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Treating cold damage (Shanghan) with no sweating.
Ephedrae Herba (Mahuang, 麻黄) (4 qian), Cinnamon Twig (Guizhi Jians, 桂枝尖) (2 qian), Licorice Root (Gancao, 甘草) (1 qian), Apricot Seed (Xingren, 杏仁) (2 qian, peeled and stir-fried), Anemarrhenae Rhizoma (Zhimu, 知母) (3 qian).
First decoct Ephedrae Herba for five or six boils, remove the foam on the surface, then add the remaining herbs and decoct to obtain one teacup of liquid. Take warm, cover with a blanket to induce slight perspiration; there is no need to drink hot porridge. The rest of the nursing care follows the method of Guizhi Tang (Cinnamon Twig Decoction).
In the original formula of Mahuang Tang (Ephedra Decoction), the instruction "remove skin" under Guizhi does not refer to removing the bark from the twig. In ancient times, when using Guizhi, only the tender tips and branches were selected. When broken, the interior and exterior appeared uniform, with no distinction between bark and wood. If bark and wood could be distinguished, they were discarded. Hence it is called "remove skin." Chen Xiuyuan's nephew, Chen Mingqi, discussed this in detail.
In the Taiyang Chapter of Shanghan Lun (Treatise on Cold Damage), Mahuang Tang originally appeared after Guizhi Tang. However, indications for Mahuang Tang are more common than those for Guizhi Tang, which account for only one or two out of ten cases. Moreover, since the disease is named "cold damage," and Mahuang Tang is the primary formula for treating early-stage cold damage, it is recorded first here.
The pathogenesis of cold damage begins with the back receiving the pathogen. The back is the area governed by the Foot-Taiyang Bladder Channel. Therefore, at the onset, although the whole body experiences aversion to cold, the aversion to cold in the back is particularly severe; although the whole body feels painful, the pain extending from the back down to the legs is particularly severe. A pulse that is tight and forceful at both cun and chi positions occurs because the Taiyang channel represents the defensive yang of the entire body. Sudden invasion by wind-cold forces the yang qi to sink inward, merging with the vessel, making the pulse forceful and exhibiting a surging, undulating momentum. However, the contracting power of cold (whereby matter expands when heated and contracts when cooled) tightens the defensive qi externally, compressing the vessels so they cannot undulate into waves, presenting instead as wiry, straight, and forceful. In extreme cases, due to the inability to undulate, the pulse may exhibit lateral flickering.
A tight pulse is invariably forceful. The beating of the pulse is governed by the Heart. However, its forcefulness is not solely determined by the Heart; heat in any zang-fu organ can assist in making the pulse beat forcefully, as can heat within the Ying and Wei (nutritive and defensive) levels. Specifically, a forceful pulse often resembles water with waves, showing significant undulation. Although a tight pulse is forceful, it appears to lack undulation. This is because severe cold binds the exterior; its contracting power forces the heat of Ying and Wei to sink inward and merge with the vessel, enhancing its forcefulness, while simultaneously suppressing the pulsation, preventing undulation. Thus, the true nature of a tight pulse manifests as forcefulness amidst parallel tension. Lateral flickering in a tight pulse is also a sign of accumulation reaching an extreme and overflowing laterally. Zhang Zhongjing treated this with Mahuang Tang to release the cold binding the exterior.
In this formula, Mahuang, characterized by its hot nature and hollow structure, directly travels along the Taiyang channel, reaches the exterior skin and hair, and expels external cold through diaphoresis. Guizhi, being acrid, warm, and slightly sweet, works together with Gancao to warm the muscles and solidify the cou li (interstices), assisting Mahuang in pushing the cold outward. Xingren, being bitter and descending, enters the chest to direct rebellious qi downward and calm wheezing. The original formula contains only these four herbs. I added ZhiMu because, after taking this decoction, there are occasional cases where sweating fails to resolve the condition. This is not due to incomplete sweating, but rather because residual heat remains unclarified. By adding ZhiMu among the dispersing herbs, the intention of clearing heat is incorporated, eliminating the risk of unresolved symptoms after sweating. This conclusion is based on repeated clinical trials and confirmed efficacy; I dare not lightly modify classical formulas.
One might ask: Wheezing is a disease of the Lung, yet the Taiyang channel has no direct connection to the Lung, why do many cases present with mild wheezing? The answer is: The chest is also part of the Taiyang region. The great qi accumulated there communicates continuously with the defensive qi of the body. Once the defensive qi is bound by cold, the great qi becomes internally stagnant, inevitably expanding and rebelling upward to rush against the Lung, causing wheezing. Furthermore, wind-cold invading the skin and hair necessarily affects the Hand-Taiyin Lung Channel, carrying phlegm-fluids to condense and obstruct the lung orifices, which is another cause of wheezing. Mahuang can enter the Hand-Taiyin channel to disperse wind-cold within it and can also penetrate directly into the Lung to drain stagnation and fullness. Thus, Mahuang is not the only herb capable of inducing sweating in the Taiyang channel. Zhang Zhongjing uniquely selected Mahuang, primarily a drug for the Foot channels, while ensuring comprehensive coverage of the Hand channels. This demonstrates the subtlety of Zhang Zhongjing's formula construction.
Herbs that promote urination and have a hollow structure often also induce sweating, such as Plantaginis Semen (Cheqianzi, 车前子 - *Note: Text says 'Xu' likely referring to Cheqiancao/Plantago leaf or similar, but standard translation for context of hollow/diuretic often implies Plantago or similar. Given 'Xu' might be a typo for 'Cheqian' or specific local herb, I will translate generally as herbs promoting urination*) and Tongcao (Mutong, 木通). Conversely, diaphoretic herbs with a hollow structure often also promote urination, such as Mahuang and Chaihu (Bupleuri Radix, 柴胡). Diseases of the Taiyang channel often involve the Bladder, as the Bladder is the fu-organ of the Taiyang. Mahuang Tang treats pathogens in the Taiyang channel; it also addresses pathogens in the fu-organ. Pathogens in the channel are resolved through sweating, while pathogens in the fu-organ can be resolved through urination. Later generations, acting cleverly, often substitute other herbs for Mahuang Tang, failing to fully appreciate this principle.
Da Qing Long Tang (Major Blue Green Dragon Decoction) treats cold damage with no sweating and irritability. This indicates pre-existing internal heat in the chest that has no outlet, leading to stagnation and irritability. Therefore, Shi Gao (Gypsum Fibrosum, 石膏) is added to the exterior-releasing herbs to clear internal heat. However, when Mahuang and Shi Gao are used together, sweating may occasionally fail to occur. If using this formula, increasing the dose of ZhiMu by several qian allows its cold and moistening nature to enter the chest, combine into fluid, and travel outward with Mahuang and Guizhi, thereby resolving irritability.
Cold damage (Shanghan) and warm diseases (Wenbing) start differently but end similarly. Because they start differently, exterior-releasing treatment for cold damage can use warm-hot herbs, whereas for warm diseases, acrid-cool herbs must be used. Because they end similarly, once the disease transmits to the Yangming stage, regardless of whether it originated as cold or warm, cold-cool herbs should be used, and warm-hot herbs are strictly contraindicated. In this compilation, within the exterior-releasing category, I have briefly selected several formulas from the Taiyang Chapter of Shanghan Lun and provided some explanations, so that beginners understand that the treatment for early-stage cold damage differs from that of warm diseases, thereby further realizing that the treatment for early-stage warm diseases differs from that of cold damage. As for the treatment of the Three Yin stages in cold damage, although it differs significantly from warm diseases, such cases are rare. If expanded upon, conditions such as cholera and sand-stroke caused by cold seem to be included within this scope. The principles are profound and extensive, impossible to exhaust in thousands of words. Those wishing to master this field should study the original text carefully.