The Application of the Five Elements Theory to Medicine
Applied to Chinese medicine, the interrelationships of the five elements further explain the correlation between the various parts of the human body as well as the correlation between the human body and the natural environment. They are particularly useful for explaining the pathogenesis of complicated physiological and pathological conditions. Following are some examples:
Water nourishes wood. This figuratively denotes that a sound Liver needs adequate nourishment of Kidney yin. If Kidney yin is insufficient, usually there is a deficiency of Liver yin accompanied by exuberant Liver yang, manifested by dizziness, tinnitus and blurred vision. In the latter case, the pathogenesis is attributed to "failure of water to nourish wood," and the treatment is "replenishing water to nourish wood," i.e., replenishing Kidney yin as the major therapeutic measure.
Wood acts on earth. This explains the physiological relationship between the Liver (wood) and the Spleen and Stomach (earth). However, if the Liver is diseased (e.g., depressed or stagnated), it may act on the Spleen and Stomach excessively, causing dysfunction of the latter. This is called the "overriding by wood of earth."
Earth promotes metal. Physiologically the Spleen (earth) transforms the nutrients from food and transports them to the Lungs (metal). This rule can also be used in the treatment of a chronic consumptive disease of the Lungs. In treating such a disease, reinforcement of the Spleen usually plays an important role. This is called "reinforcing earth to strengthen metal."
So far as the "mother-child" relationship is concerned, if the Liver is the "mother" organ, then the Heart is the "child" organ. Deficiency of Heart blood may involve the Liver, causing blood deficiency of both the Heart and Liver. Hyperactivity of the Heart may induce hyperactivity of the Liver, resulting in hyperactivity of both the Heart and Liver. Both of the above examples illustrate the conditions expressed as "a diseased child organ implicates its mother organ."
Closely related to the "mother-child" relationship is the following principle of treatment, which is particularly useful in acupuncture therapy. "Reinforce the 'mother' in deficiency conditions, and reduce the 'child' in excess conditions." This principle is based on the inter-promoting relationship among the five elements. During acupuncture, if the syndrome is deficient in nature, points of the mother meridian are usually selected for reinforcement. For example, in a patient with deficiency of Liver yin, reinforcing manipulation at Yingu (KI 10) is often applied, because Yingu is the sea point of the Kidney Meridian. If the syndrome is excess in nature, points of the child meridian are usually selected for reduction. For example, in a patient with exuberant Liver fire, reducing manipulation at Shaofu (HT 8) is often helpful, because Shaofu is the spring point of the Heart Meridian. Of course, in both examples, the points of the Liver Meridian itself can also be selected.
As Chinese medicine developed and became more sophisticated, the original rules and sequences of interrelationships among the five elements were felt to be no longer adequate to explain all the physiological and pathological changes. Therefore, some modifications were made to the five elements theory. For instance, the descending actions of the Lungs (to send down essence and qi, to control the passage of water, etc.) are helpful to the Kidneys, but the latter also assist the Lungs in inspiration. (Insufficiency of the Kidney function may lead to dyspnea characterized by shortened inspiration and prolonged expiration.) According to the five elements theory, we just say "metal promotes water," but clinically we usually say "metal and water promote each other."
Another problem is terminology. Water and fire are two of the five elements, but they are also used in etiology as pathogenic factors, and in diagnosis as names of syndromes. Particularly, the word "fire" is very misleading. Even in physiological conditions, fire, i.e., heat energy necessary for all life activities, particularly for the function of Spleen in digestion, absorption and assimilation, is produced by the Kidneys. It is called "vital fire," an equivalent to "Kidney yang." Although fire (Heart) promotes earth (Spleen) through blood circulation, but by saying "fire promotes earth," we usually mean that the vital fire warms up the digestive function of the Spleen. In chronic diarrhea accompanied by edema and intolerance of cold, the diagnosis is "fire fails to promote earth," and the treatment is "reinforce fire to promote earth." In these statements the word "fire" refers to vital fire, i.e., Kidney yang. In some other instances, however, fire still denotes the Heart. "Coordination of water and fire" explains the physiological interrelationship between the Kidneys and the Heart. If Kidney yin (water) is insufficient to check the activity of the Heart (fire), there may occur "incoordination of water and fire," marked by restlessness and insomnia.
The confusion in terminology originated in the convoluted course of development of Chinese medicine. The theory of the five elements was formed thousands of years ago, and its application to medicine was first recorded in The Medical Classic of the Yellow Emperor, a product of the Warring States Period. The theory of vital fire was proposed by leading physicians in the 16th century. Since then, the Kidneys have been taken as the "organ of water and fire," in which "water" refers to its yin aspect, and "fire" to its yang aspect. This doctrine concerns yin, yang, water and fire within one internal organ; though related to the five elements theory, it cannot be placed on a par with the latter.
Therefore, there have been controversies concerning the validity of the five elements theory. The main objection is to the classification into five categories. For example, the ordinary divisions of the year according to the weather in the temperate zone are the four seasons (spring, summer, autumn and winter) and in the tropical zone only two seasons (dry and rainy). The reason for adding late summer in order to make up the number of seasons to five is far-fetched. However, the quintessence of this theory is not that the number of five should be held sacrosanct, but that the mutual regulatory relationship between different types of matter should be recognized. The inter-promoting (producing) and inter-acting (checking) relationships among different systems or organs, to a great extent, are comparable with the theory of feedback control in Western medicine, but their application to the explanation of physiological phenomena and pathological changes has a much broader spectrum than the feedback mechanism. They can be taken as the basic rules of self-regulation of the human body at various levels. In fact, in modern physiology the significance of feedback control is no longer limited to research into neuro-humoral regulation, it has also been applied to research into immunology, molecular biology, genetic information and gene regulation. In a word, the five elements theory can be regarded as a general rule of correlation and coordination among the various parts of the human body and their functions, though the detailed description may not be precise.
The Application of the Five Elements Theory to Medicine