Embryonic stem cell is the promising novel therapeutic tool for various degenerative diseases and tissue injuries. With the concept of cell and tissue therapy, many chronic disorders will be curable. The present article provides basic knowledge of stem cell in areas of definition, classification and future clinical applications. In addition, stem cell application is not only focusing on regenerative purpose, but also concentrating on more understanding about the early human development and the pathophysiology of genetic diseases at the cellular level. However, there are some technical problems and ethical concern that should be resolved before applying stem cells into clinical practice.

Keywords: Introduction, Stem cell medicine, Regenerative medicine, Adult stem cell, Embryonic stem cell