Original qi, also known as primordial qi, is the source qi that serves as the driving force for the activities of zang-fu organs. Transformed from the prenatal essence and nourished by the postnatal essence, it is distributed throughout the body via triple energizer (sanjiao). It internally permeates five zang-organs and six fu-organs and externally reaches the skin, striae, and interstices, promoting and stimulating the physiological functions of all organs and meridians. Original qi performs two physiological functions. First, it promotes and regulates growth, development, and reproduction. When the reproductive essence from parents combines and develops into an embryo, original qi comes into being. Second, original qi propels and regulates the physiological activities of zang-fu organs, meridians, as well as other organs and tissues when it flows to every part of the human body via triple energizer (sanjiao).