<；P>；PROBLEM TO BE SOLVED: To provide a method for efficiently proliferating the stem cells of a mammal under the maintenance of the undifferentiated state of the stem cells and preparing the stem cells having a high take percentage on the transplantation of the stem cells, and/or to provide an agent for maintaining the undifferentiated state of the stem cells. <；P>；SOLUTION: A cherry seed extract is used for the embryonic stem cells of a mammal, or somatic stem cells in a biomedical tissue including marrow, blood, fats, and skin tissue, or artificially produced stem cells to promote the proliferation of the cells in a state maintaining the undifferentiated state of the stem cells and additionally improve the take percentage of the stem cells to the biomedical tissue on the transplantation of the stem cells, thereby making useful for the regenerative treatment of the tissue. Therefore, the stem cells can largely contribute to the field of tissue regeneration, and the application to the fields of medical science, medicines, quasi-drugs, cosmetology, and health is expected. <；P>；COPYRIGHT: (C)2010,JPO&INPIT
