For the traditional Chinese medicine, we are alive and healthy because the human body is kept in a state of harmony. This state is a balance between the yin and yang, between the various organs of our body and between it and the environment in which we live. Constantly, this harmony is disrupted by the daily activities and by the different influences of the external environment that influence in our bodies and in the performance of our bodies.

When a person is healthy any discrepancy is solved quickly, while maintaining the dynamic equilibrium. Thus, the agency retains the health and the psychological balance normal; When this dynamic equilibrium is altered and does not recover, we feel ailments and we are victims of diseases we recall that for the traditional Chinese medicine diseases are the factors that can alter (or decompose) the balance of the human body.

Since always, in China have tried to understand and explain these factors that can because diseases ranked in various categories. For the doctor Chen Yan, during the reign of the Song dynasty, this classification was as follows:

• External causes.
Comprise the climatic influences external producing diseases.

• Internal Causes.
Comprise the emotional disorders that affect the visceral organs, causing diseases.

• Causes no external or internal.
Include other factors that affect the health as diet, injuries and sexual activity.