core concepts of traditional Chinese medicine

Core concepts of traditional Chinese medicine

The human body’s “jin” (fluids) and “ye” (liquids) differ not just in their consistency—whether thin or viscous—but more importantly in their origins. “Jin” emerges from the skin’s interstices, such as sweat that flows freely; even when lost, it is relatively easy to replenish through diet. In contrast, “ye”—like tears, saliva, semen, vaginal mucus, gastrointestinal mucus, and bile—originates from the body’s “essence” (jing). Once depleted, it is difficult to restore. Simply drinking water won’t resolve the issue and may even worsen thirst.

For those with “solid cold” in the stomach qi, sensation becomes numb, and they may not care what they drink, yet their digestion suffers. For most people, excessive water intake relaxes the smooth muscles of the stomach and intestines, causing fluid retention and gurgling sounds as water flows through the bowels. In the small intestine, heat separates the water into “clear” and “turbid” components: the spleen absorbs the “clear” portion, transforming it into “jin,” which the lungs then distribute throughout the body; the “turbid” portion is sent to the large intestine and bladder for eventual excretion.

“Ye” does not come directly from food or drink but from the kidney essence stored within the body, existing as brain marrow, bone marrow, visceral fat, or subcutaneous fat. When needed, this essence is vaporized by primal qi in the lower dantian (energy center), becoming a viscous liquid. The triple burner (sanjiao) then circulates it throughout the body, nourishing cells, moistening tissues, and entering the blood vessels as blood. Thus, the distinction between “jin” and “ye” lies not only in texture but in their sources and formation.

Dryness in the body arises from three main causes:

1. Excessive Yang Qi: External pathogenic factors like heat or dryness, as described in the Huangdi Neijing’s Treatise on Heat, can invade: “On the first day of a cold injury, the Taiyang channel is affected, causing headaches and a stiff back. On the second day, the Yangming channel is involved, leading to fever, eye pain, nasal dryness, and sleeplessness.” The Yin-Yang Correspondence chapter adds: “Excess heat causes swelling; excess dryness causes desiccation.” High fever depletes “jin,” resulting in dryness. Internally, improper diet or emotional agitation (e.g., the “fire of the seven emotions”) can generate heat, consuming fluids, as noted in the Treatise on Flaccidity: “When spleen qi becomes hot, the stomach dries and thirst arises, leading to muscle numbness.”
2. Loss of Yin Containment: Excessive sweating or urination depletes “jin,” while diarrhea, vomiting, or frequent seminal emission and vaginal discharge harm “ye.” The lungs govern the skin and regulate opening and closing. External wind or misuse of sweat-inducing drugs can open the skin’s interstices, causing fluid loss and even damaging yin, blood, and essence. The Ling Shu states: “If blood is lost, there is no sweat; if sweat is lost, there is no blood.” The Treatise on Cold Damage warns: “Do not induce sweating in those with nosebleeds or blood loss.” Modern overuse of aspirin to prevent blood clots often leads to excessive sweating and even hair loss.
3. Deficient Yang Qi and Impaired Transformation: The small intestine relies on its fiery nature to separate clear from turbid, while the bladder vaporizes fluids to produce “jin.” If yang qi weakens, symptoms like dry mouth without desire to drink, or rinsing the mouth without swallowing, may appear. In severe cases, water is urinated out immediately, leaving thirst unrelieved or worsened. Formulas like Wu Ling San or Ling Gui Zhu Gan Tang from the Treatise on Cold Damage warm yang and promote water metabolism to address this. During thirst, hot water and warming herbs are preferable to gulping cold water, which can stagnate and burden the body.

Additionally, insufficient intake naturally reduces “jin.” Many believe cold water quenches thirst, but hot water eases the digestive load, aiding transformation into bodily fluids. Drinking should be slow—small sips, as the Chinese character “pin” (to taste) suggests—allowing absorption. Ancient practices, like adding tea to plain water or salt to watermelon, prevent fluid loss. Fruits and vegetables, with their balanced acidity and trace elements, are ideal for replenishment.

Those deficient in yin fluids need dietary and medicinal support to restore essence, such as pork skin broth, bone marrow soup, or the Da Bu Yin decoction (pig spinal marrow with huangbai and zhimu). Thirst can also stem from heart fire, unrelated to dryness but tied to emotional unrest. Anxiety or agitation often causes a dry mouth and throat—occasional instances are normal, but frequent occurrences signal illness. Ancient methods like swallowing saliva or massaging the Yongquan acupoint on the kidney meridian can nourish kidney water, calm heart fire, and relieve emotional thirst.