In the human body, major organs are paired according to yin and yang. Yang has to do with function and movement. Yin provides the structure. Thus, the six fu (hollow) organs, responsible for moving and transforming substances, are considered yang. The five zang (solid) organs, used for collecting and storing, are classified as yin. Qi is yang; blood is yin. The physical body is yang and the soul is yin. The causes of human disease, according to the theory of yin and yang is as follow:
- Yang (external) causes
- Acute physical traumas such as cuts, burns and fractures involve some form of localized damage. The causes are evident and are clearly not the result of a yin disturbance. Western medicine is therefore the most effective treatment for this type of injury. Common sense tells us that if our artery is cut, we would want to stop the bleeding immediately with emergency medical intervention.
- Organic factors, such as viruses or bacteria also fall under the category of yang causes of illness, because they are external pathogens that disturb yang functions. Modem medicine would also be the recommended treatment for these types of disease, especially in epidemic situations.
- Yin (internal) causes
- Emotional factors, such as sadness and depression can disturb the yin aspects of a person and bring about disease. According to Western medicine, these kinds of illnesses would be considered psychosomatic.
- Prolonged bouts of depression and other types of intense emotion can make one more susceptible to illness. Stress and even the fear of illness itself may lead to diseases. This kind of phenomenon is referred to as a yin disturbance. Diseases brought on by yin causes can be complicated and modern medicine has not proven to be consistently effective in treating them. Thus, Traditional Chinese medicine using yin yang and the Five Elements concepts (e.g acupuncture) have a place here.
- Transformation of Yin to Yang and Yang to Yin Disease
- The Yin/Yang theory also states that everything is constantly changing. This includes diseases. A disease can change for the better or for the worse and can transform from a yin condition to yang condition or vice versa. An example of this transformation is the change from a long-term condition of high blood pressure, which was originally caused by yin factors, to cerebral hemorrhaging or heart attack, which are acute or yang diseases.