Huangdi’s Inquiry on Disease Causes and Climate in TCM

The Yellow Emperor asked Shao Yu, “I have heard that many diseases originate from wind, rain, cold, and heat. Malevolent energy infiltrates the body through the hair follicles and interstitial spaces. Some pathogens exit the body, while others linger within, manifesting as wind-induced swelling and sweating, consumptive fever, chills and fever, bi syndrome (arthritis), or accumulations. When climatic conditions are abnormal, the malevolent energy spreads and overflows in the body, causing innumerable symptoms. I hope to hear your explanation of these causes. As for those who fall ill simultaneously, some suffer from one disease, while others from another. I believe the natural climate affects people differently; otherwise, why would there be such diverse pathological changes?”

Shao Yu replied, “The malevolent energy of nature does not discriminate. Those who are exposed to it fall ill, while those who avoid it remain safe. It is not the energy that harms people, but people who invite the pathogenic influence upon themselves.”

The Yellow Emperor said, “Some people encounter malevolent energy at the same time and contract the same illness, yet their symptoms differ. I hope to hear your explanation.” Shao Yu responded, “This is an excellent question! Let me use the analogy of a carpenter cutting wood. A carpenter sharpens his axe to chop wood. Since the wood has different textures on its yin and yang sides—some parts are tough, while others are brittle—the axe struggles to penetrate the tough areas but easily cuts through the brittle ones, sometimes even notching the blade when encountering knots. Within the same type of wood, there are variations in toughness and brittleness; how much more so between different types of wood, with varying thicknesses of bark, amounts of sap, and inherent textures. Generally, trees that bloom early and sprout leaves first will lose their flowers and wilt their leaves when exposed to spring frost or strong winds. Prolonged scorching heat and drought will cause brittle, thin-barked trees to wither due to sap depletion. Persistent overcast and rainy weather will lead to thin-barked, sap-rich trees developing rotting bark and seeping fluids. Sudden violent storms will break the branches of rigid, brittle trees. Autumn frost accompanied by strong winds will cause such trees to have动摇根 and shed their leaves. These five scenarios each have distinct causes and degrees of damage; how much more so for humans?”

The Yellow Emperor asked, “How does the analogy of human and tree changes work?” Shao Yu answered, “When trees are injured, it is their branches that suffer. Branches that are rigid and sturdy remain unharmed. Similarly, humans are prone to illness because their joints, skin, and interstitial spaces are not robust, easily invaded and retained by malevolent energy, thus leading to illness.”

The Yellow Emperor said, “How should we observe those prone to wind-induced reversal of qi and profuse sweating?” Shao Yu replied, “Those with fragile muscles and loose interstitial spaces are easily invaded by wind pathogens.” The Yellow Emperor asked, “How can we discern fragile muscles?” Shao Yu answered, “In individuals where the muscles of the popliteal region (back of the knee) are not firm and lack distinct fibers, or even if fibers are present, they are coarse and sparse, and the skin is not dense, the interstitial spaces are loose.”

The Yellow Emperor said, “How should we observe those prone to consumptive fever?” Shao Yu replied, “Those with weak internal organs are susceptible to consumptive fever.” The Yellow Emperor asked, “How can we know if the internal organs are weak?” Shao Yu answered, “Individuals with weak organs often have a strong-willed temperament. A strong will leads to frequent anger, which easily damages the organs.” The Yellow Emperor asked, “How can we observe weak organs and a strong will?” Shao Yu answered, “Such people have thin, fragile skin, yet their eyes are deeply set and firm. Their eyebrows are upright, and their temperament is violent. A violent temperament leads to anger, which causes qi to reverse and accumulate in the chest. Blood and qi become obstructed and stagnate, filling the space between muscles and skin, preventing smooth blood flow and causing郁热 ( stagnant heat ). This heat consumes muscles and skin, resulting in consumptive fever. This refers to those with a violent temperament and fragile muscles.”

The Yellow Emperor said, “How should we observe those prone to chills and fever?” Shao Yu replied, “Those with fine bones and fragile muscles are susceptible to chills and fever.” The Yellow Emperor asked, “How can we observe the size of bones, the firmness of muscles, and differences in complexion?” Shao Yu answered, “The cheekbones are the key indicator of bone structure. Large cheekbones indicate a large skeletal frame, while small cheekbones indicate a small one. Thin skin and sunken muscles, weak and无力 (weak), with a dull and lifeless complexion on the chin that does not match the forehead, as if covered in grime, are characteristic. This is the method for diagnosing bones, muscles, and complexion. Additionally, thin arm muscles indicate insufficient bone marrow, making one prone to chills and fever.”

The Yellow Emperor said, “How should we observe those prone to bi syndrome (arthritis)?” Shao Yu replied, “Loose interstitial spaces and non-firm muscles make one susceptible to bi syndrome.” The Yellow Emperor asked, “Is there a fixed location for bi syndrome in the upper or lower body?” Shao Yu answered, “To determine the location of bi syndrome, one must observe the weakness in various parts of the body.”

The Yellow Emperor said, “How should we observe those prone to intestinal accumulations?” Shao Yu replied, “Thin, dry skin and non-firm, non-lustrous muscles indicate weak gastrointestinal function, allowing malevolent energy to linger and form accumulations, damaging the normal function of the spleen and stomach. Even minor malevolent energy can stagnate and form accumulations if the spleen and stomach are not properly regulated by cold and heat.”

The Yellow Emperor said, “I have understood the forms of diseases. Now, I wish to hear about the relationship between diseases and seasons.” Shao Yu answered, “First, determine the overall climate of the year, then grasp the climate of each season. When the climate is favorable to the disease, it improves; when unfavorable, it worsens. Even if a seasonal climate change is not severe, if it is incompatible with the body’s condition that year, it can still cause illness. This is due to the different physical constitutions leading to various diseases, which is the essence of the five transformations.”