Yin and yang represent two opposite yet complementary aspects of objects. Because the relationship between yin and yang is always opposite, interdependent and interactive, it keeps them operating in a dynamic balance. The ancient Chinese incorporated the yin-yang concept into medical practice by using it as a tool for comparative analysis and for understanding the body’s structure, physiological changes and pathological developments. Based on yin-yang and the five-elements concepts, guidelines for clinical diagnosis and treatment were formulated. The body can be divided into the upper (yang) and the lower (yin); the back (yang) and the abdomen (yin); the surface (yang) and the interior (yin); the hollow organs such as the stomach, bladder, gall bladder and intestines (yang) and the solid organs such as the heart, liver, spleen, lungs and kidneys (yin). Each organ can be further divided into yin characteristics related to nourishment functions, and yang characteristics related to heat and stimulation functions. In texts for a particular organ, this might be expressed as heart yin versus heart yang and kidney yin versus kidney yang. These classifications help traditional Chinese medicine (TCM) practitioners understand general properties of complicated structures. TCM views human life as a physiological process in constant motion and change, which are nothing more than opposition, interdependence, interaction and mutual transformation among the functional and physical forms. Physical forms are yin; functional properties are yang. Both the physical form and function are dynamically balanced. Maintaining this balance is the way TCM believes bodily health is achieved. When the equilibrium is broken, disease occurs. There are many ways in which the body becomes unbalanced. Some typical TCM descriptions of this are “yin deficiency’, “yang excess”, “hyperactivity of heat”, “too much cold” or “vacuity in the exterior”, which is a morbid condition whereby a person becomes susceptible to an invasion of pathogens in the superficial regions of the body. The term “excess in the exterior” may also be used. This is a condition resulting from an invasion of pathogens in the superficial portion of the body when the so-called protective energy isn’t yet weakened and the superficial regions remain intact. Since disharmony of yin-yang is the root cause for most disease development, it’s essential to reduce the source of imbalance. Some symptoms attributed to an excess yang state include a lustrous complexion, heavy breathing and a rapid pulse. Excess yin symptoms might include a pale complexion, feeble breathing and a slow pulse. This sets a guideline for general diagnosis. Herbs are prescribed to match their therapeutic nature with a syndrome, namely, to remove excesses or replenish deficiencies. In application, people with pneumonia may have a high fever, red face, coarse respiration and a rapid and forceful pulse. These pathological signs are considered to show excess of “heat”, which means the body is in a predominantly yang state, or has “excess yang”. In this case, the strategy would be to cool down or eliminate the “excessive heat” with “cold” herbs. Cold herbs aren’t physically cool to touch, but possess cooling properties. Examples of cold herbs are gypsum and wind-weed rhizome. Once the heat is removed, yin-yang balance is restored and the pneumonia resolved. The herbs used wouldn’t be specific for the lungs, but also resuming harmony in the whole body. A decoction of herbs can trigger actions on a systemic level to promote healing. Exactly how TCM remedies work is a challenge modern science is striving to understand better. Rose Tse and Angela Collingwood are editors for Shen-Nong, a subsidiary of Integrated Chinese Medicine. Before taking any medicine. Consult your TCM or general practitioner. Rose Tse and Angela Collingwood info@shen-nong.com Edited by Suzanne Harrison suzanne.harrison@scmp.com Published: March 27, 2005 Source: South China Morning Post