg/kg doses.