麻黄（四两去节） 杏仁（五十个） 甘草（二两炙） 石膏（半斤碎绵裹）
上四味。以水七升。先煮麻黄。减二升。去上沫。纳诸药。煮取二升。去滓。温服一升
。
此即麻黄汤去桂枝而加石膏也。即用以治发汗及下后。汗出而喘之证。然必审无大热。
方可
用之。有大热者。恐兼里证。无大热者。明是表邪未彻。留恋在肺。肺主卫。故仍宜麻杏直
泄肺邪。去桂枝者辛热之性。不宜再扰动营血也。加石膏者。降肺金清肃之气。用以生津而
保液也。中风之误下而喘者。用浓朴杏仁加入桂枝汤中。伤寒汗及下后而喘者。用石膏加入
麻黄
汤中。喻嘉言曰。仲景正恐人以伤寒已得汗之证。认为伤风有汗。而误用桂枝。故特出汗后
下后两条。示以同归麻黄一治之要。益见营卫攸分。而成法不容混施矣。
程郊倩曰。喘而汗出脉必浮数。可去桂枝之热。而加石膏之凉亦脉浮数者可发汗之一征
也。
麻黄（六两去节） 桂枝（二两去皮） 甘草（二两炙） 杏仁（五十粒去皮尖） 生姜（三两
切） 大枣（十二枚擘） 石膏（如鸡子大碎）
上七味。以水九升。先煮麻黄。减二升。去上沫。纳诸药。煮取三升。去滓。温服一升
。取微似汗。汗出多者温粉扑之。一服汗者停后服。汗多亡阳遂虚恶风烦躁不得眠也。
此即合麻桂二方。去芍药而加石膏也。按桂枝主风伤卫。麻黄主寒伤营。此则伤风见寒
。伤
寒见风。主大青龙。方中行喻嘉言皆以此分为三大纲。疏太阳上中下三篇。程郊倩谓本论太
阳烦躁一条。系寒温杂邪。温得风而阳热化气。阴寒在表。郁住阳热之气在经。而生烦热。
热则
并扰其阴而作躁。故加石膏于麻黄汤中。使辛热之气变为辛凉。则寒得麻黄汤之辛热而外解
。热得石膏之辛凉而内解。又以伤寒脉浮缓一条。属小青龙汤。大字系坊本之讹。而柯韵伯
又谓此属麻黄证之剧者。由风热相搏。故倍麻黄以发汗。加石膏以除烦。不宜以风寒两伤立
说。愚按经文中风脉浮紧。伤寒脉浮缓。本自回环互说。若拦入温热一路。则温热未有内郁
而不口渴者。何以本文并不言渴。而发热恶寒身疼痛。皆中风伤寒互见
之证。虽烦躁似属热象。亦因不汗出。则风寒之邪无从解。邪无从解。则郁而成热。因致烦
躁。故方中麻桂生姜辛热之药。用至十两有奇。而石膏仅如鸡子大一块。又得甘草大枣相辅
。借其生津之妙用。以作汗而除烦止躁。谨将经文两条阐发于后。
经云。太阳中风。脉浮紧。发热恶寒。身疼痛。不汗出而烦躁者。大青龙汤主之。按太
阳中
风。脉当浮缓。是桂枝汤证。今浮紧是见寒伤营脉。又发热恶寒身疼痛而不汗出。又与中风
之汗自出者不同。不汗出则风邪之伤卫者。得寒凝而多束。寒邪之伤营者。得风拒而内郁。
内烦外躁。正阳气壅遏不宣。将致化热入里之候。治法虽仍不离乎麻黄桂枝而证已见烦躁
。
辛热之性。虑劫伤津液。故加入石膏。且得枣甘相辅。用以生津而保液。此正立方入微入细
处。不可概执石膏为凉解之品也。
又经云。伤寒脉浮缓。身不疼。但重。乍有轻时。无少阴证者。大青龙汤发之。按伤寒
二字
。便已括无汗而喘之证在内。伤寒脉当浮紧。是麻黄汤证。今浮缓是见风伤卫脉。伤寒体重
。身疼腰痛骨节疼痛。今身不疼。但重。乍有轻时。则又非全属伤寒证。其为风寒错杂之邪
显然。以无汗而喘之伤寒病。又得风之阳邪相合。非惟桂枝汤中之芍药不宜用以敛阴。即麻
黄汤之纯行辛热。亦恐有碍风邪。则宜理肺金清肃之气。佐麻桂以驱风散寒。故不得不借资
于
石膏矣。此条徐灵胎疑有错简。程郊倩谓小青龙之误。总由忘却伤寒自有无汗而喘之本证在
。至张令韶又谓此证太阳兼太阴。此方即越脾之义。尤凿。
按大青龙原为阳气壅实。汗不出者立法。若汗出恶风。便是中风之本证。只取和营卫以
解肌
。误服此汤。即致厥逆筋惕肉 种种亡阳之变。然风寒两伤之证。又必辨无少阴证相杂。盖
少阴之脉微细。正恐与太阳浮缓浮弱之脉相混。喻嘉言谓无少阴证。仲景原文。但重乍有轻
时六字。早已挈明。言但身重而无少阴之欲寐。其为寒因可审。况乍有轻时。不似少阴之昼
夜俱重。又兼风因可审。此解颇为入细。至成注谓不久厥吐利。则尤辨证之显者矣
。
再按青龙取义。诸家皆神其说。以形自己一篇绚烂文本。余则谓其理甚庸。试观夏日地
中
之阴气未升。而天上之阳威已极。人在气交之中皆苦炎热。霎时间龙升云兴。滂沱遍野。人
皆精神爽慧也。天地郁蒸。得雨则和。人身烦闷。得汗则解。其理本庸。惟其庸也。正其所
以神乎。
麻黄（四两，去节） 杏仁（五十个） 甘草（二两，炙） 石膏（半斤，碎后用绵布包裹）
以上四味药。用水七升。先煮麻黄。水量减少二升。去掉水面上的浮沫。加入其余药物。煮取药液二升。滤去药渣。温服一升。
这就是麻黄汤去掉桂枝而加上石膏的方子。用来治疗发汗或攻下之后，出现汗出且气喘的症状。但是必须仔细审查没有大热症状，才可以使用该方。如果有大热症状，恐怕兼有里证；如果没有大热症状，说明表邪未完全透解，留恋在肺脏。肺主卫气，所以仍然适宜用麻杏石甘汤直接宣泄肺中的邪气。去掉桂枝是因为其辛热的性质，不宜再扰动营血。加入石膏是为了降敛肺金清肃之气，用以生津并保护津液。中风病误用攻下法导致气喘的，用厚朴、杏仁加入桂枝汤中。伤寒病发汗及攻下后导致气喘的，用石膏加入麻黄汤中。喻嘉言说：张仲景正是担心人们把伤寒已经得汗后的证候，误认为是伤风有汗，从而错误地使用桂枝汤。所以特意列出汗后和下后两条条文，提示它们最终都归于使用麻黄类方治疗的要点。这更显示出营气和卫气的区分，使得既定法则不容混淆施用。
程郊倩说：气喘且汗出，脉象必然浮数，可以去除桂枝的热性，而加入石膏的凉性。脉象浮数也是可以使用发汗法的一个征象。
麻黄（六两，去节） 桂枝（二两，去皮） 甘草（二两，炙） 杏仁（五十粒，去皮尖） 生姜（三两，切片） 大枣（十二枚，掰开） 石膏（如鸡蛋大小，捣碎）
以上七味药。用水九升。先煮麻黄。水量减少二升。去掉水面上的浮沫。加入其余药物。煮取药液三升。滤去药渣。温服一升。服用后取得微微似出汗的效果。如果汗出过多，用温粉扑洒身体。服用一次后若已出汗，则停止后续服药。如果汗出过多导致阳气亡失，进而虚弱，出现怕风、烦躁、无法入睡等症状。
这就是将麻黄汤和桂枝汤两个方子合并，去掉芍药而加上石膏的方子。按：桂枝主治风邪伤卫，麻黄主治寒邪伤营。此方则是伤风见寒象，伤寒见风象，主治大青龙汤。方中行、喻嘉言都将此分为三个大纲，疏解太阳篇的上、中、下三部分。程郊倩认为《伤寒论》太阳篇中关于“烦躁”的一条，属于寒温杂合之邪。温邪遇风则阳热化气，阴寒在体表，郁阻了阳热之气在经脉中运行，从而产生烦热。热邪则会同时扰动阴分而导致躁动。所以在麻黄汤中加入石膏，使辛热的药性变为辛凉。这样，寒邪借助麻黄汤的辛热而在体外解除，热邪借助石膏的辛凉而在体内解除。又有观点认为伤寒脉浮缓一条属于小青龙汤，“大”字是坊间刻本的讹误。而柯韵伯又认为这属于麻黄证的剧烈情况，由风热相搏所致，所以加倍使用麻黄以发汗，加入石膏以除烦。不应当以风寒两伤立论。我认为经文中说中风脉浮紧，伤寒脉浮缓，本是互相回转互说的。如果强行引入温热病的思路，那么温热病没有内郁而不口渴的。为什么本文并不提及口渴，而发热恶寒身疼痛，都是中风和伤寒互相夹杂的证候。虽然烦躁似乎属于热象，也是因为无汗，导致风寒之邪无从解除。邪气无从解除，就会郁结而成热，因此导致烦躁。所以方中麻黄、桂枝、生姜等辛热的药物，用量达到十两以上，而石膏仅如鸡蛋大小一块。再加上甘草、大枣相辅助，借其生津的妙用，通过作汗来消除烦躁和躁动。谨将经文两条阐发如下。
经文说：太阳中风，脉象浮紧，发热恶寒，身体疼痛，无汗且烦躁的，用大青龙汤主治。按：太阳中风，脉象应当浮缓，这是桂枝汤的证候。现在脉象浮紧，是见到寒伤营的脉象。又有发热恶寒身体疼痛且无汗，又与中风自汗出的情况不同。无汗则风邪伤卫者，得寒凝滞而更加束缚；寒邪伤营者，得风抗拒而内部郁结。内烦外躁，正是阳气壅遏不能宣通，将要导致化热入里的征兆。治法虽然仍不离乎麻黄、桂枝，但证候已经出现烦躁。辛热的药性，担心会劫伤津液，所以加入石膏。并且得到枣、甘相辅助，用以生津并保护津液。这正是立方细微精到处，不可一概执着于石膏为凉解之品。
又经文说：伤寒脉象浮缓，身体不疼，只是沉重，偶尔有减轻的时候，没有少阴证候的，用大青龙汤发散。按：“伤寒”二字，已经包含无汗而喘的证候在内。伤寒脉象应当浮紧，这是麻黄汤的证候。现在脉象浮缓，是见到风伤卫的脉象。伤寒体重，身体疼痛腰痛骨节疼痛。现在身体不疼，只是沉重，偶尔有减轻的时候，那么又不完全属于伤寒证。其为风寒错杂之邪显然。以无汗而喘的伤寒病，又得风的阳邪相结合，不仅桂枝汤中的芍药不宜用来收敛阴气，就是麻黄汤纯行辛热，也恐怕有碍于风邪。则应该调理肺金清肃之气，辅助麻黄、桂枝以驱风散寒。所以不得不借助于石膏了。这一条徐灵胎怀疑有错简。程郊倩认为是小青龙汤的误写，总归是因为忘记了伤寒自有无汗而喘的本证存在。至于张令韶又认为此证是太阳兼太阴，此方即越脾的意思，尤为牵强。
按：大青龙汤原本是为阳气壅实、无汗的人设立的法则。如果汗出怕风，便是中风的本证，只需调和营卫以解肌。误服此汤，就会导致四肢厥逆、筋惕肉等多种阳气亡失的变化。然而风寒两伤的证候，又必须辨别没有少阴证混杂。因为少阴的脉象微细，正担心与太阳浮缓、浮弱的脉象相混淆。喻嘉言说“无少阴证”，张仲景原文中“但重乍有轻时”六个字，早已明确提出来了。意思是只有身体沉重而没有少阴病的嗜睡欲寐，其为寒因可以审察。况且偶尔有减轻的时候，不像少阴病昼夜都沉重，又是风因可以审察。这种解释颇为细致。至于成无己注解说不久会出现厥逆吐利，则是辨证明显的表现啊。
再按：青龙取义，各家都将其神化。从自己的一篇绚烂文本来看，我却认为其道理很平常。试看夏日地下的阴气尚未升起，而天上的阳气威势已达极致。人在气交之中都苦于炎热。霎时间龙升云兴，大雨滂沱遍野，人都感到精神爽慧。天地郁蒸，得雨则调和。人身烦闷，得汗则解除。其道理本来很平常。正因为其平常，正是它神奇的地方。
Ephedrae Herba (Mahuang, 麻黄) [4 liang, nodes removed], Armeniacae Semen Amarum (Xingren, 杏仁) [50 seeds], Glycyrrhizae Radix et Rhizoma Preparata (Gancao Zhi, 甘草, prepared) [2 liang], Gypsum Fibrosum (Shigao, 石膏) [half jin, crushed and wrapped in cotton].
The above four ingredients. Use seven sheng of water. First decoct Ephedrae Herba until the volume reduces by two sheng. Remove the foam on the surface. Add the remaining herbs. Decoct to obtain two sheng of liquid. Filter out the dregs. Take one sheng warm.
This is essentially Mahuang Tang (Ephedra Decoction) with Gui Zhi (Cinnamon Twig) removed and Shigao (Gypsum) added. It is used to treat conditions characterized by sweating and wheezing after inducing sweating or purging. However, one must carefully examine that there is no significant heat before using it. If there is significant heat, it is feared that there may be a interior syndrome. The absence of significant heat indicates that the exterior pathogen has not been fully resolved and remains lingering in the Lung. The Lung governs Wei Qi (Defensive Qi), so it is still appropriate to use Mahuang Xingren Gancao Shigao Tang directly to vent the pathogenic factors from the Lung. Gui Zhi is removed because its acrid-warm nature should not further disturb Ying Blood (Nutritive Blood). Shigao is added to descend the clear and descending Qi of Metal (Lung), thereby generating fluids and protecting body fluids. For wheezing caused by mistaken purging in Wind Strike (Zhong Feng), Houpo (Magnolia Bark) and Xingren are added to Guizhi Tang (Cinnamon Twig Decoction). For wheezing after sweating and purging in Cold Damage (Shang Han), Shigao is added to Mahuang Tang. Yu Jiayan stated: Zhang Zhongjing was particularly concerned that people might mistake the post-sweating condition of Shang Han for the sweating condition of Shang Feng (Wind Injury) and mistakenly use Guizhi Tang. Therefore, he specifically listed the clauses regarding post-sweating and post-purging to show that they both converge on the essential treatment using Mahuang-based formulas. This further highlights the distinction between Ying and Wei, making it clear that established methods should not be mixed indiscriminately.
Cheng Jiaoqian stated: Wheezing accompanied by sweating implies a floating and rapid pulse. One can remove the heat of Gui Zhi and add the coolness of Shigao. A floating and rapid pulse is also one sign indicating that sweating therapy can be applied.
Ephedrae Herba (Mahuang, 麻黄) [6 liang, nodes removed], Cinnamomi Ramulus (Guizhi, 桂枝) [2 liang, bark removed], Glycyrrhizae Radix et Rhizoma Preparata (Gancao Zhi, 甘草, prepared) [2 liang], Armeniacae Semen Amarum (Xingren, 杏仁) [50 seeds, skin and tips removed], Zingiberis Rhizoma Recens (Shengjiang, 生姜) [3 liang, sliced], Ziziphi Jujubae Fructus (Dazao, 大枣) [12 pieces, split], Gypsum Fibrosum (Shigao, 石膏) [size of a chicken egg, crushed].
The above seven ingredients. Use nine sheng of water. First decoct Ephedrae Herba until the volume reduces by two sheng. Remove the foam on the surface. Add the remaining herbs. Decoct to obtain three sheng of liquid. Filter out the dregs. Take one sheng warm. Aim for a slight, uniform sweating. If sweating is excessive, apply warm powder to the body. If sweating occurs after the first dose, stop taking the remaining medicine. Excessive sweating leading to Yang collapse results in deficiency, aversion to wind, irritability, and inability to sleep.
This combines the two formulas of Mahuang Tang and Guizhi Tang, removing Shaoyao (Paeonia Root) and adding Shigao. Note: Guizhi treats Wind injuring Wei; Mahuang treats Cold injuring Ying. This formula addresses cases where Wind injury presents with Cold signs, and Cold injury presents with Wind signs, primarily treating Da Qing Long Tang (Major Blue Dragon Decoction). Fang Zhongxing and Yu Jiayan divided this into three main outlines, explaining the Upper, Middle, and Lower sections of the Taiyang chapter. Cheng Jiaoqian believed that the clause regarding "irritability" in the Taiyang chapter of the Treatise belongs to mixed Cold and Warm pathogens. Warm pathogens encountering Wind transform into Yang-Heat Qi. Yin-Cold at the exterior obstructs the Yang-Heat Qi in the meridians, generating irritability and heat. Heat disturbs the Yin, causing restlessness. Therefore, Shigao is added to Mahuang Tang to change the acrid-warm nature to acrid-cool. Thus, Cold is resolved externally via the acrid-warm nature of Mahuang Tang, and Heat is resolved internally via the acrid-cool nature of Shigao. Another view holds that the clause "Cold Damage with floating and slow pulse" belongs to Xiao Qing Long Tang (Minor Blue Dragon Decoction), and the character "Da" (Major) is an error in commercial editions. Ke Yunbo argued that this belongs to severe cases of Mahuang patterns, caused by the struggle between Wind and Heat, hence doubling Mahuang to induce sweating and adding Shigao to relieve irritability. He opposed the theory of dual injury by Wind and Cold. I believe that in the classic text, stating Wind Strike has a floating-tight pulse and Cold Damage has a floating-slow pulse is a reciprocal explanation. If one forcibly introduces the path of Warm Diseases, there are no internal-stagnant Warm Disease cases without thirst. Why does this text not mention thirst? Fever, aversion to cold, and body pain are mutually overlapping signs of Wind Strike and Cold Damage. Although irritability seems like a heat sign, it is due to the lack of sweating, preventing the resolution of Wind-Cold pathogens. Without pathogen resolution, stagnation generates heat, leading to irritability. Therefore, in the formula, the acrid-warm drugs Mahuang, Guizhi, and Shengjiang total over ten liang, while Shigao is only the size of a chicken egg. Assisted by Gancao and Dazao, borrowing their fluid-generating efficacy, sweat is produced to relieve irritability and restlessness. I hereby elucidate the two classic clauses below.
The Classic states: In Taiyang Wind Strike, if the pulse is floating-tight, with fever, aversion to cold, body pain, no sweating, and irritability, Da Qing Long Tang is the primary treatment. Note: In Taiyang Wind Strike, the pulse should be floating-slow, which is a Guizhi Tang pattern. Now, a floating-tight pulse indicates Cold injuring Ying. Furthermore, fever, aversion to cold, body pain, and no sweating differ from the spontaneous sweating of Wind Strike. No sweating means the Wind pathogen injuring Wei is constrained by Cold; the Cold pathogen injuring Ying is resisted by Wind and internally stagnant. Internal irritability and external restlessness indicate Yang Qi obstruction and failure to diffuse, a precursor to transformation into Heat entering the interior. Although the treatment method still relies on Mahuang and Guizhi, the appearance of irritability suggests caution against the acrid-warm nature劫ting fluids. Thus, Shigao is added. Assisted by Zao and Gancao, it generates fluids and protects them. This is the subtle detail in formulating the prescription; one cannot simply regard Shigao as merely a cooling agent.
Again, the Classic states: In Cold Damage, if the pulse is floating-slow, the body is not painful but heavy, occasionally feeling lighter, and there are no Shaoyin signs, Da Qing Long Tang is used to disperse. Note: The term "Cold Damage" inherently includes the pattern of no sweating and wheezing. In Cold Damage, the pulse should be floating-tight, a Mahuang Tang pattern. Now, a floating-slow pulse indicates Wind injuring Wei. In Cold Damage, heaviness involves body pain, lower back pain, and joint pain. Here, the body is not painful, only heavy, occasionally lighter, indicating it is not entirely a Cold Damage pattern. It is clearly mixed Wind-Cold pathogens. Combining the Cold Damage of no sweating and wheezing with the Yang pathogen of Wind, not only is Shaoyao in Guizhi Tang unsuitable for astringing Yin, but the purely acrid-warm nature of Mahuang Tang might also hinder the Wind pathogen. Thus, one should regulate the clear-descending Qi of Lung Metal, assisting Mahuang and Guizhi to dispel Wind and scatter Cold. Hence, reliance on Shigao becomes necessary. Xu Lingtai suspected textual errors in this clause. Cheng Jiaoqian attributed it to a mistake for Xiao Qing Long Tang, forgetting that Cold Damage naturally has the fundamental pattern of no sweating and wheezing. Zhanglingshao argued this pattern involves Taiyang combining with Taiyin, and the formula implies Yue Pi (transcending Spleen), which is overly forced.
Note: Da Qing Long Tang was originally established for cases of Yang Qi congestion and excess with no sweating. If there is sweating and aversion to wind, it is the fundamental pattern of Wind Strike, requiring only harmonization of Ying and Wei to resolve the muscle layer. Mistaken use of this decoction leads to reversal cold, twitching of sinews, and various signs of Yang collapse. However, for dual injury by Wind and Cold, one must distinguish the absence of mixed Shaoyin signs. Shaoyin pulses are fine and minute, easily confused with the floating-slow or floating-weak pulses of Taiyang. Yu Jiayan stated that "no Shaoyin signs," clarified by the six characters "only heavy, occasionally lighter" in Zhang Zhongjing's original text, already makes this clear. It means only body heaviness without the lethargy/desire to sleep of Shaoyin confirms the Cold cause. Moreover, occasional lightness contrasts with Shaoyin's constant heaviness day and night, confirming the Wind cause. This interpretation is quite detailed. Cheng Wuji's note that reversal cold, vomiting, and diarrhea will occur soon is a clear manifestation of differentiation.
Furthermore, regarding the symbolism of Qing Long (Blue Dragon), scholars have mystified it. From my own elaborate text, I consider the principle quite mundane. Observe summer: Yin Qi underground has not risen, yet Yang power in the sky is extreme. Humans in the qi intersection suffer heat. Suddenly, the dragon rises, clouds gather, rain floods the fields, and humans feel refreshed. Heaven and Earth, stiflingly hot, become harmonious with rain. The human body, stuffy and irritable, resolves with sweat. The principle is fundamentally mundane. Precisely because it is mundane, it is what makes it miraculous.