“Shanghan Lun(Note),” “Essentials from the Golden Chamber,” “Pulse Diagnosis,” “Pulse Differentiation,” and “What Can and Cannot Be Done” were written by Zhang Zhongjing of the Han Dynasty. These five works are collectively known as “Shanghan ,” with “Shanghan Lun” being the most important because it contains all the fundamental theories of “Shanghan.” This book was written to explain “ShangHan.”. Because the content is primarily medical theory and contains few clinical cases, it is titled “Theoretical Medicine.”

Note:”Shanghan Lun ” is also translated as “Treatise on ShangHan” or “Treatise on Cold Damage.”

“Shanghan Lun uses a systemic functional perspective to demonstrate pathological phenomena, and its dialectical methods differ from traditional Chinese medicine; therefore, its content cannot be explained using traditional Chinese medicine theories. Since the publication of “Shanghan Lun”, no one has truly understood its theoretical system, leading to stagnation in the development of traditional Chinese medicine theory and a lack of progress. Because modern Chinese medicine theory is relatively abstract and lacks strong logic, many people consider Chinese medicine theory as unscientific.

The “Shanghan Lun” (Treatise on ShangHan) is characterized by its solid and profound theoretical foundation, advanced medical thought, rigorous logical thinking, close integration with clinical medicine, and profound understanding of the nature of diseases. It can be said that the “Shanghan Lun” is the only breakthrough point for achieving the scientification of Traditional Chinese Medicine; therefore, research on the “Shanghan Lun” must be elevated to a new level to achieve this goal.

This book, based on modern mathematical logic and physic, uses modeling methods to establish a systematic theory of physiology, pathology, pulse diagnosis, and pharmacology from the “Shanghan Lun” itself. Only in this way can we deeply understand the symptoms, pulse patterns, and related treatments described in the “Shanghan Lun.”

The following introduces some basic theories of the “Shanghan Lun”, aiming to give readers a basic understanding of its theoretical system.

The functional systems in the ShangHan include the disease-fighting system，the circulatory system,and auto-reaction system. When a patient is infected with an epidemic disease, the pathogen releases toxins that damage the body’s organs and tissues, resulting in a large amount of pathogenic substances. Once these pathogenic substances are released into the circulatory system, their levels rise. The auto-reaction system regulates these levels through the disease-fighting system.

The circulatory system in “ShangHan” encompasses the water, ‘jin fluid’ (the fluid in the circulatory system including lymph and white cell, but excluding blood and plasma), and nutrient blood systems. The body must transport and expel pathogenic accumulation through the circulatory system. Because the body’s disease-fighting process consumes significant amounts of water, jin fluid and nutrient blood, the circulatory system becomes overloaded and weakened. This reduces the supply of water, jin fluid, and nutrient blood to the disease-fighting system, impairing its ability to transport and expel pathogenic substances. Therefore, “ShangHan” believes that treating disease requires prior integration and strengthening of the circulatory system.

Since the flow rate and volume of body fluids, jin fluids, and blood nutrient are crucial to the disease-fighting system’s ability to transport and expel pathogenic factors, “Shanghan” places great emphasis on controlling these flow rates and volumes. Therefore, the prescriptions used to integrate and strengthen the circulatory system are formulated and administered in a manner consistent with the principles of fluid dynamics.

Because the degree of overload in the water, jin fluid, and nutrient blood circulatory system fluctuates, the level of pathogenic accumulation fluctuates, and the strength and weakness of the system vary, the patient’s symptoms and pulse condition undergo dynamic changes. Compared to chronic diseases, Therefore doctors must constantly observe the patient’s pulse and symptoms, and treat the patient with different prescriptions according to the patient’s pathological state at different times. It is unrealistic to try to treat infectious diseases with one drug or one prescription.

The body uses programmed information to control the influx and elimination of pathogens in its disease-fighting system. There are two types of disease-fighting programs: special programs and general programs. If the pathogen is highly toxic, destructive, and has a high accumulation rate (such as the influenza virus), the auto-reaction system will activate the special accumulation-control program. This aims to strengthen the influx and elimination of pathogens in the disease-fighting system, preventing accumulation from clogging organs, tissues, and the circulatory system, potentially disrupting the disease-fighting system.

If the pathogen is milder (such as the common cold), with less destructive power to organs and tissues, and a relatively low accumulation rate, the auto-reaction system only needs to execute the general accumulation-control program and avoids the more powerful special programs. These programs place a heavy workload on the circulatory system, potentially overloading and weakening it.

The disease-fighting program is executed in six-day cycles, and the body generally only needs to complete one cycle. This is why most patients recover within a week. If the accumulation of pathogenic factors is high and the disease-fighting system is insufficient, the body may need to undergo multiple stages of disease-fighting program.
During the special programs stage, the body’s resistance is strong, and the patient’s symptoms of chills, fever, and headaches are very severe, as these are manifestations of disease resistance. During the general  programs stage, the body’s resistance is relatively weak, and the patient’s symptoms are mild. Elderly or frail patients have a weak immune system and are unable to execute the disease-fighting program, so they do not experience the associated symptoms.

The fluid substances that are distributed throughout the body and participate in systemic functions are called “yin fluids.” Yin fluids include water, jin fluids, and nutrient blood. “Qi and fluids” are the collective term for “yang qi” and “yin fluids”. The function of “yang qi” is to regulate the supply of “yin fluids”. “Essence Qi” are the refined substances produced after food digestion. The body uses these “Essence Qi” to transform into “Qi and Fluid”.

ShangHan suggests that the body has a reserve system that stores “Essence Qi”. When the “Qi and Fluid” supply to the disease-fighting system is insufficient, “Essence Qi” are released from this reserve system, thereby enhancing the body’s ability to generate “Qi and Fluid”. Pathological conditions in which the body relies on this reserve system are called “Yin diseases,” while those that do not are called “Yang diseases.” If the disease-fighting system’s demand for reserve “Essence Qi” is excessive, causing the reserve system to become severely overloaded, the patient will experience extreme fatigue, a warning sign from the body that cannot be alleviated by sleep.

In the context of chronic diseases, this pathological condition is what modern medicine calls chronic fatigue syndrome. In the context of infectious diseases, the Treatise on ShangHan calls this pathological condition “Shaoyin disease.” Due to the high rate of accumulation of pathogenic factors, the body consumes a large amount of pathogenic “Qi and fluids” during the process of transporting and expelling these factors.
When a patient develops Shaoyin disease, the demand for their reserve vital energy is extremely high. This severely overloads the reserve vital energy supply system, rapidly weakening it. This leads to a decrease in the “Qi and fluid” supply to the disease-fighting system, resulting in a loss of the body’s ability to fight disease. Therefore, “Shaoyin disease” is the primary cause of death.

The “ShangHan Lun” considers relapsing fever a yin disease. When a patient develops relapsing fever, fever and chills alternate, typically lasting four to six days. During each period, the patient experiences different pathological conditions, each with its own corresponding treatment.

The medical philosophy of the “ShangHan Lun” was advanced, its theoretical system complete and rigorous, and its understanding of the nature of disease surpasses that of modern medicine.