The theory of five elements in acupuncture.

The theory of five elements is extensively used in traditional Chinese medicine. It is proposed that the theory of five elements was developed on the basis of the theory of elements, the law of contagion and the law of similarity which were prevalent in that era. The theory of elements spread in various forms all over the face of the globe. The law of contagion stated that objects, which at one time had been in continuity or juxtaposition, continued to exert an effect one upon the other. The internal organs were coupled probably on the basis of the law of contagion. The law of similarity stated that objects or circumstances which bear apparent similarity in form, shape, color or sequence of events, were considered to be fundamentally related. On the basis of the law of similarity the coupled internal organs were classified into five elements and the theory of five elements was compared with various things like seasons, color, tastes, emotions, etc. The theory of five elements is probably the earliest documented evidence correlating physiology with pathogenesis of diseases and a guideline for treatment of diseases.