What is meant by Qi? The concept of Qi is based on the ancient Chinese initial understanding of natural phenomena. That is, Qi is the most basic substance of which the world is comprised. Everything in the universe results from the movements and changes of Qi. This concept was introduced into TCM and became one of its characteristics. After a comprehensive survey of the statements on Qi in TCM documents, we have come to the

conclusion that the meaning of Qi in TCM has two aspects. One refers to the vital substances comprising the human body and maintaining its life activities, such as the Qi of water and food (food essence), the Qi of breathing (breathing nutrients) and so on. The other refers to the physiological functions of viscera and bowels, channels and collaterals, such as the Qi of the heart, the lung, the spleen and the stomach and so on. The Qi here referred to, is specifically the physiological functions of these viscera and bowels.