The development and implantation of the ovum is closely related with the condition of endometrium. It has been considered that the histochemical study on the endometrial change during menstrial cycle is rather important than the pathologiacl investigation. In this connection, Nucleic acid (DNA & RNA), Polysaccharides and Alkaline phosphatase have been determined in 164 cases of nonmal human endometrium. 1) DNA level during menstrual cycle showed a incidence of the cyclic change. 2) RNA were shown markedly in the cytoplasma of the epithelium of endometrial gland and these levels were closely related with the cyclic change of endometrium. 3) Polysaccharides presented mainly in the epithelium and the cavity of endometrial gland, reached a maximum consentration in mid secretory phase. 4) Changes in Alkaline phosphatase level during menstrual cycle were preceded to the Polysaccharide change. 5) Alkaline phosphatase was found to the peak consentration at the ovulation, then decrea sed gradually.