According to the theoretical understanding of aging, over time, the yin essence of the kidney and liver declines, and this leads to common signs of old age, such as drying of body fluids, fragility of body structures, graying of the hair, wrinkling of the skin, loosening of the teeth, and withering of the flesh. The basic text of Chinese medical theory, Neijing Suwen (ca. 100 A.D.), says that "One who is over 40 years of age will have his yin half-reduced." In ancient descriptions of trembling of hands and shaking of the head, and stiffening of the muscles, it is mentioned that these symptoms are a manifestation of wind and involve the liver organ system. The Neijing says: "All kinds of wind and dizziness are associated with the liver; all kinds of sudden stiffness are associated with wind." In order for the blood and yin of the liver to be full, the kidney essence must be adequate, as it is the source of the liver yin. The decline of kidney and liver functions have a common origin in the aging process in which kidney yin (or kidney essence) is reduced (1).

In order for the normal aging pattern to lead to Parkinson's-like symptoms, the liver yin has to become so weak that a syndrome of wind is elicited. This may occur because there are additional factors that adversely influence the kidney and liver. Genetic propensity to suffer from Parkinson's disease corresponds to inherited defects in the kidney essence. Susceptibility of the liver to deficiency and generation of wind may occur as the result of diseases that damage the liver, from excessive use of alcohol and drugs that can damage the liver, or from a long history of behaviors that are unhealthy. In addition, external wind may penetrate the channels and invade the liver to induce the internal wind syndrome. External wind is a mysterious concept invoking environmental factors of various types that adversely influence the body, starting at the body's surface and penetrating inward. The experience of external wind usually produces symptoms of aches and pains. The internal wind, whether generated from within or from the influence of external wind, produces symptoms of shaking, described in Compendium of Medicine this way: "The upgoing qi in the channels and collaterals does not keep its proper position, thus causing the head to shake and the limbs to tremble."

The mental disturbances that arise in some Parkinson's patients may be attributed, from the perspective of traditional Chinese anatomical connections, to a failure of the kidney to nourish the brain. In addition to genetic components contributing to this decline, there may also be weakening of the kidney by exposure to cold, by excessive fear, by excessive sexual activity, and by consuming foods, drugs, or other substances that harm the kidney and especially that deplete kidney yin. Also, physical injuries and surgeries can disrupt the normal interconnection of the internal organs and result in depletion of yin of the kidney and liver.

This interpretation of symptoms and signs associated with Parkinson's disease leads almost immediately to a therapeutic regimen: nourish the kidney and liver, with focus on nourishing yin, and sedate internal wind. While nourishing kidney and liver is often accomplished by herb therapy, calming wind syndromes is more frequently attempted through acupuncture therapy. In China, acupuncture and herbs have been used both independently and in combination.