Similar to the theory of yin-yang, the theory of five elements: wood, fire, earth, metal, and water was an ancient philosophical concept used to explain the composition and phenomena of the physical universe. In traditional Chinese medicine the theory of five elements is used to interpret the relationship between the physiology and pathology of the human body and the natural environment.
In traditional Chinese medicine, the visceral organs, as well as other organs and tissues, have similar properties to the five elements.
The aspects involved in each of the five elements are as follows:
• Fire: draught, heat, flaring, ascendance, movement, etc.
• Wood: germination, extension, softness, harmony, flexibility, etc.
• Metal: strength, firmness, killing, cutting, cleaning up, etc.
• Earth: growing, changing, nourishing, producing, etc.
• Water: moisture, cold, descending, flowing, etc.
Between the five elements exist close relationships that can be classified as mutual promoting and mutual restraining. By mutually promoting and restraining functions of the various systems homeostasis is maintained. Overacting or over restraining can produce unbalances or pathological changes and health complications.