Kidney yīn and kidney yáng

The two opposing, yet complementary aspects of kidney essential qì. Kidney yīn and kidney yáng are interdependent and mutually counterbalancing. Imbalance between the two is fundamentally attributable to insufficiency of kidney essential qì. When kidney yīn or yáng vacuity reaches a certain point, it may affect its complement so that the condition becomes one of dual vacuity of kidney yīn and yáng (detriment of yīn or yáng affecting its complement).

Kidney yīn has a moistening and nourishing effect on all the organs of the body, and when it is vacuous, general signs such as interior heat, dizziness, tinnitus, limpness of the knees and lower back, seminal emission, red tongue, and dry mouth are likely to appear. Owing to the loss of the nourishing effect of the kidney yīn, a whole variety of diseases, such as noninteraction of the heart and kidney, ascendant liver yáng, liver wind stirring internally, or heart fire flaming upward may develop. If the lung is affected, such signs as dry cough, tidal heat, upbearing fire, and dry pharynx are observed.

Kidney yáng warms and activates the other organs. Insufficiency of kidney yáng may therefore lead to disturbances of water metabolism and the reproductive functionand may also diminish the activity of the other organs. If kidney yáng fails to perform its activating function, signs of heart-kidney yáng vacuity such as heart palpitation, a slow pulse, sweating, shortness of breath, and cold of the limbs may be observed. Impaired absorption of qì by the kidney affects the lung, provoking rapid breathing at the slightest exertion. If the spleen is deprived of the warming action of kidney yáng, there may be early morning diarrhea or nontransformation of grain and water.

Conversely, yīn or yáng vacuity in other organs may affect kidney yīn or yáng. For example, liver yīn vacuity, ascendant hyperactivity of liver yáng, heart yīn vacuity, or effulgent heart fire may eventually sap kidney yīn, creating kidney yīn vacuity. Often, lung yīn vacuity also affects kidney yīn, and diarrhea caused by spleen yáng vacuity may eventually affect kidney yáng, this condition being known as spleen-kidney yáng vacuity.

Since kidney yīn and kidney yáng are the root of the yīn and yáng of all the organs of the body, they may also be referred to as true yīn or original yīn, and true yáng or original yáng.