The Three Categories of Causes of Disease (Shan-Yin)

pathology / etiology

The “San-Yin” classification divides the causes of disease into three groups. External causes are the six climatic pathogens (wind, cold, heat, dampness, dryness, and fire) that invade from the outside. Internal causes are the seven emotions, which damage the organs from within. “Neither external nor internal” refers to other factors: poor diet, overwork and excessive rest, injuries, bites, parasites, and irregular sexual activity. This framework links lifestyle and environment to the development of disease and forms the basis of prevention.