Stem cells are fundamental units of every multicellular organism because they have the ability to differentiate into many kinds of mature cells. Stem cells have the characteristic of totipotency and also self-renewal. Adult stem cells possess multipotency with differential plasticity, which can be exploited for future generations of therapeutic options, though very early embryonic stem cells show totipotency. Fortunately, scientists did discover regulators in terms of pleuripotency, such as the oct-4 & Nanong protein. Stem cells occur in all of us, ranging from the initial stages of human development to the terminal stage of life. Stem cells are not specialized cells that become specialized cells, which comprise the various types of tissue in the human body. The ability of stem cells to regenerate and repair tissue is very promising. Stem cell therapy is a unique medical treatment that can use donor (allogeneic) or the body's own cells (autologous) to repair and regenerate damaged tissues. It has only been now that scientists have known stem cells well enough to consider the prospects of culturing them outside the body for extended periods.