See Article History Alternative Title: TCM Traditional Chinese medicine TCM , system of medicine at least 23 centuries old that aims to prevent or heal disease by maintaining or restoring yinyang balance. That opus provided the theoretical concepts for TCM that remain the basis of its practice today. In essence, traditional Chinese healers seek to restore a dynamic balance between two complementary forces, yin passive and yang active , which pervade the human body as they do the universe as a whole. According to TCM, a person is healthy when harmony exists between these two forces; illness, on the other hand, results from a breakdown in the equilibrium of yin and yang. The hundreds of cabinet drawers, glass cases, and jars in a typical pharmacy hold an enormous variety of desiccated plant and animal material.