Objective: To evaluate the effect of Zhuchun pill (ZCP) on senile Kidney-Yang Deficiency (KYD). Methods: By single blind method, 45 elderly males with KYD were divided randomly into the ZCP group (treated by ZCP) and the control group (treated by placebo, starch capsule) and treated for 3 months.Results: ZCP could greatly improve the main symptoms of KYD, P < 0. 01 in comparison with the control group. After treatment, in the ZCP group, the 3H-TdR lymphocyte transformation rate, levels of serum C3,IgA, IgD, IgG and IgM, superoxide dismutase, plasma adrenocortical hormone, testosterone and cyclic adenosine monophosphate all increased, P < 0. 01, and plasma lipid peroxide decreased, P < 0. 01. While in the control group, no remarkable change was found in these parameters. Conclusion: ZCP could improve the KYD through regulating the immunity, endocrine function and scavenging the free radicals in organism. Objective: To evaluate the effect of Zhuchun pill (ZCP) on senile Kidney-Yang Deficiency (KYD). Methods: By single blind method, 45 elderly males with KYD were divided randomly into the ZCP group (treated by ZCP) and the control group treated by placebo, starch capsule and treated for 3 months. Results: ZCP could greatly improve the main symptoms of KYD, P <0.01 in comparison with the control group. After treatment, in the ZCP group, the 3H-TdR P <0.01, and plasma lipid peroxide decreased, P <0.01. The percentage of lymphocyte transformation rate in serum C3, IgA, IgD, IgG and IgM, superoxide dismutase, plasma adrenocortical hormone, testosterone and cyclic adenosine monophosphate all increased, While in the control group, no remarkable change was found in these parameters. Conclusion: ZCP could improve the KYD through regulating the immunity, endocrine function and scavenging the free radicals in organism.