寒邪伤人阳气，郁而成热，皮肤闭而成实，麻黄轻以去实，辛以发阳气，温以散寒气。
杏仁佐麻黄通肺气，使腠理开泄，王好古谓其为治卫实之药者是也。然泄而不收、升而不降，桂
枝、甘草虽以佐之，实监制之耳！东垣云∶麻黄汤是阳经卫药也，开腠理使阳气申泄，此药
为卫实也。
大青龙治风寒外壅，而闭热于经者；小青龙治风寒外壅，而伏饮于内者。夫热郁于经，
而不
用石膏，汗为热隔，宁有能发之者乎？饮伏于内，而不用姜、夏，邪与饮抟，宁有能散之者
乎？其芍药、五味，不特靖逆气而安肺气，抑且制麻、桂、姜、辛之势，使不相 而相就，
以成内外协济之功也。
伤寒脉浮，医以火迫劫之亡阳，必惊狂、起卧不安者，桂枝去芍药加蜀漆龙骨牡蛎救逆
汤主
之。按此所谓阳者，乃心之阳，盖即神也。火气通于心，神被迫而不收，与发汗亡阳者不同
。发汗者，动其肾，则厥逆、筋惕肉 ，故当用四逆；被火者，伤其心，则惊狂、起卧不安
，故当用龙、牡。其去芍药，加蜀漆者，盖欲甘辛急复心阳，而不须酸味更益营气也。与发
汗后，其人叉手自冒心、心下悸欲得按者，用桂枝甘草汤同。蜀漆即常山苗，味辛，能去胸
中邪结气。此症火气内逼心包，故须以逐邪而安正耳！
寒邪侵袭人体，损伤阳气，导致阳气郁结而化热，皮肤腠理闭塞而形成实证。麻黄药性轻扬，能祛除实邪；其味辛，能发散阳气；其性温，能驱散寒气。
杏仁辅助麻黄疏通肺气，使腠理开泄，王好古称其为治疗卫分实证的药物，正是此意。然而，若只泄不敛、只升不降，桂枝和甘草虽然起到辅助作用，实际上更多是起制约和监制的作用！李东垣说：麻黄汤是阳经治疗卫分的药物，开启腠理使阳气得以宣发疏泄，这是针对卫分实证的用药。
大青龙汤治疗风寒外束，导致热邪闭郁在经脉中的病证；小青龙汤治疗风寒外束，同时体内潜伏水饮的病证。如果热邪郁结在经脉中，却不用石膏，汗液被热邪阻隔，难道还有能发汗的吗？如果水饮潜伏在体内，却不用干姜、半夏，邪气与水饮搏结，难道还有能消散的吗？方中的芍药、五味子，不仅能平息逆气、安定肺气，而且能制约麻黄、桂枝、干姜、细辛的峻烈之势，使它们不相冲突而相互协同，从而达成内外协济的功效。
伤寒脉象浮，医生用火法强迫发汗，导致亡阳，必然出现惊悸狂乱、坐卧不安的症状，应当用桂枝去芍药加蜀漆龙骨牡蛎救逆汤主治。按：这里所说的“阳”，指的是心之阳，也就是心神。火气通于心，心神被火邪逼迫而不能收敛，这与发汗导致的亡阳不同。发汗过度，动摇的是肾阳，会出现四肢厥冷、筋肉跳动等症状，所以应当用四逆汤；被火邪所伤，损伤的是心阳，会出现惊悸狂乱、坐卧不安，所以应当用龙骨、牡蛎。去掉芍药，加入蜀漆，是因为想要用甘辛之品迅速恢复心阳，而不需要酸味药物进一步增益营气。这与发汗后，病人双手交叉护住心前区、心下悸动且喜欢按压的情况，使用桂枝甘草汤的道理相同。蜀漆就是常山的嫩苗，味辛，能去除胸中的邪气结聚。此症是火邪内逼心包，所以需要用逐邪的药物来安定正气罢了！
Cold pathogenic factors invade the human body, damaging Yang Qi (Yang energy), causing it to stagnate and transform into heat. The skin and pores become closed, leading to an excess syndrome. Ephedrae Herba (Mahuang, 麻黄) is light in nature to dispel excess; its pungent flavor disperses Yang Qi; its warm property scatters cold pathogens.
Prunus Armeniaca Seed (Xingren, 杏仁) assists Ephedrae Herba in unblocking Lung Qi, allowing the pores to open and release. Wang Haogu described it as a medicine for treating excess in the Wei (Defensive) level, which is accurate. However, if there is only dispersion without retention, and only ascending without descending, although Cinnamon Twig (Guizhi, 桂枝) and Licorice Root (Gancao, 甘草) serve as assistants, they essentially act as regulators and controllers! Li Dongyuan stated: Mahuang Tang (Ephedra Decoction) is a Wei-level medicine for the Yang meridians; it opens the pores to allow Yang Qi to be ventilated and released, addressing excess in the Wei level.
Da Qing Long Tang (Major Blue-Green Dragon Decoction) treats exterior constraint by wind-cold with heat trapped within the meridians; Xiao Qing Long Tang (Minor Blue-Green Dragon Decoction) treats exterior constraint by wind-cold with retained fluid-phlegm inside. If heat is stagnant in the meridians but Gypsum (Shigao, 石膏) is not used, how can sweat be released when it is blocked by heat? If fluid-phlegm is retained internally but Dried Ginger (Ganjiang, 干姜) and Pinellia Tuber (Banxia, 半夏) are not used, how can the pathogen and fluid-phlegm be dispersed when they knot together? Schisandra Fruit (Wuweizi, 五味子) and Peony Root (Shaoyao, 芍药) not only calm rebellious Qi and stabilize Lung Qi, but also restrain the vigorous effects of Ephedrae Herba, Cinnamon Twig, Dried Ginger, and Asarum Root (Xixin, 细辛), preventing conflict and promoting synergy, thereby achieving cooperative effects inside and outside.
In Shanghan (Cold Damage) with a floating pulse, if a physician uses fire therapy to force sweating, resulting in the loss of Yang, symptoms such as fright, mania, restlessness, and inability to lie still will inevitably occur. This should be treated with Guizhi Qu Shaoyao Jia Shuqi Longgu Muli Jiuniu Tang (Cinnamon Twig Decoction without Peony plus Dichroa Root, Dragon Bone, and Oyster Shell to Rescue from Deviation). Note: The "Yang" mentioned here refers to Heart Yang, which is essentially Shen (Spirit/Mind). Fire pathogenic factors communicate with the Heart; when Shen is forced by fire and cannot consolidate, it differs from Yang loss due to excessive sweating. Excessive sweating disturbs Kidney Yang, leading to cold extremities and muscle twitching, thus requiring Sini Tang (Frigid Extremities Decoction). Injury by fire damages Heart Yang, leading to fright, mania, and restlessness, thus requiring Dragon Bone (Longgu, 龙骨) and Oyster Shell (Muli, 牡蛎). Removing Peony and adding Dichroa Root aims to use sweet and pungent flavors to rapidly restore Heart Yang, avoiding sour flavors that would further nourish Ying (Nutritive) Qi. This parallels the case after sweating where the patient crosses their hands over the heart, experiences palpitations under the epigastrium, and desires pressure, treated with Guizhi Gancao Tang (Cinnamon Twig and Licorice Decoction). Shuqi is the young shoot of Dichroa Febrifuga Radix (Changshan, 常山); it is pungent and can remove pathological qi accumulation in the chest. In this condition, fire forces inwardly into the Pericardium, so one must use herbs that expel pathogens to stabilize healthy Qi.