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The syndrome of cough, in ordinary common colds, arises when wind pathogen attacks the skin and hair, internally combining with the Lung. The symptoms are merely nasal congestion and a heavy voice without fever. People often regard this as a mild form of wind injury and neglect it, paying no attention to it. However, the causes leading to cough already differ regarding cold/heat and interior/exterior. If there is fever accompanied by cough, the disease also undergoes transmission; one should not simply assume that cough is a lung disease and treat it exclusively from the perspective of the Lung meridian.

When the exterior syndrome of Taiyang disease is unresolved and combines with cold-fluid retention, thereby causing cough, the classic text states: "In cold damage, if the exterior is not resolved, there is water qi beneath the heart; for those with dry heaving, fever, and cough," Xiao Qing Long Tang (Minor Blue Dragon Decoction) is the primary treatment. This is because exterior and interior cold combine, which cannot be resolved without warming agents. The formula uses Mahuang (Ephedrae Herba) and Guizhi (Cinnamon Twig) to dispel exterior cold; Banxia (Pinelliae Rhizoma) and Ganjiang (Zingiberis Rhizoma) to dispel interior cold; assisted by Shaoyao (Paeoniae Radix Alba) and Wuweizi (Schisandrae Fructus) to restrain the rebellious Qi of the Lung. This is a purely warming formula. As for Lung distension, characterized by cough and rebellious Qi, irritability, wheezing, and a floating pulse, the same formula is used with Shigao (Gypsum Fibrosum) added. This is because the Lung Qi has become hot, while cold-fluid retention lingers within, overwhelming the Lung. Therefore, the acrid-warm nature of Mahuang and Guizhi is not abandoned, but Shigao is added to descend the Lung Metal's clear and descending Qi, guiding water downward. This employs the method of "treating heat with cold" (using cold herbs in a warm context or vice versa depending on interpretation, here referring to balancing heat with cold properties), and is no longer suitable for a purely warming approach. If Yangming heat is severe, with Fire overacting on Metal (Lung), causing cough due to heat, not only would the misuse of Mahuang and Guizhi lead to significant adverse transformations, but even the acrid-warm nature of Banxia is unsuitable. One should follow Zhang Zhongjing's method, replacing Banxia with Gualougen (Trichosanthis Radix), and to subdue Yangming heat, who else but Shigao can be relied upon?

For cases transferring from the exterior to the interior, belonging to Shaoyang, the classic text states: "In cold damage or wind strike, with alternating chills and fever, fullness and distress in the chest and hypochondrium, silent desire not to eat, mental irritability, frequent vomiting, or cough," Xiao Chai Hu Tang (Minor Bupleurum Decoction) is modified by removing Renshen (Codonopsis Radix/Panax Ginseng), Dazao (Jujubae Fructus), and Shengjiang (Zingiberis Rhizoma Recens), adding Ganjiang (Zingiberis Rhizoma) and Wuweizi (Schisandrae Fructus). The use of Banxia in Xiao Chai Hu Tang is a sacred medicine for driving out fluid retention. Additionally, Chaihu (Bupleuri Radix) and Huangqin (Scutellariae Radix) harmonize the pathogen at the exterior; Ganjiang and Wuweizi are reused to restrain rebellious Lung Qi. With Huangqin present, Ganjiang is not considered too warming; with Banxia present, Wuweizi is not considered too astringent. Shaoyin is the Water organ, relying entirely on Ministerial Fire to transform Qi, thus having an exterior-interior relationship with Taiyang. If Yang pathogen sinks into Yin causing cough, as stated in the classic: "In Shaoyin disease with cold extremities, if there is occasional cough," Si Ni San (Frigid Extremities Powder) modified with Ganjiang and Wuweizi is used. This is because Yang Qi has sunk into Yin, causing cold extremities; Chaihu is used to stimulate the generating Yang, while Ganjiang and Wuweizi transform fluid retention and calm rebellion. This is a harmonizing formula, not a warming one. If the Ministerial Fire of Shaoyin is diseased itself, as stated: "In Shaoyin disease with diarrhea for six or seven days, cough, vomiting, thirst, mental irritability, and inability to sleep," Zhu Ling Tang (Polyporus Decoction) is used. This has transformed into Yang-heat Qi; the diarrhea is Yang-heat diarrhea. By using Zhu Ling Tang to separate and regulate the water passages, irritability and thirst subside, and both cough and diarrhea cease. All these above are syndromes unsuitable for purely warming treatments. Those requiring urgent warming are like the case stated: "In Shaoyin disease with abdominal pain, difficulty in urination, heaviness and pain in the four limbs, and spontaneous diarrhea," this indicates water qi retention. If there is cough, Zhen Wu Tang (True Warrior Decoction) modified with Wuweizi, Xixin (Asari Radix et Rhizoma), and Ganjiang is used. This is a deficiency-cold syndrome of the Shaoyin organ itself, with Yang decline and Yin excess, requiring urgent warming without doubt.