麻黄（三两去节） 桂枝（二两） 甘草（一两炙） 杏仁（七十个泡去皮尖）
上四味以水九升。先煮麻黄减二升。去上沫。纳诸药煮取二升半。去滓温服八合覆取微似汗不须啜粥余如桂枝法将
息。
夫寒伤营。则营血受病而见骨节烦疼。当矣何反腠理闭密无汗而喘耶盖营既受伤于内。必无卫气独和于外之理所以
用麻黄发汗必兼桂枝以和营。用杏仁者。所以散气除喘用甘草者。所以助阳和卫。营卫流行始能作汗也。按时珍云。仲
景治伤寒无汗。用麻黄有汗用桂枝。历代名医未有究其精微者。夫津液为汗。汗即血也。在营即为血在卫即为汗。寒伤
营。营血不能外通于卫。卫气闭固。故无汗发热而增寒。风伤卫。卫气不能内护于营。营气不固。故有汗发热恶风是麻
黄汤虽太阳发汗重剂。实为发散肺经火郁之药。桂枝汤虽太阳解肌轻剂。实为理脾救肺之药也。又汪石山云。辛甘发散
为阳。仲景发表药中。必用甘草以载住邪气不使陷入阴分也。若邪既入里。则内 张必无复用甘草之理试观五苓抵当承
气大柴陷胸十枣辈并不用甘草也。惟调胃桃核二汤以其尚兼太阳部分之表邪。故不得不用也。当知发汗药中之甘草。必
不可少。此汤须脉证全在于表方可用之。若脉微弱自汗者不可用也。今人但执一二日在表。并宜发汗。设尺中弦数虚大。
为阴虚多火汗之则亢阳热厥而死尺中迟弱足冷。为阳虚夹阴汗之。则亡阳。厥逆而死。可不慎欤。
麻黄（三两，去节） 桂枝（二两） 甘草（一两，炙） 杏仁（七十个，泡后去皮尖）
以上四味药，用九升水。先煮麻黄，水量减少二升，撇去水面上的浮沫，加入其余药物，煎取二升半药液，滤去药渣，温服八合，服药后覆盖衣被以取得微微似有汗出的效果，不需要喝热粥，其余调养方法参照桂枝汤法。
寒邪损伤营分，则营血受病而出现骨节烦痛，这是应当的。为何反而出现腠理闭塞、无汗而喘呢？大概是因为营气既已在内受伤，必然没有卫气独自在外调和的道理。所以使用麻黄发汗，必须兼用桂枝来调和营气；使用杏仁，是用来散气除喘；使用甘草，是用来助阳和卫。只有营卫之气流通，才能产生汗液。据李时珍所说，张仲景治疗伤寒无汗，用麻黄汤；有汗，用桂枝汤。历代名医未曾探究其中的精微之处。津液化为汗，汗即血也。在营分即为血，在卫分即为汗。寒邪伤及营分，营血不能外通于卫分，卫气闭固，所以无汗、发热且恶寒加重。风邪伤及卫分，卫气不能内护于营分，营气不固，所以有汗、发热且恶风。因此，麻黄汤虽然是太阳经发汗的重剂，实际上是发散肺经火郁的药物；桂枝汤虽然是太阳经解肌的轻剂，实际上是调理脾胃、救助肺脏的药物。又据汪石山说，辛甘发散为阳。张仲景在发表药中，必定使用甘草来留住邪气，不使其陷入阴分。如果邪气已经入里，则内部胀满，必定没有再复用甘草的道理。试看五苓散、抵当汤、承气汤、大柴胡汤、陷胸汤、十枣汤等方剂，都不使用甘草。只有调胃承气汤和桃核承气汤，因为它们尚兼有太阳部分的表邪，所以不得不使用甘草。应当知道，发汗药中的甘草，是绝对不可少的。此汤必须在脉证完全在表的情况下方可使用。如果脉微弱、自汗出，则不可使用。现在的人只执着于发病一二日且在表，都适宜发汗。假如尺部脉弦数虚大，这是阴虚多火，发汗则会导致亢阳、热厥而死；尺部脉迟弱、足冷，这是阳虚夹阴，发汗则会导致亡阳、厥逆而死。能不谨慎吗？
Ephedrae Herba (Mahuang, 麻黄) three liang, remove nodes; Cinnamomi Ramulus (Guizhi, 桂枝) two liang; Glycyrrhizae Radix et Rhizoma (Gancao, 甘草) one liang, honey-fried; Armeniacae Semen Amarum (Xingren, 杏仁) seventy seeds, soaked, peel and remove sharp tips.
Take the above four ingredients, add nine sheng of water. First decoct Ephedrae Herba until the volume decreases by two sheng, skim off the foam on the surface, then add the remaining herbs. Decoct to obtain two and a half sheng of liquid, strain out the dregs, and take eight ge warm. Cover with blankets to induce a slight perspiration resembling moisture; there is no need to drink hot porridge. Other post-medication care should follow the method of Guizhi Tang (Cinnamon Twig Decoction).
When cold pathogen injures Ying (Nutritive Qi), Ying blood suffers disease, resulting in painful joints; this is expected. Why, however, does it present with closed pores, anhidrosis, and wheezing? Since Ying has been injured internally, it is impossible for Wei (Defensive Qi) to remain harmonious externally alone. Therefore, Mahuang Tang (Ephedra Decoction) uses Ephedrae Herba to induce sweating, combined with Cinnamomi Ramulus to harmonize Ying. Armeniacae Semen Amarum is used to dissipate Qi and relieve wheezing; Glycyrrhizae Radix et Rhizoma is used to assist Yang and harmonize Wei. Only when Ying and Wei circulate freely can sweat be produced. According to Li Shizhen, Zhang Zhongjing used Mahuang Tang for cold-induced anhidrosis and Guizhi Tang for sweating. Past renowned physicians have not thoroughly investigated its subtleties. Body fluids transform into sweat; sweat is essentially blood. Within Ying, it is blood; within Wei, it is sweat. When cold injures Ying, Ying blood cannot communicate outwardly with Wei, causing Wei Qi to close and secure, leading to anhidrosis, fever, and increased aversion to cold. When wind injures Wei, Wei Qi cannot protect Ying inwardly, causing Ying Qi to be insecure, leading to sweating, fever, and aversion to wind. Thus, although Mahuang Tang is a heavy sweating formula for Taiyang (Greater Yang) disorders, it is actually a medication to disperse fire stagnation in the Lung channel. Although Guizhi Tang is a light muscle-releasing formula for Taiyang disorders, it is actually a medication to regulate the Spleen and rescue the Lung. Furthermore, Wang Shishan stated that pungent and sweet flavors disperse and belong to Yang. In Zhang Zhongjing’s exterior-releasing formulas, Glycyrrhizae Radix et Rhizoma is always used to retain the pathogenic factor and prevent it from sinking into the Yin levels. If the pathogen has entered the interior, causing abdominal fullness, there would be no reason to reuse Glycyrrhizae Radix et Rhizoma. Observe formulas such as Wuling San (Poria Powder), Dandang Tang (Tigernut Tuber Decoction), Chengqi Tang (Order the Qi Decoction), Daxiehu Tang (Major Bupleurum Decoction), Xiongxian Tang (Chest Trap Decoction), and Shizao Tang (Ten Jujube Decoction); none use Glycyrrhizae Radix et Rhizoma. Only Tiaowei Chengqi Tang (Regulate the Stomach Order the Qi Decoction) and Taohe Chengqi Tang (Peach Kernel Order the Qi Decoction) use it because they still involve exterior pathogens of the Taiyang portion. It must be known that Glycyrrhizae Radix et Rhizoma in sweating formulas is indispensable. This formula may only be used when both pulse and symptoms are entirely at the exterior level. If the pulse is weak and faint with spontaneous sweating, it must not be used. Nowadays, people rigidly adhere to the idea that any condition within one or two days at the exterior level is suitable for sweating. If the Chi (Cun) position shows a wiry, rapid, deficient, or large pulse, indicating Yin deficiency with excessive fire, sweating will cause hyperactive Yang and heat jue (cold extremities) leading to death. If the Chi position shows a slow and weak pulse with cold feet, indicating Yang deficiency with Yin inclusion, sweating will cause loss of Yang and jue ni (rebellious cold) leading to death. Can one not be cautious?