With the development of modern medicine, an increasing awareness has developed regarding the limitations of a specialized and compartmentalized approach to clinical practice that largely ignores the interconnectedness of the mind, body, and spirit. Although contemporary medicine now accepts this interconnectedness, practitioners tend to think that the emotions play a secondary or excitatory role in producing disease rather than being a primary causative factor. Traditional Chinese medicine (TCM), which stems from Confucianism, Buddhism, and Daoism, views the body and the spirit as inseparable. This construct provides the foundation for the whole system of TCM, and therefore constitutes the backbone of TCM. This article presents the ways in which emotion can act as an internal etiological factor that produces a pathogenic mechanism and that underlies various psychosomatic diseases. Therefore, this article intends to integrate the ancient classic treatise established in the Yellow Emperor's Canon of Internal Medicine with current data. Likewise, the authors discuss their empirical experience to illustrate the following concepts: (1) the factors contributing to emotional impairment; (2) the holistic approach to diagnosing psychosomatic disease; (3) the integrative therapy necessary to restore the balance of body and mind; and (4) the role of emotional theory in nursing care and the prevention of psychosomatic disease.