In this research we proceeded experiments to find the basis which make it possible to explain the physical and pathological process of Sasang constitutional medicine, in the way substituting hematopoietic-immune system(essence of life, blood, Ki and mental faculties : 精血氣神) Under these suppositions, the essence of life(精) is the multipotent stem cell which has the possibility to be specialized to any cell, the Ki(氣), blood(血) and mental faculties(神) are inferred that they are formed from specialized the essence of life(精), the blood(血) is the red blood cells and etc. that appears as the result of the genesis of circulation system. The Ki(氣) is from specialized basic immunity, the mental faculties(神) means long-term memories or combined immunity. Cytokines can act as specilaizing, growing factors and particiate in extremly combined procedure being controlled by both positive and negative specializing signals. Blood gathering was carried out in the morning and on empty stomach. The plasma was seperated and Erythropoietin, Stem cell factor, Granulocyte-colony stimulaing factor, Tumor necrosis factor, interlukin-3, Interleukin-6 were measured with ELISA kit. According to the result of post analysis by Duncan, each constitution is different in SCF(stem cell factor), IL-6(interleukin-6), EPO(erythropoietin). The value of Stem cell factor is high in order of Soumin(少陰人), Soyangin(少陽人), and Taeumin(太陰人), The value of interleukin-6 is high in Taeumin, Soumin, and Soyangin. Erythropoietin is high in order of Soumin, Soyangin, and Taeumin.