The Five Element Theory has a great deal to do with the practice of Chinese herbal medicine. Below is a picture of the five elements and how they affect one another. This picture comes from the Wikapedia Free Online Encyclopedia:

Each of the five elements represents organs of the body. Wood is representative of the liver; fire represents the heart; earth represents the spleen; metal represents the lungs; and water represents the kidneys.

The Five Elements and their functions is a diagnostic tool used by those who practice Chinese herbal medicine. Each element has a corresponding function to generate and, overcome and can be overcome by another element. Water, for example generates wood and overcomes fire but is overcome by earth while Wood generates fire and overcomes earth but is overcome by metal.

According to this theory: the kidneys (water) generate the liver (wood), overcomes the heart (fire) and is overcome by the spleen (earth). The Chinese herbalist uses this information to help him determine what herbs will make his patient feel better.

Since Chinese herbal medicine is based on the strength of Chi and the balance of Yin and Yang in the body, the object is to choose herbs that will strengthen Chi and restore the balance of Yin and Yang. The herb bai zhu (bulb) is used when there is a deficiency in the spleen (earth) and an excess in wetness (water), for example. Bai Zhu strengthens the spleen and dries wetness.

When Chinese herbalists use the terms "good and evil" they are not referring to morality but rather the ?good and evil' atmospheres that are perceived within the body of their patient. They are speaking of Yin and Yang as each relates to specific organs and thereby to the specific elements.