Yin and yang refer to qi, blood, body fluids and visceral essence in the human body. Normal physiological activities depend on the balance between yin and yang. The excess or deficiency of yin or yang will inevitably lead to dysfunction of certain organs and cause disease. The basic principle of acupuncture and moxibustion therapy is to regulate yin and yang and restore their coordination. That is also the therapeutic effect of acupuncture and moxibustion therapy. There are several conditions of im-balance of yin and Fang. Preponderance of yin and Fang, decline of yin and yang, and asthenia of both yin and Fang are the basic manifestations in the disorder of yin and yang. So different therapeutic methods are used in the treatment of such pathological changes with acupuncture and moxibustion therapy. For example, heat syndrome due to Fang predomination should be treated by reducing Fang-heat while cold syndrome caused by yin predomina-tion should be treated by warming and dispersing yin-cold. Asthenia-cold syndrome due to failure of yang astehnia to control yin should be treated by strengthening Fang while asthenia-heat syndrome due to yin asthenia and Fang sthenia should be treated by reinforcing yin. Asthenia of both yin and Fang should be treated by reinforcing both Fin and Fang.
