《伤寒论》原治伤寒之书，而首论中风者，因中风亦可名为伤寒也（《难经》曰∶“伤寒有五；有中风，
有伤寒，有湿温，有热病，有温病”）。然究与真伤寒不同，盖中风病轻伤寒病重，为其重也，而治之者
必须用大有力之药，始能胜任，所谓大有力者，即《伤寒论》中之麻黄汤是也。今试论
麻黄汤证及麻黄汤制方之义，并详论用麻黄汤时通变化裁之法。
《伤寒论》原文∶太阳病，或已发热，或未发热，必恶寒，体痛，呕逆，脉阴阳俱紧者，名曰伤寒。
又原文∶太阳病头疼，发热，身疼，腰痛，骨节疼痛，恶风，无汗而喘者，麻黄汤主之。
脉象阴阳俱紧，实为伤寒之确征。然紧脉之状最难形容，惟深明其病理，自不难想象而得。脉生于心，
心一动而外输其血，周身之脉即一动，动则如波浪之有起伏，以理言之，凡脉之力大者，其起伏之势自应
愈大。至紧脉其跳动若有力而转若无所起伏，究其所以然之故，实因太阳为外卫之阳，因为寒所袭，逼之
内陷与脉相并，则脉得太阳蕴蓄之热，原当起伏有力以成响应之势，而寒气紧缩之力，又复逼压其脉道使不
能起伏，是以指下诊之似甚有力而竟直穿而过，且因其不得起伏，蓄极而有左右弹之势，此紧脉真象也。
至麻黄汤证，全体作疼痛者，以筋骨不禁寒气之紧缩也（铁条经严寒则缩短寒气紧缩之力可知）。其发
热者，身中之元阳为寒气闭塞不能宣散而增热也。其无汗恶风者，汗为寒闭内蕴之热原欲借汗透出，是
以恶风也。其作喘者，因手太阴肺经与卫共主皮毛，寒气由皮毛入肺，闭其肺中气管，是以不纳气而作喘。
然深究其作喘之由，犹不但此也，人之胸中亦太阳之部位也，其中间所积大气，原与
外表之卫气息息相通，然大气即宗气，《灵枢》谓∶“宗气积于胸
中，出于喉咙，以贯心脉而行呼吸。”夫大气既能以贯心脉，是营血之中亦大气所流通也，伤寒之证，其
营卫皆为外寒所束，则大气内郁必膨胀而上逆冲肺，此又喘之所由来也。
【麻黄汤方】麻黄三两，桂枝三两去皮，甘草一两炙，杏仁七十个去皮尖。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，去渣温服八合（一升十合），复取微似汗，不须啜
粥，余如桂枝法将息。
麻黄发汗力甚猛烈，先煮之去其浮沫，因其沫中含有发表之猛力，去之所以缓麻黄发表之性也。麻黄不
但善于发汗，且善利小便，外感之在太阳者，间有由经入府而留连不去者（凡太阳病多日不解者，皆是由
经入府），以麻黄发其汗，则外感之在经者可解，以麻黄利其小便，则外感之由经入府者，亦可分消也。且
麻黄又兼入手太阴能泻肺定喘，俾外感之由皮毛窜入肺者（肺主皮毛），亦清肃无遗。是以发太阳之汗者不但
麻黄，而仲景定此方时独取麻黄也。桂枝味辛性温，亦具有发表之力，而其所发表者，惟在肌肉之间，故
善托肌肉中之寒外出，且《神农本草经》谓其主上气咳逆吐吸（吸气甫入即吐出），是桂
枝不但能佐麻黄发表，兼能佐麻黄入肺定喘也。杏仁味苦性温，《神农本草经》亦谓其主咳逆上气，是亦能
佐麻黄定喘可知，而其苦降之性又善通小便，能佐麻黄以除太阳病之留连于府者，故又加之以为佐使也。至
于甘草之甘缓，能缓麻黄发汗之猛烈，兼能解杏仁之小毒，即以填补（甘草属土能填补）出汗后之汗腺空
虚也。药止四味，面面俱到，且又互相辅助，此诚非圣手莫办也。
附∶用麻黄汤之变通法
人之禀赋随天地之气化为转移，古今之气化或有不同，则今人与古人之禀赋，其强弱浓薄偏阴偏阳
之际不无差池，是以古方用于今日，正不妨因时制宜而为之变通加减也。
麻黄汤原用解其外寒，服后遍体汗出，恶寒既愈，有其病从此遂愈者，间有从此仍不愈，后浸发热
而转为阳明证者，其故何也？愚初为人诊病时，亦未解其故。后乃知服麻黄汤汗出后，其营卫内陷之热若还
表随汗消散，则其病即愈。若其热不复还表而内陷益深，其热必将日增，此即太阳转阳明之病也。悟得此理
后，再用麻黄汤时，必加知母数钱以解其内陷之热，主治伤寒无汗，服后未有不愈者矣（医方篇中有麻黄
加知母汤可参观）。大青龙汤治伤寒无汗烦躁，是胸中先有内热，无所发泄，遂郁而作烦躁，故于解表药中
加石膏以清内热。然麻黄与石膏并用，间有不汗之时。若用麻黄加知母汤，将知母重加数钱，其寒润之性入肺
中化合而为汗，随麻黄以达于外，而烦躁自除矣。
上所论者，麻黄汤原宜加知母矣。而间有不宜加者，此又不
得不斟酌也。间有其人阳分虚者，又当于麻黄汤中加补气之药以助之出汗。
一人年近四旬，身体素羸弱，于季冬得伤寒证，医者投以麻
黄汤汗无分毫，求为延医，其脉似紧而不任重按，遂于麻黄汤中加生黄 、天花粉各五钱，一剂得汗而愈。
一人亦年近四旬，初得外感，经医甫治愈，即出门作事，又重受外感，内外俱觉寒凉，头疼气息微喘，
周身微形寒战，诊其脉六部皆无，重按亦不见，愚不禁骇然，问其心中除觉寒凉外别无所苦，知犹可治，
不至有意外之虑，遂于麻黄汤原方中为加生黄 一两，服药后六脉皆出，周身得微汗，病遂愈。
一人，年过三旬，身形素羸弱，又喜吸鸦片。于冬令得伤寒证，因粗通医学，自服麻黄汤，分毫无汗。
求为诊视，脉甚微细，无紧象。遂即所用原方，为加生黄 五钱。服后得汗而愈。此二
证皆用麻黄汤是不宜加知母，宜加黄 者也。
尝治一少年，于季冬得伤寒证，其人阴分素亏，脉近六至，
且甚弦细，身冷恶寒，舌苔淡白。延医诊视，医者谓脉数而弱，伤寒虽在初得，恐不可用麻黄强发其汗。此时
愚应其近邻之聘，因邀愚至其家，与所延之医相商。愚曰∶“麻黄发汗之力虽猛，然少用则无妨，再辅以补正
之品，自能稳妥奏功矣。”遂为疏方∶麻黄钱半，桂枝尖一钱，杏仁、甘草各钱半，又为加生怀山药、
北沙参各六钱。嘱其煎汤服后，若至两点钟不出汗，宜服西药阿斯匹林二分许以助其出汗。后果如此服之，
周身得汗而愈矣。
曾治邻村李姓少年，得伤寒证已过旬日，表证未罢，时或恶寒，头犹微疼，舌苔犹白，心中微觉发热，
小便色黄，脉象浮弦，重按似有力，此热入太阳之腑（膀胱）也。投以麻黄汤，为加知母八钱，滑石六钱，
服后一汗而愈。
此证虽在太阳之表与腑，实已连阳明矣。故方中重用知母以清阳明之热，而仍用麻黄解其表，俾其余
热之未尽清者仍可由汗而消散，此所以一汗而愈也。至于《伤寒论》中载有其病重还太阳者，仍宜以麻黄汤
治之，而愚遇此证，若用麻黄汤时亦必重加知母也。
麻黄汤证有兼咽喉疼者，宜将方中桂枝减半，加天花粉六钱，射干三钱，若其咽喉疼而且肿者，麻黄
亦宜减半，去桂枝再加生蒲黄三钱以消其肿，然如此加减，凉药重而表药轻，若服后过点半钟不出汗时，亦
服西药阿斯匹林瓦许以助其汗；若服后汗仍不出时，宜阿斯匹林接续再服，以汗出为目标；若能遍体皆微
见汗，则咽喉之疼肿皆愈矣。
麻黄汤证，若遇其人素有肺劳病者，宜于原方中加生怀山药、天门冬各八钱。
麻黄汤证，若遇其人素有吐血病者，虽时已愈，仍宜去桂枝以防风二钱代之（吐血之证最忌桂枝），再
加生杭芍三钱（按古之一两约折为今之三钱，且将一次所煎之汤分作三剂，则一剂之中当有麻黄三钱），然又
宜因时、因地、因人细为斟酌，不必定以三钱为准也。如温和之时，汗易出少用麻黄即能出汗。严寒之
时，汗难出必多用麻黄始能出汗，此因时也。又如大江以南之人，其地气候温暖，人之生于其地者，其肌肤浅
薄，麻黄至一钱即可出汗，故南方所出医书有用麻黄不过一钱之语。至黄河南北，用麻黄约可以三钱为率。
至东三省人，因生长于严寒之地，其肌肤颇强浓，须于三钱之外再将麻黄加重始能得汗，此因地也。至于地
无论南北，时无论寒燠，凡其人之劳碌于风尘，与长居屋中者，其肌肤之浓薄强弱原自不同，即其汗之易
出不易出，或宜多用麻黄，或宜少用麻黄，原不一致，此因人也。用古人之方者，岂可胶柱鼓瑟哉！
《伤寒论》原本是治疗伤寒的书籍，但首先论述中风病，是因为中风也可以称为伤寒（《难经》说：“伤寒有五种；包括中风、伤寒、湿温、热病、温病”）。然而究其本质，它与真正的伤寒不同，大概中风病轻而伤寒病重，因为病情严重，所以治疗时必须使用药力强大的药物，才能胜任，所谓药力强大，就是指《伤寒论》中的麻黄汤。现在试着论述麻黄汤证及麻黄汤组方的意义，并详细论述使用麻黄汤时灵活变化的方法。
《伤寒论》原文：太阳病（太阳经受邪所致的病证），或者已经发热，或者尚未发热，必定恶寒（怕冷），身体疼痛，呕吐气逆，脉象寸关尺三部都紧的，名叫伤寒。
又原文：太阳病，头痛，发热，身体疼痛，腰痛，骨节疼痛，怕风，无汗且气喘的，用麻黄汤主治。
脉象寸关尺三部都紧，确实是伤寒的确切征象。然而紧脉的状态最难形容，只有深刻明白其病理，自然不难想象而得到。脉生于心，心脏一动就向外输送血液，全身的脉随之而动，跳动起来就像波浪一样有起伏，从道理上讲，凡是脉力大的，其起伏之势自然应该更大。至于紧脉，其跳动似乎有力却好像没有起伏，探究其所以然的原因，实在是因为太阳是体表的卫阳之气，被寒气侵袭，逼迫内陷与脉相并，此时脉得到太阳蕴蓄的热，原本应当起伏有力以形成响应的态势，而寒气紧缩的力量，又反过来压迫脉道使其不能起伏，所以在指下诊察时感觉很有力，但实际上直穿而过，并且因为它不能起伏，积蓄到极点就有左右弹击的趋势，这就是紧脉的真实景象。
至于麻黄汤证，全身作疼痛，是因为筋骨承受不住寒气的紧缩（铁条经过严寒就会缩短，可知寒气紧缩之力）。其发热的，是体内的元阳被寒气闭塞不能宣散而增加热度。其无汗怕风的，汗被寒邪闭塞，体内蕴积的热原想借出汗透出，所以怕风。其作喘的，是因为手太阴肺经与卫气共同主管皮毛，寒气由皮毛进入肺，闭塞了肺中的气管，所以不纳气而作喘。然而深入探究其作喘的原因，还不止于此，人的胸中也是太阳的部位，其中间积聚的大气，原本与外表的卫气息息相通，但大气即宗气，《灵枢》说：“宗气积聚在胸中，出于喉咙，贯通心脉而行呼吸。”既然大气能贯通心脉，那么营血之中也有大气的流通，伤寒的病证，其营卫都被外寒束缚，则大气在内郁结必然膨胀而上逆冲肺，这又是喘产生的由来。
【麻黄汤方】麻黄三两，桂枝三两去皮，甘草一两炙，杏仁七十个去皮尖。以上四味药用水九升，先煮麻黄减少二升，去掉上面的浮沫，加入其他药煮取二升半，去渣温服八合（一升等于十合），服药后覆盖衣被使身体微微似有汗出，不需要喝粥，其余调养方法如同桂枝汤法。
麻黄发汗力量非常猛烈，先煮它去掉浮沫，因为浮沫中含有发表（发散表邪）的猛力，去掉它以此来缓和麻黄发表的性质。麻黄不但善于发汗，而且善于利小便，外感病在太阳经的，偶尔有由经传入腑而留连不去的（凡是太阳病多日不解的，都是由经传入腑），用麻黄发其汗，则在经的外感病可以解除，用麻黄利其小便，则由经入腑的外感病，也可以分消化解。而且麻黄又兼入手太阴经能泻肺定喘，使得外感病由皮毛窜入肺的（肺主皮毛），也能清肃干净。所以发太阳之汗的不只是麻黄，而张仲景定此方时独取麻黄。桂枝味辛性温，也具有发表之力，但它所发表的，只在肌肉之间，所以善于将肌肉中的寒气托举外出，而且《神农本草经》说它主治上气咳逆吐吸（吸气刚入就吐出），是桂枝不但能辅助麻黄发表，还能辅助麻黄入肺定喘。杏仁味苦性温，《神农本草经》也说它主治咳逆上气，这也是它能辅助麻黄定喘的缘故，而它苦降的性质又善于通利小便，能辅助麻黄去除太阳病留连在腑的邪气，所以又加它作为佐使药。至于甘草的甘缓，能缓和麻黄发汗的猛烈，又能解杏仁的小毒，即用甘草属土能填补的特性来填补出汗后汗腺的空虚。药只有四味，面面俱到，而且互相辅助，这确实不是圣手不能办到的。
附：使用麻黄汤的变通方法
人的禀赋随着天地之气的变化而转移，古今的气化或许有不同，那么今人与古人的禀赋，在强弱浓薄偏阴偏阳方面不无差异，所以古方用于今日，正不妨因时制宜而进行变通加减。
麻黄汤原本用来解除外寒，服用后遍体汗出，恶寒既已痊愈，有的病人从此就痊愈了，偶尔有从此仍不愈，后来逐渐发热而转为阳明证（阳明病）的，这是什么原因呢？我初为人诊病时，也不明白其中的缘故。后来才知道服用麻黄汤汗出后，如果营卫内陷的热随汗消散，则病即愈。如果热不再还表而内陷更深，热必将日益增加，这就是太阳转阳明的病机。悟得这个道理后，再用麻黄汤时，一定加知母数钱以解除内陷的热，主治伤寒无汗，服用后没有不愈的（医方篇中有麻黄加知母汤可以参考）。大青龙汤治伤寒无汗烦躁，是胸中先有内热，无处发泄，于是郁结而作烦躁，所以在解表药中加入石膏以清内热。然而麻黄与石膏并用，有时不出汗。如果用麻黄加知母汤，将知母重加数钱，其寒润的性质入肺中化合而为汗，随麻黄到达体表，而烦躁自然消除。
上面所论述的，麻黄汤原本宜加知母的。而偶尔有不适宜加的，这又不得不斟酌。偶尔有阳气分虚弱的人，应当在麻黄汤中加入补气药以助其出汗。
有一人年近四十，身体素来羸弱，在深冬得了伤寒证，医生投以麻黄汤，汗出一分也没有，求我为他诊治，他的脉象似乎紧但不能重按，于是我在麻黄汤中加入生黄芪、天花粉各五钱，一剂药后得汗而愈。
另一人也年近四十，初次得外感，经医生刚刚治愈，就出门做事，又再次受外感，内外都觉寒凉，头疼气息微喘，周身轻微形寒战栗，诊其脉六部皆无，重按也看不见，我不禁骇然，问他心中除了觉寒凉外别无所苦，知道还可以治，不至于有意外之虑，于是在麻黄汤原方中加入生黄芪一两，服药后六脉皆出，周身得微汗，病遂愈。
第三人，年过三十，身形素来羸弱，又喜欢吸鸦片。在冬季得伤寒证，因为粗通医学，自服麻黄汤，分毫无汗。求我诊视，脉甚微细，无紧象。于是就用原方，加入生黄芪五钱。服后得汗而愈。这两个证候都是用麻黄汤不宜加知母，宜加黄芪的。
曾经治疗一个少年，在深冬得伤寒证，其人阴分素亏，脉接近六至（一息六至，为数脉），而且很弦细，身冷恶寒，舌苔淡白。请医生诊视，医生说脉数而弱，伤寒虽然刚得，恐怕不可用麻黄强发其汗。这时我应其邻居聘请，受邀到他家，与所延请的医生商量。我说：“麻黄发汗之力虽猛，但少用则无妨，再辅以补正之品，自然能稳妥奏效。”于是为他开方：麻黄钱半，桂枝尖一钱，杏仁、甘草各钱半，又加入生怀山药、北沙参各六钱。嘱咐他煎汤服后，如果到两小时不出汗，宜服西药阿斯匹林二分许以助其出汗。后果然如此服用，周身得汗而愈。
曾治疗邻村李姓少年，得伤寒证已过十天，表证未罢，时而恶寒，头犹微疼，舌苔犹白，心中微觉发热，小便色黄，脉象浮弦，重按似有力，这是热入太阳之腑（膀胱）也。投以麻黄汤，加入知母八钱，滑石六钱，服后一汗而愈。
这个证候虽然在太阳之表与腑，实则已连及阳明。所以方中重用知母以清阳明之热，而仍用麻黄解其表，使得其余热未尽清者仍可由汗而消散，这就是为什么一汗而愈的原因。至于《伤寒论》中记载有病重还太阳的，仍宜以麻黄汤治之，而我遇到此证，若用麻黄汤时也必重加知母。
麻黄汤证有兼咽喉疼的，宜将方中桂枝减半，加天花粉六钱，射干三钱，如果其咽喉疼而且肿的，麻黄也宜减半，去桂枝再加生蒲黄三钱以消其肿，然而如此加减，凉药重而表药轻，如果服后过半小时不出汗时，也服西药阿斯匹林瓦许（极少量）以助其汗；如果服后汗仍不出时，宜阿斯匹林接续再服，以汗出为目标；若能遍体皆微见汗，则咽喉之疼肿皆愈了。
麻黄汤证，如果遇到其人素有肺劳病（肺结核等慢性消耗性疾病）的，宜在原方中加入生怀山药、天门冬各八钱。
麻黄汤证，如果遇到其人素有吐血病的，虽然时候已愈，仍宜去桂枝以防风二钱代之（吐血之证最忌桂枝），再加生杭芍三钱（按古之一两约折为今之三钱，且将一次所煎之汤分作三剂，则一剂之中当有麻黄三钱），然而又宜因时、因地、因人细为斟酌，不必定以三钱为准也。如温和之时，汗易出少用麻黄即能出汗。严寒之时，汗难出必多用麻黄始能出汗，这是因时制宜。又如大江以南之人，其地气候温暖，人之生于其地者，其肌肤浅薄，麻黄至一钱即可出汗，故南方所出医书有用麻黄不过一钱之语。至黄河南北，用麻黄约可以三钱为率。至东三省人，因生长于严寒之地，其肌肤颇强浓，须于三钱之外再将麻黄加重始能得汗，这是因地制宜。至于地无论南北，时无论寒燠，凡其人之劳碌于风尘，与长居屋中者，其肌肤之浓薄强弱原自不同，即其汗之易出不易出，或宜多用麻黄，或宜少用麻黄，原不一致，这是因人制宜。用古人之方者，岂可胶柱鼓瑟（比喻拘泥成法，不知变通）哉！
*Shanghan Lun* (Treatise on Cold Damage) was originally a book for treating cold damage, yet it discusses wind-stroke first because wind-stroke can also be named cold damage (*Nan Jing* states: "There are five types of cold damage; including wind-stroke, cold damage, damp-warmth, heat disease, and warm disease"). However, upon investigation, it is different from true cold damage. Generally, wind-stroke is mild while cold damage is severe. Because of its severity, treatment must employ potent medicinal strength to be effective. What is meant by "potent" refers to *Mahuang Tang* (Ephedra Decoction) in *Shanghan Lun*. Now, let us discuss the syndrome of *Mahuang Tang* and the rationale behind its formulation, and elaborate on the methods of flexible modification when using *Mahuang Tang*.
Original text of *Shanghan Lun*: In Taiyang disease (disease pattern caused by pathogenic factors invading the Taiyang channel), whether fever has already appeared or not, there will inevitably be aversion to cold, body pain, vomiting and regurgitation, and a tight pulse at all positions (cun, guan, chi). This is named cold damage.
Another original text: In Taiyang disease, with headache, fever, body pain, lower back pain, joint pain, aversion to wind, absence of sweating, and wheezing, *Mahuang Tang* (Ephedra Decoction) should be used as the primary treatment.
A tight pulse at all positions is indeed a definitive sign of cold damage. However, the sensation of a tight pulse is hardest to describe; only by thoroughly understanding its pathology can one easily imagine and grasp it. The pulse originates from the Heart; when the Heart beats, it pumps blood outward, causing the entire body's vessels to pulsate. The movement resembles waves rising and falling. Logically, the greater the force of the pulse, the more pronounced its rising and falling momentum should be. As for the tight pulse, its beating seems forceful yet appears to lack fluctuation. Investigating the reason, it is actually because Taiyang represents the defensive Yang Qi of the exterior. When attacked by cold, this Qi is forced inward to merge with the vessels. The vessels receive the accumulated heat of Taiyang and should naturally rise and fall forcefully to create a responsive momentum. However, the constricting force of the cold simultaneously compresses the vessel pathways, preventing them from rising and falling. Therefore, upon palpation, the pulse feels very forceful but passes straight through without resistance. Furthermore, due to the inability to fluctuate, the accumulated energy creates a tendency to flicker left and right. This is the true image of a tight pulse.
Regarding the syndrome of *Mahuang Tang*, whole-body pain occurs because the muscles and bones cannot withstand the constriction of cold (as iron bars shorten in extreme cold, the constricting power of cold is evident). The fever arises because the primordial Yang Qi within the body is blocked by cold and cannot disperse, leading to increased heat. The absence of sweating and aversion to wind occur because sweat is closed by cold; the internally accumulated heat originally desires to escape via sweating, hence the aversion to wind. The wheezing occurs because the Lung Meridian of Hand-Taiyin and the Defensive Qi jointly govern the skin and hair. Cold enters the Lungs via the skin and hair, blocking the airways within the Lungs, resulting in an inability to inhale deeply and causing wheezing. However, investigating the cause of wheezing further, it is not limited to this. The chest is also a region of Taiyang. The Great Qi accumulated therein is intimately connected with the external Defensive Qi. But Great Qi is Zong Qi (Pectoral Qi); *Ling Shu* states: "Zong Qi accumulates in the chest, emerges from the throat, penetrates the heart vessels, and facilitates respiration." Since Great Qi can penetrate the heart vessels, it also circulates within the Ying Blood. In cold damage syndromes, both Ying and Wei are constrained by external cold, causing Great Qi to stagnate internally, expand, and rebel upward against the Lungs. This is another origin of wheezing.
[Mahuang Tang Formula] Ephedrae Herba (Mahuang, 麻黄) 3 liang, Cinnamomi Ramulus (Guizhi, 桂枝) 3 liang, peeled; Glycyrrhizae Radix et Rhizoma (Gancao, 甘草) 1 liang, honey-fried; Armeniacae Semen Amarum (Xingren, 杏仁) 70 seeds, peeled and removed of tips. These four ingredients are boiled in 9 sheng of water. First, boil Mahuang until reduced by 2 sheng, remove the foam on top, then add the remaining herbs and boil to obtain 2.5 sheng. Strain and take 8 ge warm (1 sheng equals 10 ge). After taking the medicine, cover with blankets to induce a slight, continuous sweating. There is no need to drink hot porridge. Rest and care instructions follow those for Guizhi Tang (Cinnamon Twig Decoction).
Mahuang has a very fierce sweating-inducing power. Boiling it first removes the floating foam because the foam contains the fierce power of releasing the exterior. Removing it serves to moderate the exterior-releasing nature of Mahuang. Mahuang is not only good at inducing sweating but also promotes urination. For exterior pathogens located in the Taiyang channel, occasionally they may enter the Fu organs and linger. (Generally, Taiyang diseases that do not resolve after many days involve the pathogen entering the Fu organs). Using Mahuang to induce sweating resolves the exterior pathogens in the channel; using Mahuang to promote urination helps dissipate pathogens that have entered the Fu organs from the channel. Moreover, Mahuang enters the Hand-Taiyin Lung Meridian to drain the Lungs and stop wheezing, ensuring that pathogens entering the Lungs via the skin and hair (which the Lungs govern) are thoroughly cleared. Thus, although not only Mahuang induces sweating in Taiyang, Zhang Zhongjing chose Mahuang exclusively for this formula. Guizhi is acrid and warm, possessing exterior-releasing power, but its action is confined to the muscle layer, making it excellent at pushing cold out from the muscles. Additionally, *Shen Nong Ben Cao Jing* states it treats upper Qi, cough, regurgitation, and inhalation-exhalation difficulties. Thus, Guizhi not only assists Mahuang in releasing the exterior but also assists in entering the Lungs to stop wheezing. Xingren is bitter and warm; *Shen Nong Ben Cao Jing* also states it treats cough and rebellious Qi, indicating its ability to assist Mahuang in stopping wheezing. Its bitter-descending nature also promotes urination, assisting Mahuang in removing lingering pathogens in the Fu organs of Taiyang, so it is added as an assistant herb. Gancao's sweet and moderating nature moderates the fierce sweating effect of Mahuang, detoxifies the slight toxicity of Xingren, and uses its earth-element property to fill the emptiness of sweat glands after sweating. With only four ingredients, the formula covers all aspects and mutually supports each other; truly, only a master could achieve this.
Appendix: Flexible Methods for Using Mahuang Tang
Human constitution shifts with the changes of Heaven and Earth's Qi. Since the Qi transformation of ancient times may differ from today, there are inevitably differences between the constitutions of ancients and modern people regarding strength, density, thinness, yin-yang bias, etc. Therefore, when applying ancient formulas today, it is appropriate to adapt them according to the times.
*Mahuang Tang* is originally used to release exterior cold. After ingestion, profuse sweating occurs, and if aversion to cold resolves, some patients recover completely. Occasionally, however, they do not recover immediately and later develop fever, transforming into a Yangming syndrome (Yangming disease). Why is this? When I first practiced medicine, I did not understand the reason. Later, I realized that after sweating following *Mahuang Tang*, if the heat trapped within the Ying and Wei returns to the surface and dissipates with sweat, the disease cures. If the heat does not return to the surface but sinks deeper, the heat will increase daily; this is the transition from Taiyang to Yangming. Having grasped this principle, when using *Mahuang Tang* now, I always add several qian of Anemarrhenae Rhizoma (Zhimu, 知母) to resolve the internally sinking heat. Treating cold damage with no sweating, this method has never failed to cure (see *Mahuang Jia Zhimu Tang* [Ephedra Plus Anemarrhena Decoction] in the Medical Formulas section for reference). *Da Qing Long Tang* (Major Green Dragon Decoction) treats cold damage with no sweating and irritability, indicating pre-existing internal heat in the chest that has no outlet, leading to depression and irritability. Therefore, Gypsum Fibrosum (Shigao, 石膏) is added to the exterior-releasing herbs to clear internal heat. However, combining Mahuang and Shigao sometimes fails to induce sweating. If using *Mahuang Jia Zhimu Tang* and adding a heavy dose of Zhimu, its cold-moistening nature combines in the Lungs to transform into sweat, reaching the exterior along with Mahuang, thereby eliminating irritability.
As discussed above, *Mahuang Tang* originally should include Zhimu. Yet occasionally, it is unsuitable, requiring careful consideration. Occasionally, patients with deficiency in the Yang aspect require the addition of Qi-tonifying herbs to *Mahuang Tang* to assist sweating.
One patient, nearly forty years old, was constitutionally frail. He contracted cold damage in late winter. The physician prescribed *Mahuang Tang*, but no sweat occurred. Seeking my consultation, his pulse seemed tight but could not withstand heavy pressure. I added Radix Astragali Preparata (Huangqi, 黄芪) and Trichosanthis Radix (Tianhuafen, 天花粉), each 5 qian, to the *Mahuang Tang*. One dose induced sweating and cured him.
Another patient, also nearly forty, had recently recovered from an initial exterior contraction. He went out to work and was re-exposed to exterior pathogens. He felt cold inside and out, had a slight headache, weak breathing, and mild chills. His pulse was imperceptible in all six positions, even under heavy pressure. I was startled but asked if he felt anything else besides coldness. Knowing he had no other distress, I deemed it treatable without unexpected risks. I added 1 liang of Huangqi to the original *Mahuang Tang*. After taking the medicine, all six pulses emerged, slight sweating occurred, and he recovered.
A third patient, over thirty years old, was constitutionally frail and addicted to opium. He contracted cold damage in winter. Being somewhat knowledgeable about medicine, he self-administered *Mahuang Tang* with no result. Upon examination, his pulse was very fine and thready, lacking a tight quality. I used the original formula, adding 5 qian of Huangqi. He sweated after taking it and recovered. These two cases illustrate situations where *Mahuang Tang* should not include Zhimu but should include Huangqi.
I once treated a young man who contracted cold damage in late winter. He had a chronic deficiency of Yin. His pulse was rapid (approaching six beats per breath), wiry, and fine. He had cold limbs, aversion to cold, and a pale white tongue coating. The attending physician noted the rapid and weak pulse and feared that despite early-stage cold damage, strong sweating with Mahuang was contraindicated. At that time, I was invited by his neighbor to consult. I said, "Although Mahuang's sweating power is fierce, using a small dose is harmless. Combined with herbs that tonify righteousness, it will surely succeed safely." I prescribed: Mahuang 1.5 qian, Guizhi tip 1 qian, Xingren and Gancao each 1.5 qian, plus Dioscoreae Hypoglaucae Rhizoma (Shanyao, 山药) and Glehniae Radix (Beishashen, 北沙参) each 6 qian. I instructed that if no sweat occurred within two hours, he should take approximately 2 fen of Aspirin to assist sweating. He followed this, sweated profusely, and recovered.
I once treated a young man surnamed Li from a neighboring village who had suffered from cold damage for ten days. The exterior syndrome had not resolved; he experienced intermittent aversion to cold, slight headache, white tongue coating, slight internal heat sensation, and yellow urine. His pulse was floating and wiry, seeming forceful under heavy pressure. This indicated heat entering the Fu organ of Taiyang (the Bladder). I prescribed *Mahuang Tang* with 8 qian of Zhimu and 6 qian of Talcum (Huashi, 滑石). One dose induced sweating and cured him.
Although this syndrome involved the exterior and Fu organ of Taiyang, it had essentially connected with Yangming. Therefore, a heavy dose of Zhimu was used to clear Yangming heat, while Mahuang was still used to release the exterior, allowing any remaining un-cleared heat to dissipate via sweat. This explains why one dose cured him. Regarding *Shanghan Lun* records of severe conditions returning to Taiyang, which should still be treated with *Mahuang Tang*, whenever I encounter such cases, I also heavily add Zhimu when using *Mahuang Tang*.
If the *Mahuang Tang* syndrome includes sore throat, reduce Guizhi by half in the formula, add 6 qian of Tianhuafen and 3 qian of Belamcandae Rhizoma (Shegan, 射干). If the throat is painful and swollen, reduce Mahuang by half, remove Guizhi, and add 3 qian of Poria Cum Radix (Shengpuhuang, 生蒲黄 - note: usually Poria is Fuling, Pu Huang is Pollen Typhae; here likely referring to Pollen Typhae for swelling) to reduce swelling. However, such modifications make cooling herbs heavy and exterior-releasing herbs light. If no sweat occurs after half an hour, take a small amount of Aspirin to assist sweating. If sweat still does not occur, continue administering Aspirin until sweating is achieved. If slight sweating covers the whole body, the throat pain and swelling will resolve.
If the *Mahuang Tang* syndrome involves a patient with a history of pulmonary consumption (lung tuberculosis/chronic wasting), add 8 qian of Shanyao and 8 qian of Asparagi Radix (Tianmendong, 天门冬) to the original formula.
If the *Mahuang Tang* syndrome involves a patient with a history of hemoptysis (coughing blood), even if cured, remove Guizhi and replace it with 2 qian of Saposhnikoviae Radix (Fangfeng, 防风) (Guizhi is strictly contraindicated in hemoptysis), and add 3 qian of Paeoniae Radix Alba (Baishao, 白芍). (Note: Ancient 1 liang approximates modern 3 qian. If dividing one decoction into three doses, each dose would contain approx. 3 qian of Mahuang). However, dosage must be carefully considered based on time, location, and individual characteristics, not rigidly fixed at 3 qian. During mild weather, sweat comes easily, so less Mahuang suffices. In severe cold, sweat is difficult to induce, requiring more Mahuang. This is adapting to the season. People south of the Yangtze River live in warm climates with thin skin; 1 qian of Mahuang suffices for sweating, hence southern medical texts often state Mahuang dosage should not exceed 1 qian. North and south of the Yellow River, 3 qian is the standard. People in Northeast China, growing up in severe cold with thick, robust skin, require more than 3 qian to induce sweating. This is adapting to geography. Regardless of north or south, or cold or warm seasons, individuals working outdoors versus those staying indoors have different skin thickness and strength, affecting ease of sweating. Dosage of Mahuang varies accordingly. This is adapting to the person. How can one use ancient formulas without flexibility?