1. Adopting the "three yang" portion of the Six Meridians differentiation

1. Adopting the "three yang" portion of the Six Meridians differentiation

The Six Meridians of cold damage encapsulate the eight categories of yin-yang, exterior-interior, cold-heat, and deficiency-excess, integrating principles, methods, formulas, and medicines into one comprehensive system. Its influence extends far beyond febrile diseases, becoming a model for syndrome differentiation and treatment across various conditions in traditional Chinese medicine. For over a thousand years, it has been praised by both Chinese and foreign medical practitioners. In terms of diagnosing and treating exogenous febrile diseases, the three yang differentiation accurately describes the onset and progression of febrile illnesses; the three yin differentiation discusses the management of sequelae after febrile diseases. In particular, the classification and treatment of the three yang syndromes are highly valued by clinicians, as they succinctly capture the characteristics of exterior cold with just a few phrases like "floating pulse, stiff neck and head, and aversion to cold"; they precisely depict the features of interior heat with "body heat, spontaneous sweating, no aversion to cold, but rather aversion to heat"; and the semi-exterior, semi-interior syndrome is primarily characterized by seven symptoms: bitter taste in the mouth, dry throat, dizziness, alternating chills and fever, chest and flank discomfort, reluctance to eat or drink, and irritability with nausea. These descriptions have been proven effective through the practice of generations of medical scholars, providing important guidance for the diagnosis and treatment of exogenous febrile diseases. Moreover, the Six Meridians of cold damage offer a wealth of clinically proven prescriptions. The 112 formulas recorded in "Shanghan Lun" form the foundation of traditional Chinese medicinal formula studies, with many later formulas derived from them, such as Guizhi Decoction, Xiaochaihu Decoction, and Baihu Decoction, each with numerous variations. According to personal experience, the Six Meridians of cold damage are particularly ingenious in regulating autonomic nervous system dysfunction—for example, "heartburn and bloating" can be treated with Xiexin Decoction; "after recovering from a serious illness, frequent salivation, lingering discomfort, and a feeling of cold in the chest" can be treated with Lizhong Decoction—both showing good clinical efficacy. In short, "Shanghan Lun" is an outstanding classic medical text, and the Six Meridians of cold damage is a diagnostic principle that guides clinical practice. Specifically for febrile diseases, the three yang syndromes accurately reflect the patterns of transmission and transformation of febrile illnesses. However, due to historical limitations, there are still some shortcomings in its application to the diagnosis and treatment of exogenous febrile diseases. For example, the three yin syndromes described in the Six Meridians lack logical connections among themselves, making it difficult to see the patterns of disease progression and transformation. Taiyin syndrome represents spleen-stomach deficiency-cold; Shaoyin syndrome represents heart-kidney deficiency-cold; and Jueyin syndrome is a mixed cold-heat syndrome. While these may indeed be complications or sequelae of febrile diseases, in most cases they appear in internal injuries and miscellaneous conditions, with little apparent connection to the progression of febrile diseases. Recently, Yan Derun stated: "In fact, the three yin syndromes do not transmit to each other, so they should not be treated the same as the three yang syndromes." "^⑤^ Shi Yiren also said: "My view is that the three yang syndromes represent cold-related illnesses and should be classified under the 'cold' section; the three yin syndromes represent changes in organ function and belong to the category of miscellaneous diseases, so they should be listed under the digestive, circulatory, and thoracic-abdominal sections." "^⑥^ Although Yan and others' views may not be entirely correct, their assertion that the three yin syndromes "do not transmit" is indeed thought-provoking. What exactly is the essence of the three yin syndromes? Commentators on "Shanghan Lun" often debate this issue without reaching a consensus. Only Lu Yuanlei has a unique insight: "Since the whole body is considered deficient-cold in Shaoyin, and the gastrointestinal tract is considered deficient-cold in Renyin, and there is no other type of deficiency-cold that could qualify as Jueyin, it must be a makeshift solution—a violation of the strict numerical order of the Six Meridians, akin to cutting off one's toes to fit the shoes." "^⑦^ Lu believes that Jueyin syndrome is a "centuries-old mystery" and strongly urges his colleagues not to cling rigidly to old conventions. According to "Shanghan Zabing Lun," which was compiled at the end of the Han Dynasty, the original text was scattered during wartime, and although Wang Shuhe later revised it, its original integrity remains impossible to verify. Generations of medical scholars, such as Fang Youzhi and Yu Jiayan, have expressed regret about this. Yu used the metaphor of "cutting up beautiful brocade and patching it with rags" ("Shanglun Pian") to describe the imperfections within its beauty. These earlier views have greatly inspired the author, who has therefore adopted the "three yang" portion of the Six Meridians in the "six-stage differentiation" for febrile diseases, designating the Sun as the first stage, Shaoyang as the second stage, and Yangming as the third stage, while omitting the three yin portions to use them for diagnosing internal injuries and miscellaneous conditions.