TCM, based on the theories of Yin–Yang, the Five Elements, Zang–Fu manifestation, etc., has always emphasized prevention. The Inner Canon of the Yellow Emperor emphasizes treatment before a disease arises. The Basic Questions states, “Hence the sages did not emphasize treating those who were already manifestly ill; they instructed those who had not yet developed tangible symptoms. Administering medicine mainly for already observable disease is comparable to digging a well after one becomes thirsty, or building weaponry after one is already engaged in battle. Would these actions not be too late?” .
To prevent disease, or to prevent further deterioration, TCM always reinforces healthy Qi, eliminates pathogens, and restores Yin–Yang balance. TCM considers individual characteristics, geographic locations, seasonal changes, and the Five Elements principles to predict further problems.
The nature of the disease and the pathological process have a close relationship with the constitutional characteristics of the patient’s body. According to basic TCM theories, clinical Constitution investigation makes a normal classification of quality into seven types: fairly balanced type, Yang deficiency, Yin deficiency, dampness–heat, wet phlegm, blood stasis, and Qi deficiency. Each type of patient except for the first one has inherent deviation or weakness in health. If we utilize the TCM strategy to change deviations, it will be the best way to prevent disease. Clinical effect of care must consider the intrinsic characteristics, age, gender, living conditions, physical factors such as regional differences, and so on.
According to the World Health Organization report, Conventional Western Medicine (CWM) cannot recognize “sub-healthy” patients (who suffer from some significant illness symptoms not picked up by CWM exam data); in some developing countries, about 70% of the urban population are in a sub-healthy state, because CWM does not recognize their disease soon enough. TCM’s differential diagnosis may catch the disease earlier by recognizing the symptoms or asymptomatic primary stage. TCM’s potential for catching the very earliest hint of disease is based on its attention to the intangible system (meridian, Qi, and syndromes). TCM emphasizes the symptoms and has the “Four Methods” diagnosis, including the practice of “visualization,” which sensitizes the practitioner’s ability to differentiate symptoms and find the health problem.
The diagnosis, etiology, pathology, and disease names of CWM differ from those of TCM, because CWM focuses on the disease process in the solid body. However, visceral symptoms are changeable manifestations of disease. It is TCM’s goal to diagnose the Qi stagnation, recognize intangible symptoms, and treat the pathology. So TCM prevents diseases by recognizing and treating the blockages in the intangible system which may or may not yet be causing the focus of disease in the solid body.