According to modern medicine, AIDS is a kind of acute acquired immune deficiency syndrome. This happens to hold an identical view with"essential qi" in traditional Chinese medicine. "Qi" relies on vigour, and vigour is based on the scent and the essence of food. The transformation of the essential substance depends on the performance of zangfu functions. The functional actions of zangfu organs are the foundation of life. For the five zang orans, each has something to dominate and each performs its own functions. They are interdependent with each other and in harmonv with each other. Only when the five zang organs are in vigorous state and in harmony with each other, can the life-force of body be full of vital power and the body be full of "essential qi" . Amid the five zang organs, as long as the functions of liver, spleen and kidney remain in harmony, heart and lung will naturally be in the harmonious state, hence a healthy body and extended life expectancy can be achieved, That is the rule of "keeping relative balance of three internal systems" (or "three-dynamic balancing method" ).