What is 'health' and 'disease'?

Any system of medicine must answer the questions 'What is Health' and 'What is disease'? Traditional Chinese medicine holds that health exists when yin and yang within the human body and between the human body and the external environment are kept in a normal, dynamic balance. If the balance is impaired, disease will result. Therefore, an imbalance of yin-yang is always considered the general pathogenesis of disease. Pathogenic factors impair the normal yin-yang balance. They may originate in the external environment or within the human body. In any disease pathogenic factors attack the body, while on the other hand the vital energy resists them. Disease is the struggle of the vital energy against the pathogenic factors. Many statements in the Canon of Medicine relate to the battle between the vital energy and the pathogenic factors, emphasising the resisting capacity of the former against the latter: " Where there is abundant vital energy in the body, invasion of the pathogenic factors is impossible." "When the pathogenic factor enters the body, vital energy is bound to be insufficient." "A pathogenic factor, such as wind, rain, cold or heat, itself is unable to cause damage to the human body unless there is insufficiency of the vital energy. Some people with good resistance, though caught in a heavy rain and strong wind, do not get ill. Therefore, merely the pathogenic factor itself is not enough to cause a disease." The limitations of natural science and technology during ancient times prevented traditional Chinese medicine practitioners from discovering pathogens, such as bacteria and viruses. Practitioners did discover etiological factors by observing and analysing clinical manifestations. Though not entirely logical from the modern point of view, this etiology is very useful in clinical practice since it is closely related to therapeutic effects. Pathogenic factors are usually classified into two groups: the exogenous, which cause exogenous diseases of external infections, and the endogenous, which cause endogenous diseases or internal diseases. Exogenous pathogenic factors include abnormal atmospheric changes, pestilential pathogens, trauma, etc. Common endogenous pathogenic factors are emotions (such as joy, anger, melancholy, anxiety, grief, fear, fright), improper diet, over fatigue, overindulgence in sex, etc. Among exogenous pathogenic factors, abnormal atmospheric changes are most significant. Not only do they cause seasonal diseases, such as colds in winter and heat-stroke in summer, they also cause most infectious diseases marked by epidemicity. There are six kinds of atmospheric changes: wind, cold, summer-heat, damp, dryness and fire (intense heat). In a narrow sense, these factors are closely related to changes out of season, such as a warm spell in winter or a cold snap in summer, it can become pathogenic because the body is unable to adapt to these changes. Of course, there is no clear-cut line between normal and abnormal or non-pathogenic and pathogenic. A sudden violent change may not harm individuals with a strong constitution, while those with a weak constitution may find even a mild change pathogenic. Therefore, a practitioner cannot determine the cause of a disease merely by observing atmospheric changes.

Traditional Chinese Medicine Body System

Traditional Chinese Medicine, Shaped by philosophy and restricted by the historical conditions of the natural sciences, it is quite different from modern Western medicine in its conception of the structure of the human body. One of the most outstanding features of this conception is that of the human body as an integral whole. All component parts, including organs and tissues, are considered with respect to the whole body and to their close relationships. Its noteworthy that during its long history of development, traditional Chinese medicine has undergone great improvements, yet little modification in the conception of the structure of the human body has occurred. In fact, most of the traditional theories and principles are founded not upon anatomy but rather upon functional activities, either physiological of pathophysiological, and rely particularly heavily upon the notion of therapeutic effects. It should also be noted that all the traditional physiological and pathophysiological knowledge was not obtained by laboratory experimentation on isolated organs and systems but rather through the clinical observations of practitioners who viewed the human body as an organic whole. In traditional Chinese medicine internal organs are the core structure of the functions of the human body. An internal organ in traditional Chinese medicine, also called zang-fu according transliteration, refers to a comprehensive system of physiological functions rather than an anatomical entity. There are five zang organs: heart, liver, spleen, lungs, kidneys. There are six fu organs: small intestine, gall bladder, stomach, large intestine, urinary bladder and sanjiao (triple energiser)* Generally speaking, zang organs are solid visceral organs, while fu organs are hollow, serving chiefly as passages for food water and waste. Physiologically, structural and functional connections exist among both the zang and fu organs. Each zang organ is particularly associated with a fu organ. They share functions and are connected by meridians, i.e., the heart and the small intestine, the liver and the gallbladder, the spleen and the stomach, the lungs and the large intestine and the kidneys and the urinary bladder. Sanjiao (triple energiser)* actually refers to the body cavities: the upper-jiao or upper energiser is the thoracic cavity in which the heart and lungs are situated; the middle-jiao or middle energiser is the upper abdominal cavity where the spleen and stomach lie; the lower-jiao or lower energiser is the rest of the abdominal cavity containing the liver, kidneys, intestines and bladder. In some instances, each part of sanjiao can be used as a comprehensive name for the organs it contains, e.g., middle-jiao can mean the spleen and stomach.