Library

In the *Tiao Jing Lun* (Treatise on Regulating the Channels) of the *Su Wen*, the Yellow Emperor asked: Why does Yin deficiency generate internal heat? Qibo answered: Due to excessive labor and fatigue, the physical form weakens and vital Qi declines, causing the Qi derived from food and grain to be insufficient. The Qi of the Upper Jiao fails to circulate, and the Lower Wan (lower stomach/duodenum) becomes obstructed. Stomach Qi stagnates and generates heat, which steams upward into the chest, thus producing internal heat. Pathogenic factors arise either from the Yin or from the Yang. Those arising from the Yang result from wind, rain, cold, and summer-heat; those arising from the Yin result from irregularities in diet and living habits, as well as emotional fluctuations such as joy and anger.

The *Tai Yin Yang Ming Lun* (Treatise on Tai Yin and Yang Ming) states: When one is attacked by treacherous winds and empty pathogens (external pathogenic factors), the Yang meridians receive them; when there are irregularities in diet and daily routine, the Yin meridians receive them. When received by the Yang, the pathogen enters the Six Fu Organs; when received by the Yin, it enters the Five Zang Organs. Entering the Six Fu Organs causes body fever, inability to lie down at proper times, and upward manifestations such as panting and calling out; entering the Five Zang Organs causes fullness and obstruction, with downward manifestations such as undigested diarrhea (Sun Xie), which may develop into intestinal dysentery (Chang Pi) over time.

The *Ju Tong Lun* (Treatise on Painful Conditions) states: Labor and fatigue lead to the consumption of Qi. During labor, one pants and sweats; both internal and external aspects leak outward, thus consuming Qi.

The *Bi Lun* (Treatise on Bi Syndrome) states: Yin Qi prefers stillness; in stillness, the Spirit is stored, but in agitation, it dissipates. If food intake doubles, the intestines and stomach are injured.

The *Ben Bing Lun* (Treatise on Root Diseases) states: Irregular diet and labor and fatigue injure the Spleen.

The syndrome of "labor and fatigue" refers to what Li Dongyuan called the "Internal Injury Syndrome." Any disease that arises internally rather than from external contraction is essentially an internal injury. However, Li Dongyuan specifically designated diseases caused by irregular diet and excessive labor as "internal injuries." Why is this? Both external contractions and internal injuries present with symptoms such as aversion to cold and fever. External cold-heat conditions refer to Cold Damage (Shang Han); internal cold-heat conditions refer to labor and fatigue. Cold Damage is due to excess external pathogens and is generally treated with dispersing methods; internal injury is due to deficiency of internal vitality and is generally treated with warming and tonifying methods. However, these two categories often present similar symptoms and are easily confused. Therefore, Li Dongyuan specifically used the term "internal injury" to distinguish it from external contraction, fearing that treating labor-induced injury as Cold Damage would inevitably lead to death. This is a major principle that must be clarified first.

First, regarding internal injury syndromes, Li Dongyuan focused on diet and labor. However, dietary injury has two types, and labor injury also has two types, which should be distinguished as follows:

First, regarding dietary internal injury: For those with irregular timing of meals, extreme hunger empties the "granaries" (stomach reserves) and inevitably injures Stomach Qi; extreme fullness exceeds digestive capacity and inevitably injures Spleen Qi. However, for illnesses caused by alternating periods of hunger and fullness, the injury stems primarily from hunger, so treatment should focus on regulating and tonifying, which aligns with Li Dongyuan's view. For cases not caused by hunger or fullness but by indulging in rich foods leading to stagnation and indigestion, treatment should focus on resolving stagnation and promoting digestion, following the formulas discussed in the section on diet. Thus, the two types of dietary injury—one due to deficiency from hunger, the other due to excess from stagnation—must be distinguished in treatment.

Second, regarding labor internal injury: There are cases where sudden fever occurs due to exhaustion, accompanied by lethargy, desire to sleep, reluctance to speak, and a pulse that is slow, large, floating, or fine, without signs of external pathogens. This is what contemporary people call "Labor Fever," and it should be treated primarily with warming and tonifying. There are also cases where chronic accumulation of labor and irregular diet injures the Spleen and Kidney, making one susceptible to external pathogens. This results in symptoms such as fever, headache, tight pulse, and aversion to cold, resembling Cold Damage. This is a combination of internal injury and external contraction, known as "Labor-Induced Cold Invasion." If treated as true Cold Damage, the standard treatments for Cold Damage cannot be used because the root cause is already deficiency from labor. If denied as Cold Damage, patients may still exhibit severe symptoms like macules, mania, chest binding, and delirium, leading people to insist on the diagnosis of Cold Damage. As Li Dongyuan stated: "After the siege of Daliang, many died; were they all infected by wind and cold?" This is profound truth. The suffering caused by war is obvious, while that caused by fame and profit is hidden. Thus, modern cases of labor-induced Cold Damage-like illnesses are mostly of this nature. Ignorant practitioners treat them recklessly, harming patients, asking if their natural lifespan had truly ended. This is truly pitiable. The two types of labor injury mentioned above are both internal injuries; one lacks external pathogens, the other includes them, and they must be distinguished and treated accordingly.

Third, irregular diet and excessive labor can all injure the body. Humans rely on diet for life, and diet relies on the Spleen and Stomach. Irregular eating injures Stomach Qi. Since the Spleen governs the four limbs, excessive labor injures Spleen Qi. The Spleen and Stomach are the foundation of health; once the foundation is damaged, illness is inevitable. People fail to exercise caution, and disease ensues. Some fall ill because labor stirs up deficient fire; others because hunger damages Middle Qi. Some suffer hunger after labor, or labor after enduring hunger. Among these, hunger is particularly damaging. Therefore, one should not face illness while hungry, exert oneself while hungry, expose oneself to cold while hungry, act impulsively while hungry, deplete essence while hungry, or engage in social obligations while hungry. Understanding these principles constitutes the way to prevent disease and preserve health. These violations are not limited to the poor and lowly; the wealthy and noble often commit them more frequently. Driven by circumstances, they exhaust their mind and strength, allowing pathogens to enter through deficiency. These are all signs of internal injury and deficiency. Unfortunately, contemporary physicians fail to discern this, labeling all conditions as Cold Damage regardless of deficiency or excess. They only know how to clear heat, expel pathogens, and use sweating, vomiting, and purgation methods. They ignore that the patient is already weakened by neglecting food and rest, and further attack with harsh treatments, depleting both root and branch. How can survival be expected? I have witnessed many harmed by this practice. I regret not being able to correct this immediately, but given the entrenched customs and difficulty in dispelling doubts, I have recorded Li Dongyuan's main ideas here as a lamp in the long night, urging readers to reflect deeply.