凡病有名有症，有机有情，如中风、伤寒、温暑、湿痉等类，此为名也。外有头痛、身痛、腰痛，内有喘咳、
烦渴、吐利、腹满，此为症也。其间在表在里，有汗无汗，脉浮脉沉，有力无力，是其机也。此时恶寒恶热，苦
满喜呕，能食不欲食，欲卧不得卧，或饮水数升，或漱水不欲咽，皆病情也。因名立方者，粗工也；据症定方者，
中工也；于症中审病机察病情者，良工也。仲景制方，不拘病之命名，惟求症之切当，知其机得其情，凡中风伤
寒杂病，宜主某方，随手拈来，无不活法，此谓医不执方也。今谈仲景方者，皆曰桂枝汤治中风，不治伤寒，麻
黄汤治伤寒，不治中风。不审仲景此方主何等症，又不审仲景何症用何等药，只在中风、伤寒二症中较量，青龙、
白虎命名上敷衍，将仲景活方活法，为死方死法矣。
仲景立方精而不杂，其中以六方为主，诸方从而加减焉。凡汗剂皆本桂枝，吐剂皆本栀豉，攻剂皆本承气，
和剂皆本柴胡，寒剂皆本泻心，温剂皆本四逆。溷而数之，为一百十三方者，未之审也。
六经各有主治之方，而他经有互相通用之妙。如麻、桂二汤，为太阳营卫设，而阳明之病在营卫者亦用之。
真武汤为少阴水气设，而太阳之汗后亡阳者亦用之。四逆汤为太阴下利清谷设，太阳之脉反沉者宜之。五苓散为
太阳消渴水逆设，阳明之饮水多者亦宜之。猪苓汤为少阴下利设，阳明病小便不利者亦宜之。抵当汤为太阳瘀血
在里设，阳明之蓄血亦用之。瓜蒂散为阳明胸中痞硬设，少阴之温温欲吐者亦用之。合是症便用是方，方各有经，
而用可不拘，是仲景法也。仲景立方，只有表里寒热虚实之不同，并无伤寒中风杂症之分别，且风寒有两汤迭用
之妙，表里有二方更换之奇。或以全方取胜，或以加减奏功。后人论方不论症，故反以仲景方为难用耳。桂枝汗
剂中第一品也，麻黄之性直透皮毛，生姜之性横散肌肉。故桂枝佐麻黄，则开玄府而逐卫分之邪，令无汗者有汗
而解，故曰发汗；桂枝率生姜，则开腠理而驱营分之邪，令有汗者复汗而解，故曰解肌。解肌者解肌肉之邪也，
正在营分，何立三纲者反立麻黄主营、桂枝主卫耶？麻黄不言解肌，而肌未尝不解；桂枝之解肌，正所以发汗。
要知麻黄桂枝二汤，是发汗分深浅之法，不得以发汗独归麻黄，不得以解肌与发汗对讲。前人论方不论药，只以
二方为谈柄，而置之不用也。
凡风寒中人，不在营卫，即入腠理。仲景制桂枝汤调和营卫，制柴胡汤调和腠理。观六经症，仲景独出桂枝
症、柴胡症之称，见二方任重，不可拘于经也。惟太阳统诸阳之气，六经表症，咸属于太阳，故柴胡汤得与桂枝
汤对待于太阳之部。桂枝本为太阳风寒设，凡六经初感之邪，未离营卫者悉宜之；柴胡本为少阳半表设，凡三阳
半表之邪，逗留腠理者悉宜之。仲景最重二方，所以自为桂枝症注释，又为小柴胡注释。桂枝有疑似症，柴胡亦
有疑似症。桂枝有坏病，柴胡亦有坏病。桂枝症罢，桂枝不中与矣，而随症治法，仍不离桂枝方加减；柴胡症罢，
柴胡不中与矣，而设法救逆，仍不出柴胡方加减。
麻黄症热全在表。桂枝之自汗，大青龙之烦躁，皆兼里热。仲景于表剂中，便用寒药以清里。自汗是烦之兆，
躁是烦之征。汗出则烦得外泄，故不躁，宜用微寒酸苦之味以和之；汗不出则烦不得泄，故躁，
宜用大寒坚重之品以清之。夫芍药、石膏是里药入表剂，今人不审表中有里，因生疑畏，当用不用，至热并阳明，
而斑黄狂乱发矣。是不任大青龙之过也。仲景于太阳经中用石膏以清胃火，是预保阳明之先着；加姜、枣以培中，
又虑夫转属太阴矣。
小青龙、柴胡，俱是两解表里之剂，小青龙重在里症，小柴胡重在表症。故小青龙加减，麻黄可去；小柴胡
加减，柴胡独存。盖小青龙重在半里之水，小柴胡重在半表之热也。小青龙治伤寒未解之水气，故用温剂，汗而
发之；十枣汤治中风已解之水气，故用寒剂，引而竭之。此寒水、风水之异治也。小青龙之水，动而不居；五苓
散之水，留而不行；十枣汤之水，纵横不羁；大陷胸之水，痞硬坚满；真武汤之水，四肢沉重。水气为患不同，
所以治法各异。
林亿云∶“泻心本名理中黄连人参汤，盖泻心疗痞，正是理中处。”当知仲景用理中，有寒热两法，一以扶
阳，一以益阴也。邪在营卫之间，惟汗是其出路，故立麻黄、桂枝二方。邪在胸腹之间，惟吐是其出路，故立瓜
蒂、栀豉二方。瓜蒂散主胸中痞硬，治在上焦；栀豉汤主腹满而喘，治兼中焦。犹麻黄之主皮肤，桂枝之主肌肉。
瓜蒂散峻剂也，犹麻黄之不可轻用；栀豉汤轻剂也，犹桂枝汤之可更用而无妨。故太阳表剂，多从桂枝加减；阳
明表剂，多从栀豉加减。阳明用栀豉，犹太阳用桂枝，既可用之以去邪，即可用之以救逆。今人但知汗为解表，
不知吐亦为解表，知吐中使能发散之说，不知所以当吐之义。故于仲景大法中，取其汗下遗其吐法耳。
少阳为枢，不全在里，不全在表。仲景本意重里，而柴胡所主又在半里，故必见半表病情，乃得从柴胡加减。
如悉入在里，则柴胡非其任矣，故柴胡称解表之方。小柴胡虽治在半表，实以理三焦之气，所以称枢机之剂。如
胸满胸中烦，心烦心下悸，咳渴喜呕，是上焦无开发之机也；腹满胁下痞硬，是中焦废转运之机也；小便不利，
是下焦失决渎之任也。皆因邪气与正气相搏而然，用人参扶三焦之正气，壮其枢耳。
少阴病二三日，心中烦不得卧者，病本在心，法当滋离中之真火，随其势之润下，故君黄连之苦寒以泄之。
四五日小便不利，下脓血者，病本在肾，法当升坎中之少火，顺其性之炎上，故佐干姜之苦温以发之。此伏明之
火，与升明之火不同。少阴心烦欲寐，五六日，欲吐不
吐，自利而渴，小便色白者，是下焦虚寒，不能制水，宜真武汤，以温下焦之肾水。下利六七日，咳而呕渴，心
烦不眠，是上焦虚热，水津不布，宜猪苓汤，以通上焦之津液。
四逆为太阴主方，而诸经可以互用。在太阴本经，固本以逐邪也；用于少阴，温土以制水也；用于厥阴，和
土以生木也；用于太阳，益火以扶元阳也。惟阳明胃实、少阳相火，非所宜耳。
少阴病四五日，腹痛小便不利，下利不止。若四肢沉重疼痛者，为下焦水郁，用真武汤，是引火归元法；若
便脓血者，为下焦火郁，用桃花汤，是升阳散火法。此因坎中阳虚，不得以小便不利作热治。
小柴胡为少阳主方，乌梅为厥阴主方。二方虽不同，而寒温互用、攻补兼施之法相合者，以脏腑相连、经络
相贯、风木合气、同司相火故也。其中皆用人参，补中益气以固本逐邪，而他味俱不相袭者，因阴阳异位。阳宜
升发，故主以柴胡；阴宜收降，故主以乌梅。阳主热，故重用寒凉；阴主寒，故重用辛热。阳以动为用，故汤以
荡之，其症变幻不常，故柴胡有加减法；阴以静为体，故丸以缓之，其症有定局，故乌梅无加减法也。
厥阴下利，用白头翁汤，升阳散火，是火郁发之也。制乌梅丸以收火，是曲直作酸之义。佐苦寒以和阴，主
温补以存阳，是肝家调气之法也。其治厥利与久利，故半兼温补。白头翁汤主中风热利与下重，故专于凉散。
按∶发表攻里，乃御邪之长技。盖表症皆因风寒，如表药用寒凉，则表热未退而中寒又起。所以表药必用桂
枝，发表不远热也，然此为太阳表热言耳。如阳明少阳之发热，则当用柴、芩、栀、豉之类主之。里症皆因郁热，
下药不用苦寒，则瘀热不除，而邪无出路。所以攻剂必用大黄，攻里不远寒也，然此谓阳明胃热言耳。如恶寒痞
硬，阳虚阴结者，又当以姜、附、巴豆之类兼之矣。
麻黄、桂枝，太阳阳明表之表药；瓜蒂、栀豉，阳明里之表药；小柴胡，少阳半表之表药。太阴表药桂枝汤，
少阴表药麻黄附子细辛汤，厥阴表药当归四逆汤。六经之用表药，为六经风寒之出路也。
手足厥逆之症，有寒热表里之各异。四逆散解少阴之里热，当归四逆汤解厥阴之表寒，通脉四逆汤挽少阴真
阳之将亡，茯苓四逆汤留太阴真阴之欲脱。四方更有各经轻重浅深之别也。
膀胱主水，为太阳之里，十枣、五苓，为太阳水道之下药；胃腑主谷，为阳明之里，三承气为阳明谷道之下
药；胆腑主气；为少阳之里，大柴胡为少阳气分之下药。此三阳之下药，三阳实邪之出路也。大肠小肠，皆属于
胃，胃家实则二肠俱实矣。若三分之，则调胃承气胃家之下药，小承气小肠之下药，大承气大肠之下药。戊为燥
土，庚为燥金，故加芒硝以润其燥也。桂枝加大黄，太阳转属阳明之下药；桂枝加芍药，太阳转属太阴之下药。
凡下剂兼表药，以未离于表故也。柴胡加芒硝，少阳转属阳明之下药。大柴胡下少阳无形之邪，柴胡加芒硝下少
阳有形之邪也。桂枝加芍药下太阴无形之邪，三物白散下太阴有形之邪也。四逆散下少阴厥阴无形之邪，承气汤
下诸经有形之邪也。其间有轻重之分；下剂之轻者，只用气分药；下剂之重者，兼用血分药。酸苦涌泄，下剂之
轻，故芍药、枳实为轻；咸苦涌泄，下剂之重，故大黄、芒硝为重。
仲景用攻下二字，不专指大便。凡与桂枝汤欲攻其表，此指发汗言；表解者乃可攻之，指利水言；有热属脏
者攻之，指清火言也。寒湿在里不可下，指利水言；以有热故也，当以汤下之，指清火言也。
仲景下剂，只重在汤，故曰医以丸药下之，非其治也。观陷胸、抵当二丸，仍用水制，是丸复其汤，重两许，
连滓服，则势力更猛于汤、散剂矣。当知仲景方以铢、两、分计者，非外感方；丸如桐子大，每服十丸者，不是
治外感法。
仲景制方，随方立禁，使人受其功不蹈其弊也。如用发表药，一服汗者停后服。若脉浮紧发热汗不出者，不
可与桂枝；若脉微弱汗出恶风者，不可服大青龙汤；脉浮发热无汗，表不解者，不可与白虎；诸亡血虚家，不可
用瓜蒂；病患旧微溏者，不可与栀子；阳明病汗出多者，不可与猪苓；外未解，其热不潮者，未可与承气；呕家
不可与建中。皆仲景慎重出之者也。仲景加减有深意。如腹中痛者，少阳加芍药，少阴加附子，太阴加人参。若
心下悸者，少阴加桂枝，少阳加茯苓。若渴者，少阳加栝蒌根、人参，太阴加白术。加减中分阴阳表里如此。故
细审仲景方，知随症立方之妙；理会仲景加减法，知其用药取舍之精。
小青龙设或然五症，加减法内即备五方。小柴胡设或然七症，即具加减七方。要知仲景有主治之方，如麻、
桂等方是也；有方外之方，如桂枝汤加附子加大黄辈是也；有方内之方，如青龙、真武之有加减
法是也。仲景书法中有法，方外有方，何得以三百九十七法、一百一十三方拘之耶？
昔岐伯创七方以制病，仲景更穷其病之变幻，而尽其精微。如发表攻里，乃逐邪大法，而发表攻里之方，各
有大小，如青龙、柴胡、陷胸、承气是也。夫发表既有麻黄、桂枝方矣，然有里邪夹表而见者，治表不及里，非
法也。而里邪又有夹寒夹热之不同，故制小青龙以治表热里寒，制大青龙以治表寒里热，是表中便兼解里也，不
必如坏病之先里后表、先表后里之再计也。然大、小青龙，即麻、桂二方之变，只足以解营卫之表，不足以驱腠
理之邪。且邪留腠理之间，半表之往来寒热虽同，而半里又有夹虚夹实之悬殊。因制小柴胡而防半里之虚，大柴
胡以除半里之实，是表中便兼和里也，不必如后人之先攻后补、先补后攻之斟酌也。攻里既有调胃承气矣，然里
邪在上焦者有夹水夹痰之异，在中焦者有初硬后溏、燥屎定硬之分，非调胃所能平也。因制小陷胸以清胸膈之痰，
大陷胸以下胸膈之水，小承气以试胃家之矢气，大承气以攻肠胃之燥屎，方有分寸，邪气去而元气无伤，不致有
顾此遗彼、太过不及之患也。按发表攻里之方，各有缓急之法。如麻黄、大承气汗下之急剂也，而桂枝则发表之缓
剂。其用桂枝诸法，是缓汗中更有轻重矣。小承气下之缓剂也，曰少与之令小安，曰微和胃气，曰不转矢气者勿
更与之。其调胃承气下之尤缓者也，曰少少温服之，且不用气分药，更加甘草。是缓下中亦有差别矣。若夫奇偶
之法，诸方既已备见，而更有麻桂各半之偶，有桂枝二麻黄一之奇，是奇偶中之各有浅深也。服桂枝汤已，须更
啜热粥，为复方矣，而更有取小柴胡一升加芒硝之复，是复中又分汗下二法矣。若白散之用复方更异，不利，进
热粥一杯，利不止，进冷粥一杯，是一粥中又寓热泻冷补之二法也。
病有虚热相关，寒热夹杂，有时药力所不能到者，仲景或针或灸以治之。自后世针、药分为两途，刺者勿药，
药者勿刺，岂知古人刺、药相须之理。按岐伯治风厥，表里刺之，饮之以汤。故仲景治太阳中风，服桂枝汤反烦
凡是疾病都有名称和症状，有机理和病情。例如中风、伤寒、温病、暑病、湿病、痉病等类别，这是疾病的“名”。外在表现有头痛、身痛、腰痛，内在表现有气喘咳嗽、心烦口渴、呕吐腹泻、腹部胀满，这是疾病的“症”。其中病位在表或在里，有汗或无汗，脉象浮或沉，脉力有力或无力，这是疾病的“机”（关键机理）。此时患者恶寒或恶热，胸胁苦满且喜欢呕吐，能进食或不想进食，想睡觉却睡不着，或者喝几升水，或者含水漱口却不咽下，这些都是疾病的“情”（具体表现状态）。根据名称来制定方剂的，是粗劣的医生；根据症状来确定方剂的，是中等的医生；在症状中审察病机并观察病情的，是优秀的医生。张仲景制定方剂，不拘泥于疾病的命名，只追求症状的准确对应，掌握了病机并了解了病情，凡是中风、伤寒及杂病，适宜用哪个方子，随手拿来，没有不是灵活变化的，这叫做医生不固执于固定的方剂。现在谈论仲景方的人，都说桂枝汤治疗中风，不治疗伤寒，麻黄汤治疗伤寒，不治疗中风。不审察仲景这个方子主治什么症状，也不审察仲景针对什么症状使用什么药物，仅仅在中风和伤寒这两个症状中进行比较，在青龙、白虎这些命名上敷衍了事，把仲景灵活的方剂和治法变成了死板的方剂和治法。
仲景创立方剂精妙而不杂乱，其中以六个方子为主干，其他方子都由此加减而来。凡是发汗的方剂都以桂枝汤为本，催吐的方剂都以栀子豉汤为本，攻下的方剂都以承气汤为本，和解的方剂都以柴胡汤为本，清热的方剂都以泻心汤为本，温里的方剂都以四逆汤为本。混杂在一起数起来有一百一十三方的，是没有经过仔细审察的缘故。
六经各有主治的方剂，而其他经也有互相通用的奥妙。例如麻黄汤、桂枝汤，是为太阳经营卫不和设立的，但阳明经病在营卫阶段的也使用它们。真武汤是为少阴经水气病设立的，但太阳经发汗后亡阳的也使用它。四逆汤是为太阴经下利清谷设立的，太阳经脉象反而沉的适宜使用。五苓散是为太阳经消渴、水逆设立的，阳明经饮水多的也适宜使用。猪苓汤是为少阴经下利设立的，阳明经小便不利的也适宜使用。抵当汤是为太阳经瘀血在里设立的，阳明经蓄血的也使用它。瓜蒂散是为阳明经胸中痞硬设立的，少阴经温温欲吐的也使用它。符合这个症状就用这个方子，方剂各有归属的经络，但运用可以不拘泥，这就是仲景的法度。仲景创立方剂，只有表里、寒热、虚实的不同，并没有伤寒、中风、杂病的分别，而且风寒有两方交替使用的奥妙，表里有两方更换的奇特。有的用全方取胜，有的通过加减奏效。后人论方不论症，所以反而觉得仲景的方子难用。桂枝汤是发汗剂中的上品，麻黄的药性直透皮毛，生姜的药性横散肌肉。所以桂枝辅助麻黄，就能打开玄府（汗孔）而驱逐卫分的邪气，让无汗的人出汗而解表，所以叫发汗；桂枝率领生姜，就能打开腠理而驱除营分的邪气，让有汗的人再次出汗而解表，所以叫解肌。解肌就是解除肌肉层面的邪气，病位正在营分，为什么立三纲学说的人反而说麻黄主营、桂枝主卫呢？麻黄汤不说解肌，但肌肉之邪未尝不解；桂枝汤的解肌，正是为了发汗。要知道麻黄汤和桂枝汤，是发汗分为深浅的方法，不能把发汗单独归给麻黄，也不能把解肌与发汗对立起来讨论。前人论方不论药，只把这两个方子当作谈资，而放置不用。
凡是风寒侵入人体，不在营卫，就进入腠理。仲景制定桂枝汤以调和营卫，制定柴胡汤以调和腠理。观察六经症状，仲景唯独提出桂枝症、柴胡症的称呼，可见这两个方子责任重大，不可拘泥于某一经。只有太阳经统摄诸阳之气，六经的表证都归属于太阳，所以柴胡汤得以与桂枝汤在太阳经部相对待。桂枝汤本是为太阳经风寒设立的，凡是六经初感的外邪，未离开营卫的都适宜使用；柴胡汤本是为少阳经半表半里设立的，凡是三阳经半表半里的邪气，停留在腠理的都适宜使用。仲景最重视这两个方子，所以专门为桂枝症作注释，又为小柴胡汤作注释。桂枝汤有疑似的症状，柴胡汤也有疑似的症状。桂枝汤证有坏病，柴胡汤证也有坏病。桂枝汤证消失后，桂枝汤就不能再用了，但随症治法，仍然不离桂枝汤的加减；柴胡汤证消失后，柴胡汤就不能再用了，但设法救逆，仍然不出柴胡汤的加减范围。
麻黄汤证的发热完全在表。桂枝汤证的自汗，大青龙汤证的烦躁，都兼有里热。仲景在表剂中，便使用寒凉药物以清里热。自汗是心烦的先兆，躁动是心烦的表现。出汗则烦热能向外宣泄，所以不躁动，适宜用微寒酸苦的药物来调和；不出汗则烦热不得宣泄，所以躁动，适宜用大寒重坠的药物来清泄。芍药、石膏是入里的药放入表剂中，现在的人不审察表中有里证，因此产生疑虑畏惧，该用不用，导致热邪并入阳明经，出现发斑、发黄、狂乱等症状。这是不能胜任使用大青龙汤的过错。仲景在太阳经中使用石膏以清胃火，是预先保护阳明经的先着；加入姜、枣以培补中气，又是担心病邪转属太阴经了。
小青龙汤、柴胡汤，都是表里双解的方剂，小青龙汤重在里证，小柴胡汤重在表证。所以小青龙汤加减时，麻黄可以去掉；小柴胡汤加减时，唯独柴胡保留。因为小青龙汤重在半里的水饮，小柴胡汤重在半表的热邪。小青龙汤治疗伤寒未解的水气，所以用温剂，通过发汗来发散；十枣汤治疗中风已解的水气，所以用寒剂，通过引导排泄来竭尽水邪。这是寒水、风水不同的治疗方法。小青龙汤所治之水，流动而不居停；五苓散所治之水，停留而不运行；十枣汤所治之水，纵横不受约束；大陷胸汤所治之水，痞硬坚满；真武汤所治之水，四肢沉重。水气为患各不相同，所以治疗方法各异。
林亿说：“泻心汤本名理中黄连人参汤，大概是因为泻心汤治疗痞证，正是理中汤的作用所在。”应当知道仲景使用理中汤，有寒热两种方法，一种是为了扶助阳气，一种是为了益养阴液。邪气在营卫之间，只有发汗是出路，所以设立麻黄汤、桂枝汤两个方子。邪气在胸腹之间，只有催吐是出路，所以设立瓜蒂散、栀子豉汤两个方子。瓜蒂散主治胸中痞硬，治疗在上焦的病；栀子豉汤主治腹部胀满且气喘，治疗兼有中焦的病。就像麻黄汤主治皮肤，桂枝汤主治肌肉一样。瓜蒂散是峻猛之剂，就像麻黄汤不可轻率使用；栀子豉汤是轻扬之剂，就像桂枝汤可以反复使用而无妨。所以太阳经的表剂，多从桂枝汤加减；阳明经的表剂，多从栀子豉汤加减。阳明经使用栀子豉汤，就像太阳经使用桂枝汤，既然可以用它来祛除邪气，就可以用它来救逆。现在的人只知道发汗是解表，不知道催吐也是解表，只知道吐法中有发散的说法，不知道之所以要催吐的意义。所以在仲景的大法中，只取发汗和攻下，遗漏了催吐法。
少阳经为枢机，不全在里，不全在表。仲景的本意重视里证，而柴胡汤所主的又在半里，所以必须见到半表的病情，才能从柴胡汤加减。如果全部陷入在里，那么柴胡汤就不是它的职责了，所以柴胡汤被称为解表的方剂。小柴胡汤虽然治疗在半表，实际上是以调理三焦之气为主，所以称为枢机之剂。如胸满、胸中烦，心烦、心下悸，咳嗽、口渴、喜欢呕吐，这是上焦没有开发之机；腹部胀满、胁下痞硬，是中焦废弛转运之机；小便不利，是下焦失去决渎的职责。都是因为邪气与正气相搏结所致，用人参扶助三焦的正气，壮大其枢机功能。
少阴病二三天，心中烦闷不能入睡的，病根在心，法当滋助离中之真火，顺应其势润下，所以以黄连的苦寒为君药以清泄之。四五天后小便不利，排出脓血的，病根在肾，法当升发坎中之少火，顺应其性炎上，所以以干姜的苦温为佐药以发散之。这是伏明之火与升明之火的不同。少阴病心烦嗜睡，五六天，想吐吐不出来，自行腹泻且口渴，小便颜色白的，是下焦虚寒，不能制约水液，适宜用真武汤，以温煦下焦的肾水。腹泻六七天，咳嗽且呕吐口渴，心烦失眠的，是上焦虚热，水津不能布散，适宜用猪苓汤，以通调上焦的津液。
四逆汤是太阴经的主方，但各经可以互用。在太阴本经，是固护根本以驱逐邪气；用于少阴经，是温脾土以制约水邪；用于厥阴经，是调和脾土以生肝木；用于太阳经，是益火以扶持元阳。只有阳明经胃实、少阳经相火，是不适宜的。
少阴病四五天，腹痛小便不利，腹泻不止。如果四肢沉重疼痛的，是下焦水气郁滞，用真武汤，这是引火归元的方法；如果大便脓血的，是下焦火气郁滞，用桃花汤，这是升阳散火的方法。这是因为坎中阳气虚弱，不能把小便不利当作热证来治疗。
小柴胡汤是少阳经的主方，乌梅丸是厥阴经的主方。这两个方子虽然不同，但寒温互用、攻补兼施的方法相合，是因为脏腑相连、经络相通、风木合气、同司相火的缘故。其中都使用人参，补益中气以固本逐邪，而其他药物都不相互袭用的，是因为阴阳位置不同。阳气宜升发，所以以柴胡为主；阴气宜收降，所以以乌梅为主。阳主热，所以重用寒凉药；阴主寒，所以重用辛热药。阳以动为用，所以用汤剂来荡涤，其症状变幻无常，所以柴胡汤有加减法；阴以静为体，所以用丸剂来缓和，其症状有定局，所以乌梅丸没有加减法。
厥阴经下利，使用白头翁汤，升阳散火，这是火郁发之的方法。制作乌梅丸以收敛火势，这是曲直作酸的含义。辅以苦寒药以调和阴气，主用温补药以保存阳气，这是肝脏调理气机的方法。因为它治疗厥逆下利和久利，所以一半兼用温补。白头翁汤主治中风热利和里急后重，所以专于凉散。
按语：发表攻里，是抵御邪气的长技。大概表证都是因为风寒，如果表药用寒凉药，那么表热未退而中寒又起。所以表药必须用桂枝，发表不远热，但这只是针对太阳经表热而言。如果是阳明、少阳的发热，则应当用柴胡、黄芩、栀子、豆豉之类的药物为主。里证都是因为郁热，下药不用苦寒药，那么瘀热不除，邪气没有出路。所以攻下剂必须用大黄，攻里不远寒，但这只是针对阳明经胃热而言。如果是恶寒痞硬，阳虚阴结的情况，又应当用干姜、附子、巴豆之类的药物兼用。
麻黄汤、桂枝汤，是太阳、阳明经表证的表药；瓜蒂散、栀子豉汤，是阳明经里证的表药；小柴胡汤，是少阳经半表半里的表药。太阴经的表药是桂枝汤，少阴经的表药是麻黄附子细辛汤，厥阴经的表药是当归四逆汤。六经使用表药，是为了给六经的风寒提供出路。
手足厥逆的症状，有寒热表里的不同。四逆散解少阴经的里热，当归四逆汤解厥阴经的表寒，通脉四逆汤挽回少阴经真阳的将亡，茯苓四逆汤留住太阴经真阴的欲脱。这四个方子更有各经轻重浅深的区别。
膀胱主水，是太阳经的里，十枣汤、五苓散，是太阳经水道之下的下药；胃腑主谷，是阳明经的里，三个承气汤是阳明经谷道之下的下药；胆腑主气，是少阳经的里，大柴胡汤是少阳经气分之下的下药。这三个阳经的下药，是三阳经实邪的出路。大肠小肠，都归属于胃，胃家实则二肠俱实。如果三分开来，那么调胃承气汤是胃家之下的下药，小承气汤是小肠之下的下药，大承气汤是大肠之下的下药。戊为燥土，庚为燥金，所以加芒硝以润其燥。桂枝加大黄汤，是太阳经转属阳明经之下的下药；桂枝加芍药汤，是太阳经转属太阴经之下的下药。
凡是下剂兼用表药，是因为病邪未完全离开表的原因。柴胡加芒硝汤，是少阳经转属阳明经之下的下药。大柴胡汤下少阳经无形的邪气，柴胡加芒硝汤下少阳经有形的邪气。桂枝加芍药汤下太阴经无形的邪气，三物白散下太阴经有形的邪气。四逆散下少阴、厥阴经无形的邪气，承气汤下各经有形的邪气。其中有轻重的区分；下剂中轻的，只用气分药；下剂中重的，兼用血分药。酸苦涌泄，是下剂之轻，所以芍药、枳实为轻；咸苦涌泄，是下剂之重，所以大黄、芒硝为重。
仲景使用“攻下”二字，不专指大便。凡是给桂枝汤想要攻其表，这是指发汗；表解之后才可以攻之，这是指利水；有热属于脏者攻之，这是指清火。寒湿在里不可下，这是指利水；因为有热，应当用汤药下之，这是指清火。
仲景的下剂，只重在汤剂，所以说医生用丸药攻下，不是正确的治法。看陷胸汤、抵当汤两个丸剂，仍然是用水煮制，是丸剂恢复成汤剂的效果，重量一两许，连同药渣一起服用，那么势力比汤剂、散剂更猛烈。应当知道仲景的方子以铢、两、分计算的，不是外感方；丸药像梧桐子大，每次服用十丸的，不是治疗外感的方法。
仲景制定方剂，随方设立禁忌，使人接受其功效而不陷入其弊端。例如使用发表药，服一次出汗的就停止后服。如果脉浮紧、发热、无汗的，不可以给桂枝汤；如果脉微弱、出汗、恶风的，不可服用大青龙汤；脉浮发热、无汗，表证未解的，不可给白虎汤；所有亡血、虚家，不可用瓜蒂散；病人旧有轻微溏泄的，不可给栀子豉汤；阳明病出汗多的，不可给猪苓汤；表证未解，热势不潮的，不可给承气汤；呕吐家常不可给建中汤。这都是仲景慎重提出的。仲景的加减有深意。如腹中痛的，少阳经加芍药，少阴经加附子，太阴经加人参。如果心下悸动的，少阴经加桂枝，少阳经加茯苓。如果口渴的，少阳经加栝蒌根、人参，太阴经加白术。加减中区分阴阳表里如此。所以仔细审察仲景的方子，就知道随症立方之妙；理会仲景的加减法，就知道他用药取舍的精妙。
小青龙汤设有五种或然症，加减法内即具备五个方子。小柴胡汤设有七种或然症，即具备七个加减方。要知道仲景有主治的方子，如麻黄汤、桂枝汤等方是；有方外之方，如桂枝汤加附子、加大黄之类是；有方内之方，如青龙汤、真武汤有加减法是。仲景书法中有法，方外有方，怎么能用三百九十七法、一百一十三方来拘束呢？
从前岐伯创立七方以治病，仲景更进一步穷究病证的变幻，而尽其精微。如发表攻里，是驱逐邪气的大法，而发表攻里的方子，各有大小，如青龙汤、柴胡汤、陷胸汤、承气汤是。发表既有麻黄汤、桂枝汤了，然而有里邪夹表而见的，治表不及里，不是正法。而里邪又有夹寒夹热的不同，所以制小青龙汤以治表热里寒，制大青龙汤以治表寒里热，这是表中便兼解里，不必像坏病那样先里后表、先表后里地再算计。但是大、小青龙汤，即是麻黄汤、桂枝汤的变化，只足以解营卫之表，不足以驱腠理之邪。而且邪气留在腠理之间，半表之往来寒热虽相同，而半里又有夹虚夹实的悬殊。因此制小柴胡汤以防半里之虚，大柴胡汤以除半里之实，这是表中便兼和里，不必像后人那样先攻后补、先补后攻地斟酌。攻里既有调胃承气汤了，然而里邪在上焦的有夹水夹痰的差异，在中焦的有初硬后溏、燥屎定硬的区别，不是调胃承气汤所能平复的。因此制小陷胸汤以清胸膈之痰，大陷胸汤以下胸膈之水，小承气汤以试胃家之矢气，大承气汤以攻肠胃之燥屎，方有分寸，邪气去而元气无伤，不致有顾此遗彼、太过不及的祸患。按：发表攻里的方子，各有缓急之法。如麻黄汤、大承气汤是汗下之急剂，而桂枝汤则是发表之缓剂。其用桂枝汤诸法，是缓汗中更有轻重了。小承气汤是下之缓剂，说“少与之令小安”，说“微和胃气”，说“不转矢气者勿更与之”。调胃承气汤是下之尤缓者，说“少少温服之”，且不用气分药，更加甘草。是缓下中亦有差别了。至于奇偶之法，各方既已备见，而更有麻黄桂枝各半汤之偶，有桂枝二麻黄一汤之奇，是奇偶之中各有浅深。服桂枝汤后，须再喝热粥，成为复方了，而更有取小柴胡汤一升加芒硝之复，是复中又分汗下二法了。若白散之用复方更奇异，不利，进热粥一杯，利不止，进冷粥一杯，是一杯粥中又寓热泻冷补之二法。
病有虚热相关，寒热夹杂，有时药力所不能到的地方，仲景或用针或用灸来治疗。自从后世针、药分为两途，刺者不用药，用药者不刺，哪里知道古人刺、药相辅相成的道理。按岐伯治疗风厥，表里兼刺，饮之以汤药。所以仲景治疗太阳中风，服桂枝汤后反而烦……
In all diseases, there are names and symptoms, mechanisms and conditions. For example, wind-stroke (Zhongfeng), cold damage (Shanghan), warm diseases (Wenbing), summerheat diseases (Shu Bing), dampness diseases (Shi Bing), and spasm diseases (Jing Bing) belong to the category of "names" (disease nomenclature). External manifestations include headache, body pain, and lower back pain; internal manifestations include wheezing and coughing, vexation and thirst, vomiting and diarrhea, and abdominal fullness. These constitute the "symptoms" (Zheng). The location of the pathogen in the exterior or interior, the presence or absence of sweating, the pulse being floating or sunken, and the pulse force being strong or weak, represent the "mechanism" (Ji - key pathological mechanism). At this time, aversion to cold or heat, chest and hypochondriac fullness with a tendency to vomit, ability or inability to eat, desire to sleep but inability to do so, drinking several liters of water, or swishing water in the mouth without swallowing, are all "conditions" (Qing - specific clinical presentations). Formulating prescriptions based solely on disease names is the work of crude physicians; determining prescriptions based on symptoms is the work of average physicians; examining the pathological mechanism and observing the clinical condition within the symptoms is the work of excellent physicians. Zhang Zhongjing formulated prescriptions without being bound by disease names, but only by seeking accuracy in symptoms. By mastering the mechanism and understanding the condition, for any wind-stroke, cold damage, or miscellaneous disease, he would select the appropriate prescription effortlessly, employing flexible methods without exception. This is what is meant by "physicians do not adhere rigidly to fixed prescriptions." Today, those who discuss Zhongjing's prescriptions claim that Guizhi Tang (Cinnamon Twig Decoction) treats wind-stroke but not cold damage, and Mahuang Tang (Ephedra Decoction) treats cold damage but not wind-stroke. They fail to examine which symptoms Zhongjing's prescriptions primarily address, nor do they analyze which herbs Zhongjing used for specific symptoms. Instead, they merely compare wind-stroke and cold damage symptoms and speculate on names like Qinglong (Azure Dragon) and Baihu (White Tiger), thereby turning Zhongjing's flexible prescriptions and methods into rigid ones.
Zhongjing's prescriptions are exquisite and non-mixed, with six main formulas serving as the foundation from which others are modified. All diaphoretic (sweating-inducing) prescriptions are based on Guizhi Tang (Cinnamon Twig Decoction); all emetic prescriptions are based on Zhizi Chidao Tang (Gardenia and Fermented Soybean Decoction); all purgative prescriptions are based on Chengqi Tang (Order the Qi Decoction); all harmonizing prescriptions are based on Chaihu Tang (Bupleurum Decoction); all cooling prescriptions are based on Xiexin Tang (Drain the Epigastrium Decoction); and all warming prescriptions are based on Sini Tang (Reverse the Extremities Decoction). The count of one hundred and thirteen prescriptions mixed together results from a lack of careful examination.
Each of the Six Meridians has its primary governing prescription, yet there is subtle mutual applicability among them. For instance, Mahuang Tang (Ephedra Decoction) and Guizhi Tang (Cinnamon Twig Decoction) were established for Taiyang (Greater Yang) disharmony of Ying (Nutrient) and Wei (Defensive) levels, yet they are also used when Yangming (Yang Brightness) pathology involves the Ying and Wei levels. Zhenwu Tang (True Warrior Decoction) was established for Shaoyin (Lesser Yin) water qi pathology, yet it is also used for Taiyang pathology involving yang collapse after sweating. Sini Tang (Reverse the Extremities Decoction) was established for Taiyin (Great Yin) diarrhea with undigested food, yet it is suitable for Taiyang pathology where the pulse is unexpectedly sunken. Wuling San (Five-Ingredient Powder with Poria) was established for Taiyang polydipsia and water regurgitation, yet it is also suitable for Yangming pathology involving excessive water intake. Zhuling Tang (Poria Decoction) was established for Shaoyin diarrhea, yet it is also suitable for Yangming pathology involving difficult urination. Didang Tang (Arriving at the Blood Stasis Decoction) was established for Taiyang blood stasis in the interior, yet it is also used for Yangming blood accumulation. Gouti San (Melon Tip Powder) was established for Yangming epigastric hardness and oppression, yet it is also used for Shaoyin pathology involving a persistent urge to vomit. When symptoms match, the corresponding prescription is used. Although each prescription belongs to a specific meridian, its application need not be restricted. This is Zhongjing's method. Zhongjing's prescriptions differ only in terms of exterior/interior, cold/heat, and deficiency/excess, without distinct separation between cold damage, wind-stroke, or miscellaneous diseases. There is a subtlety in alternating two prescriptions for wind-cold, and a uniqueness in exchanging two prescriptions for exterior/interior issues. Some achieve success with the complete formula, while others achieve results through modifications. Later scholars discussed prescriptions without analyzing symptoms, making Zhongjing's prescriptions seem difficult to use. Guizhi Tang (Cinnamon Twig Decoction) is the premier diaphoretic agent. Mahuang (Ephedrae Herba) penetrates directly through the skin and hair follicles, while Shengjiang (Zingiberis Rhizoma Recens) disperses horizontally through the muscles. Therefore, when Guizhi Tang (Cinnamon Twig Decoction) assists Mahuang Tang (Ephedra Decoction), it opens the Xuankou (pores) and expels pathogens from the Wei (Defensive) level, inducing sweating in those who have none, thus termed "inducing sweating." When Guizhi Tang (Cinnamon Twig Decoction) leads Shengjiang (Zingiberis Rhizoma Recens), it opens the Couli (interstices) and drives out pathogens from the Ying (Nutrient) level, inducing sweating in those who already sweat, thus termed "releasing the muscle layer." Releasing the muscle layer means resolving pathogens in the muscle layer, which resides in the Ying level. Why do proponents of the "Three Guidelines" theory claim Mahuang manages Ying and Guizhi manages Wei? Mahuang Tang does not explicitly mention releasing the muscle layer, yet the muscle layer is invariably resolved; Guizhi Tang's release of the muscle layer is precisely how it induces sweating. It must be understood that Mahuang Tang (Ephedra Decoction) and Guizhi Tang (Cinnamon Twig Decoction) represent methods of inducing sweating at different depths. Sweating should not be attributed solely to Mahuang, nor should releasing the muscle layer be contrasted against inducing sweating. Previous scholars discussed these two prescriptions as topics of conversation rather than using them clinically.
When wind-cold invades the human body, if it does not enter the Ying and Wei levels, it enters the Couli (interstices). Zhongjing formulated Guizhi Tang (Cinnamon Twig Decoction) to harmonize Ying and Wei, and Chaihu Tang (Bupleurum Decoction) to harmonize the Couli. Observing the Six Meridians' symptoms, Zhongjing uniquely coined the terms "Guizhi Syndrome" and "Chaihu Syndrome," indicating that these two prescriptions bear significant responsibility and cannot be confined to a single meridian. Only the Taiyang (Greater Yang) meridian governs the Qi of all Yang meridians, and all exterior syndromes of the Six Meridians belong to Taiyang. Thus, Chaihu Tang (Bupleurum Decoction) stands in opposition to Guizhi Tang (Cinnamon Twig Decoction) within the Taiyang sector. Guizhi Tang (Cinnamon Twig Decoction) was originally established for Taiyang wind-cold; it is suitable for any initial external pathogen affecting the Six Meridians that has not yet left the Ying and Wei levels. Chaihu Tang (Bupleurum Decoction) was originally established for Shaoyang (Lesser Yang) semi-exterior/semi-interior locations; it is suitable for any pathogen of the Three Yang meridians lingering in the semi-exterior/semi-interior Couli. Zhongjing valued these two prescriptions highly, providing annotations for both Guizhi Syndrome and Xiao Chaihu Tang (Minor Bupleurum Decoction). Both Guizhi and Chaihu syndromes have ambiguous presentations. Both can develop into "transformed diseases" (Huabing). Once the Guizhi syndrome resolves, Guizhi Tang (Cinnamon Twig Decoction) is no longer applicable, but subsequent treatments still rely on modifications of the Guizhi Tang (Cinnamon Twig Decoction) formula. Once the Chaihu syndrome resolves, Xiao Chaihu Tang (Minor Bupleurum Decoction) is no longer applicable, but rescue methods still rely on modifications of the Xiao Chaihu Tang (Minor Bupleurum Decoction) formula.
Mahuang Tang (Ephedra Decoction) syndrome features heat entirely in the exterior. Guizhi Tang (Cinnamon Twig Decoction) syndrome features spontaneous sweating, and Da Qinglong Tang (Major Azure Dragon Decoction) syndrome features vexation and restlessness; both involve interior heat. In exterior-releasing formulas, Zhongjing incorporates cold-natured herbs to clear interior heat. Spontaneous sweating is a precursor to vexation; restlessness is a sign of vexation. When sweating occurs, vexation can dissipate outward, so restlessness does not occur; mild cold, sour, and bitter flavors are used to harmonize. When sweating does not occur, vexation cannot dissipate, leading to restlessness; major cold and heavy substances are used to clear heat. Shaoyao (Paeoniae Radix Alba) and Shigao (Gypsum Fibrosum) are interior herbs included in exterior formulas. Modern practitioners, failing to recognize interior involvement in exterior patterns, hesitate and fail to use them, allowing heat to merge into the Yangming stage, resulting in macules, jaundice, mania, and confusion. This failure is due to an inability to appropriately use Da Qinglong Tang (Major Azure Dragon Decoction). Zhongjing uses Shigao (Gypsum Fibrosum) in the Taiyang meridian to clear stomach fire, a preemptive measure to protect the Yangming meridian; adding Jiang (Zingiberis Rhizoma) and Zao (Jujubae Fructus) nourishes the middle, anticipating potential transmission to the Taiyin meridian.
Xiao Qinglong Tang (Minor Azure Dragon Decoction) and Chaihu Tang (Bupleurum Decoction) are both exterior-interior dual-resolving formulas. Xiao Qinglong Tang (Minor Azure Dragon Decoction) focuses on interior symptoms, while Xiao Chaihu Tang (Minor Bupleurum Decoction) focuses on exterior symptoms. Therefore, in modifications of Xiao Qinglong Tang (Minor Azure Dragon Decoction), Mahuang (Ephedrae Herba) may be removed; in modifications of Xiao Chaihu Tang (Minor Bupleurum Decoction), Chaihu (Bupleuri Radix) remains unique. This is because Xiao Qinglong Tang (Minor Azure Dragon Decoction) focuses on water retention in the semi-interior, while Xiao Chaihu Tang (Minor Bupleurum Decoction) focuses on heat in the semi-exterior. Xiao Qinglong Tang (Minor Azure Dragon Decoction) treats water qi from unresolved cold damage, using warm agents to induce sweating and disperse; Shizao Tang (Ten Jujube Decoction) treats water qi from resolved wind-stroke, using cold agents to guide and exhaust the pathogen. This illustrates the different treatments for cold-water and wind-water pathologies. The water treated by Xiao Qinglong Tang (Minor Azure Dragon Decoction) is moving and unsettled; the water treated by Wuling San (Five-Ingredient Powder with Poria) is stagnant and immobile; the water treated by Shizao Tang (Ten Jujube Decoction) is unrestrained; the water treated by Daxiexiong Tang (Major Chest Trap Decoction) presents as oppression, hardness, firmness, and fullness; the water treated by Zhenwu Tang (True Warrior Decoction) causes heaviness in the four limbs. Since water pathologies vary, treatment methods differ.
Lin Yi stated: "Xiexin Tang (Drain the Epigastrium Decoction) was originally named Lizhong Huanglian Renshen Tang (Spleen-Nourishing Coptis and Ginseng Decoction), as treating epigastric obstruction with Xiexin Tang (Drain the Epigastrium Decoction) aligns with the function of Lizhong Tang (Regulate the Middle Decoction)." One must understand that Zhongjing used Lizhong Tang (Regulate the Middle Decoction) with both cold and heat methods: one to support Yang, the other to benefit Yin. When pathogens reside between Ying and Wei, sweating is the only exit, hence Mahuang Tang (Ephedra Decoction) and Guizhi Tang (Cinnamon Twig Decoction) were established. When pathogens reside between the chest and abdomen, vomiting is the only exit, hence Gouti San (Melon Tip Powder) and Zhizi Chi Dao Tang (Gardenia and Fermented Soybean Decoction) were established. Gouti San (Melon Tip Powder) treats epigastric hardness and oppression, addressing the Upper Jiao (Upper Burner); Zhizi Chi Dao Tang (Gardenia and Fermented Soybean Decoction) treats abdominal fullness and wheezing, addressing the Middle Jiao (Middle Burner). This parallels Mahuang Tang (Ephedra Decoction) targeting the skin and Guizhi Tang (Cinnamon Twig Decoction) targeting the muscles. Gouti San (Melon Tip Powder) is a harsh agent, similar to Mahuang Tang (Ephedra Decoction) which should not be used lightly; Zhizi Chi Dao Tang (Gardenia and Fermented Soybean Decoction) is a mild agent, similar to Guizhi Tang (Cinnamon Twig Decoction) which can be reused without harm. Thus, Taiyang exterior formulas often modify Guizhi Tang (Cinnamon Twig Decoction); Yangming exterior formulas often modify Zhizi Chi Dao Tang (Gardenia and Fermented Soybean Decoction). Using Zhizi Chi Dao Tang (Gardenia and Fermented Soybean Decoction) in Yangming is like using Guizhi Tang (Cinnamon Twig Decoction) in Taiyang: just as it can expel pathogens, it can also rescue deviations. Modern practitioners know only that sweating resolves the exterior, unaware that vomiting also resolves the exterior. They know the saying that vomiting contains dispersing properties but do not understand the rationale for vomiting. Consequently, within Zhongjing's great methods, they take sweating and purging but omit vomiting.
Shaoyang (Lesser Yang) acts as the pivot, neither fully interior nor fully exterior. Zhongjing's original intent emphasized the interior, yet Chaihu Tang (Bupleurum Decoction) governs the semi-interior. Therefore, semi-exterior conditions must be present to justify modifying Xiao Chaihu Tang (Minor Bupleurum Decoction). If the pathogen is entirely interior, Chaihu Tang (Bupleurum Decoction) is not indicated, hence it is called an exterior-resolving formula. Although Xiao Chaihu Tang (Minor Bupleurum Decoction) treats semi-exterior conditions, it essentially regulates the Qi of the Three Jiao (Three Burners), earning it the title of "pivot agent." Symptoms such as chest fullness, epigastric vexation, heart vexation, epigastric palpitations, cough, thirst, and a tendency to vomit indicate a lack of developmental mechanism in the Upper Jiao (Upper Burner). Abdominal fullness and hypochondriac hardness indicate a failure of transport mechanism in the Middle Jiao (Middle Burner). Difficult urination indicates a loss of drainage function in the Lower Jiao (Lower Burner). These result from the struggle between pathogenic factors and righteous Qi. Ren Shen (Ginseng Radix et Rhizoma) is used to support the righteous Qi of the Three Jiao (Three Burners) and strengthen the pivot.
In Shaoyin (Lesser Yin) disease lasting two to three days, with heart vexation and inability to sleep, the root pathology lies in the Heart. The method should nourish the true fire within Li (Fire), following its moistening downward trend. Thus, Huang Lian (Coptidis Rhizoma) is used as the sovereign herb for its bitter cold nature to drain heat. On the fourth to fifth day, with difficult urination and pus/blood in stool, the root pathology lies in the Kidney. The method should raise the minor fire within Kan (Water), following its flaming upward trend. Thus, Gan Jiang (Zingiberis Rhizoma) is used as an assistant herb for its bitter warm nature to disperse. This distinguishes the "hidden brightness fire" from the "ascending brightness fire." In Shaoyin (Lesser Yin) disease with vexation and drowsiness, progressing to five to six days with an urge to vomit without success, spontaneous diarrhea with thirst, and white urine, the Lower Jiao (Lower Burner) is deficient and cold, unable to control water. Zhenwu Tang (True Warrior Decoction) is indicated to warm the Kidney water of the Lower Jiao (Lower Burner). With diarrhea lasting six to seven days, accompanied by cough, vomiting, thirst, heart vexation, and insomnia, the Upper Jiao (Upper Burner) has deficient heat, and fluid metabolism is impaired. Zhuling Tang (Poria Decoction) is indicated to unblock the fluids of the Upper Jiao (Upper Burner).
Sini Tang (Reverse the Extremities Decoction) is the principal formula for Taiyin (Great Yin), yet it can be used across meridians. In Taiyin (Great Yin), it consolidates the root to expel pathogens; in Shaoyin (Lesser Yin), it warms Earth to control Water; in Jueyin (Terminal Yin), it harmonizes Earth to generate Wood; in Taiyang (Greater Yang), it benefits Fire to support primal Yang. It is unsuitable for Yangming (Yang Brightness) stomach excess and Shaoyang (Lesser Yang) ministerial fire.
In Shaoyin (Lesser Yin) disease lasting four to five days, with abdominal pain, difficult urination, and incessant diarrhea: if accompanied by heaviness and pain in the four limbs, it indicates Lower Jiao (Lower Burner) water stagnation; Zhenwu Tang (True Warrior Decoction) is used, representing the method of guiding fire back to its source. If accompanied by pus and blood in stool, it indicates Lower Jiao (Lower Burner) fire stagnation; Taohua Tang (Peach Blossom Decoction) is used, representing the method of raising Yang and scattering fire. This is due to deficiency of Yang in Kan (Water); difficult urination should not be treated as heat.
Xiao Chaihu Tang (Minor Bupleurum Decoction) is the principal formula for Shaoyang (Lesser Yang); Wu Mei Wan (Mume Pill) is the principal formula for Jueyin (Terminal Yin). Although different, their methods of combining cold/warm and tonifying/purging are compatible due to connected zang-fu organs, interwoven meridians, shared Wind-Wood Qi, and joint governance of Ministerial Fire. Both use Ren Shen (Ginseng Radix et Rhizoma) to tonify the middle and boost Qi to consolidate the root and expel pathogens. Other ingredients do not overlap due to differing Yin-Yang positions. Yang favors ascending and dispersing, so Chaihu (Bupleuri Radix) is primary; Yin favors gathering and descending, so Wu Mei (Mume Fructus) is primary. Yang governs heat, so cold/cool herbs are heavily used; Yin governs cold, so acrid/warm herbs are heavily used. Yang functions through movement, so decoctions are used to sweep away pathogens; symptoms are variable, hence Xiao Chaihu Tang (Minor Bupleurum Decoction) has modification rules. Yin functions through stillness, so pills are used to缓 (slow/relax); symptoms are fixed, hence Wu Mei Wan (Mume Pill) has no modification rules.
For Jueyin (Terminal Yin) diarrhea, Baitouweng Tang (Pulsatilla Decoction) is used to raise Yang and scatter fire, embodying the principle of "dispersing constrained fire." Wu Mei Wan (Mume Pill) is formulated to gather fire, embodying the meaning of "bending and straightening producing acidity." Bitter-cold herbs harmonize Yin; warm-tonifying herbs preserve Yang. This is the method of regulating Qi in the Liver. Because it treats reversal cold-diarrhea and chronic diarrhea, it half-comprises warm-tonifying elements. Baitouweng Tang (Pulsatilla Decoction) treats wind-heat diarrhea with tenesmus, focusing purely on cooling and dispersing.
Commentary: Releasing the exterior and purging the interior are chief techniques for resisting pathogens. Exterior syndromes are caused by wind-cold; if exterior herbs are cold-natured, exterior heat will not subside, and interior cold will arise. Thus, exterior herbs must include Guizhi (Cinnamomi Ramulus); releasing the exterior does not avoid heat. However, this applies only to Taiyang (Greater Yang) exterior heat. For Yangming (Yang Brightness) and Shaoyang (Lesser Yang) fever, herbs like Chaihu (Bupleuri Radix), Huang Qin (Scutellariae Radix), Zhizi (Gardeniae Fructus), and Chi Xiao Dou (Sojae Semen Praeparatum) should be used. Interior syndromes are caused by constrained heat; if purgatives are not bitter-cold, constrained heat will not be removed, and pathogens will have no exit. Thus, purgative agents must use Da Huang (Rhei Radix et Rhizoma); purging the interior does not avoid cold. However, this applies only to Yangming (Yang Brightness) stomach heat. For aversion to cold, epigastric hardness, and Yang deficiency with Yin binding, herbs like Gan Jiang (Zingiberis Rhizoma), Fu Zi (Aconiti Lateralis Radix Preparata), and Ba Dou (Crotonis Fructus) should be added.
Mahuang Tang (Ephedra Decoction) and Guizhi Tang (Cinnamon Twig Decoction) are exterior herbs for Taiyang (Greater Yang) and Yangming (Yang Brightness) exterior syndromes. Gouti San (Melon Tip Powder) and Zhizi Chi Dao Tang (Gardenia and Fermented Soybean Decoction) are exterior herbs for Yangming (Yang Brightness) interior syndromes. Xiao Chaihu Tang (Minor Bupleurum Decoction) is an exterior herb for Shaoyang (Lesser Yang) semi-exterior syndromes. The exterior herb for Taiyin (Great Yin) is Guizhi Tang (Cinnamon Twig Decoction); for Shaoyin (Lesser Yin), it is Mahuang Fuzi Xixin Tang (Ephedra, Prepared Aconite, and Asarum Decoction); for Jueyin (Terminal Yin), it is Danggui Sini Tang (Angelica Sinensis Decoction for Reversal Cold). The use of exterior herbs in the Six Meridians provides an exit for wind-cold pathogens.
Reversal cold of the hands and feet varies by cold/heat and exterior/interior. Sini San (Bupleurum Powder for Reversal Cold) resolves Shaoyin (Lesser Yin) interior heat; Danggui Sini Tang (Angelica Sinensis Decoction for Reversal Cold) resolves Jueyin (Terminal Yin) exterior cold; Tongmai Sini Tang (Unblocking the Vessels Reverse the Extremities Decoction) rescues the impending collapse of Shaoyin (Lesser Yin) true Yang; Fuling Sini Tang (Poria Reverse the Extremities Decoction) preserves the impending depletion of Taiyin (Great Yin) true Yin. These four formulas differ in severity and depth across meridians.
The Bladder governs water and is the interior of Taiyang (Greater Yang); Shizao Tang (Ten Jujube Decoction) and Wuling San (Five-Ingredient Powder with Poria) are purgatives for the Taiyang (Greater Yang) water pathways. The Stomach governs grain and is the interior of Yangming (Yang Brightness); the three Chengqi Tangs (Order the Qi Decoctions) are purgatives for the Yangming (Yang Brightness) grain pathways. The Gallbladder governs Qi and is the interior of Shaoyang (Lesser Yang); Da Chaihu Tang (Major Bupleurum Decoction) is a purgative for Shaoyang (Lesser Yang) Qi level. These three Yang purgatives provide an exit for excess pathogens in the Three Yang meridians. The Large Intestine and Small Intestine belong to the Stomach; when the Stomach house is excess, both intestines are excess. Dividing them: Tiaowei Chengqi Tang (Regulate the Stomach Order the Qi Decoction) is the purgative for the Stomach house; Xiaochengqi Tang (Minor Order the Qi Decoction) is the purgative for the Small Intestine; Dachengqi Tang (Major Order the Qi Decoction) is the purgative for the Large Intestine. Wu (Earth) is dry soil; Geng (Metal) is dry metal; thus, Mangxiao (Natrii Sulfas) is added to moisten dryness. Guizhi Jiadahuang Tang (Cinnamon Twig Plus Rhubarb Decoction) is a purgative for Taiyang (Greater Yang) transmitting to Yangming (Yang Brightness); Guizhi Jiashao Yao Tang (Cinnamon Twig Plus Peony Decoction) is a purgative for Taiyang (Greater Yang) transmitting to Taiyin (Great Yin).
Purgatives combined with exterior herbs are used because the pathogen has not fully left the exterior. Chaihu Jianiaoxiao Tang (Bupleurum Plus Natrii Sulfas Decoction) is a purgative for Shaoyang (Lesser Yang) transmitting to Yangming (Yang Brightness). Da Chaihu Tang (Major Bupleurum Decoction) purges formless pathogens in Shaoyang (Lesser Yang); Chaihu Jianiaoxiao Tang (Bupleurum Plus Natrii Sulfas Decoction) purges formed pathogens in Shaoyang (Lesser Yang). Guizhi Jiashao Yao Tang (Cinnamon Twig Plus Peony Decoction) purges formless pathogens in Taiyin (Great Yin); Sanwu Baisan (Three-Ingredient White Powder) purges formed pathogens in Taiyin (Great Yin). Sini San (Bupleurum Powder for Reversal Cold) purges formless pathogens in Shaoyin (Lesser Yin) and Jueyin (Terminal Yin); Chengqi Tangs (Order the Qi Decoctions) purge formed pathogens in various meridians. There is a distinction in severity: mild purgatives use only Qi-level herbs; severe purgatives combine Blood-level herbs. Sour-bitter inducing discharge is mild purgation, so Shaoyao (Paeoniae Radix Alba) and Zhishi (Aurantii Fructus Immaturus) are mild; salty-bitter inducing discharge is severe purgation, so Da Huang (Rhei Radix et Rhizoma) and Mangxiao (Natrii Sulfas) are severe.
Zhongjing's use of "purge" does not refer exclusively to defecation. When giving Guizhi Tang (Cinnamon Twig Decoction) to attack the exterior, it refers to sweating; when the exterior is resolved and one may then attack, it refers to promoting urination; when heat belongs to the Zang organs and is attacked, it refers to clearing fire. Cold-dampness in the interior should not be purged via defecation; referring to promoting urination. Because there is heat, one should use a decoction to purge; referring to clearing fire.
Zhongjing's purgatives focus on decoctions, hence stating that physicians using pill-based purgation is incorrect. Examining Xiantiong Wan (Chest Trap Pill) and Didang Wan (Arriving at Blood Stasis Pill), they are still prepared with water, effectively restoring the power of decoctions. Taking approximately two ounces, including dregs, makes their potency stronger than decoctions or powders. One must understand that Zhongjing's prescriptions measured in Zhu, Liang, and Fen are not for exogenous diseases; pills the size of tung seeds, taken ten at a time, are not methods for treating exogenous diseases.
Zhongjing established prohibitions alongside his prescriptions to ensure patients benefit without suffering side effects. For example, when using exterior-releasing herbs, if sweating occurs after one dose, stop subsequent doses. If the pulse is floating-tight, with fever and no sweating, do not give Guizhi Tang (Cinnamon Twig Decoction); if the pulse is weak-thin, with sweating and aversion to wind, do not administer Da Qinglong Tang (Major Azure Dragon Decoction); if the pulse is floating with fever and no sweating, with unresolved exterior, do not give Baihu Tang (White Tiger Decoction); for all patients with blood loss or deficiency, do not use Gouti San (Melon Tip Powder); for patients with a history of loose stools, do not give Zhizi Chi Dao Tang (Gardenia and Fermented Soybean Decoction); for Yangming (Yang Brightness) disease with excessive sweating, do not give Zhuling Tang (Poria Decoction); if the exterior is unresolved and heat is not tidal, do not give Chengqi Tang (Order the Qi Decoction); for patients prone to vomiting, do not give Jianzhong Tang (Establish the Middle Decoction). These are all cautious measures by Zhongjing. Zhongjing's modifications hold deep meaning. For abdominal pain: add Shaoyao (Paeoniae Radix Alba) in Shaoyang (Lesser Yang), Fuzi (Aconiti Lateralis Radix Preparata) in Shaoyin (Lesser Yin), and Renshen (Ginseng Radix et Rhizoma) in Taiyin (Great Yin). For epigastric palpitations: add Guizhi (Cinnamomi Ramulus) in Shaoyin (Lesser Yin) and Fuling (Polyporus) in Shaoyang (Lesser Yang). For thirst: add Gualugen (Trichosanthis Radix) and Renshen (Ginseng Radix et Rhizoma) in Shaoyang (Lesser Yang), and Baizhu (Atractylodis Macrocephalae Rhizoma) in Taiyin (Great Yin). Modifications distinguish Yin-Yang and Exterior-Interior thus. Carefully studying Zhongjing's prescriptions reveals the wonder of symptom-based formulation; understanding his modification rules reveals the precision of his herb selection.
Xiao Qinglong Tang (Minor Azure Dragon Decoction) lists five possible symptoms, with five corresponding modification formulas. Xiao Chaihu Tang (Minor Bupleurum Decoction) lists seven possible symptoms, with seven corresponding modification formulas. Understand that Zhongjing has primary governing formulas, such as Mahuang Tang (Ephedra Decoction) and Guizhi Tang (Cinnamon Twig Decoction); he has formulas outside formulas, such as Guizhi Tang (Cinnamon Twig Decoction) plus Fuzi (Aconiti Lateralis Radix Preparata) or Dahuang (Rhei Radix et Rhizoma); he has formulas within formulas, such as the modification rules for Qinglong Tang (Azure Dragon Decoction) and Zhenwu Tang (True Warrior Decoction). Zhongjing's writing contains methods within methods, and formulas outside formulas. How can one be constrained by 397 methods and 113 prescriptions?
In ancient times, Qibo created the Seven Prescriptions to treat diseases. Zhongjing further explored the variability of diseases to exhaust their subtleties. Releasing the exterior and purging the interior are major methods for expelling pathogens, with formulas varying in size, such as Qinglong Tang (Azure Dragon Decoction), Chaihu Tang (Bupleurum Decoction), Xiantiong Tang (Chest Trap Decoction), and Chengqi Tang (Order the Qi Decoction). Since exterior-releasing formulas like Mahuang Tang (Ephedra Decoction) and Guizhi Tang (Cinnamon Twig Decoction) exist, if interior pathogens accompany exterior ones, treating only the exterior is incomplete. Interior pathogens may accompany cold or heat. Thus, Xiao Qinglong Tang (Minor Azure Dragon Decoction) treats exterior heat with interior cold, and Da Qinglong Tang (Major Azure Dragon Decoction) treats exterior cold with interior heat, resolving the interior within the exterior treatment, avoiding the sequential calculations required for transformed diseases. However, Da and Xiao Qinglong Tangs are variations of Mahuang and Guizhi Tangs, sufficient only for Ying-Wei exterior, not for Couli pathogens. Pathogens lingering in the Couli share the alternating chills and fever of the semi-exterior, but the semi-interior may involve deficiency or excess. Thus, Xiao Chaihu Tang (Minor Bupleurum Decoction) prevents semi-interior deficiency, and Da Chaihu Tang (Major Bupleurum Decoction) removes semi-interior excess, harmonizing the interior within the exterior treatment, avoiding the sequential tonification/purging debates of later scholars. Since Tiaowei Chengqi Tang (Regulate the Stomach Order the Qi Decoction) exists for purging the interior, if interior pathogens are in the Upper Jiao (Upper Burner), they may involve water or phlegm; if in the Middle Jiao (Middle Burner), stool may be initially hard then loose, or firmly dry. Tiaowei Chengqi Tang (Regulate the Stomach Order the Qi Decoction) cannot resolve these. Thus, Xiaoxiantiong Tang (Minor Chest Trap Decoction) clears phlegm in the chest/diaphragm; Daxiantiong Tang (Major Chest Trap Decoction) drains water in the chest/diaphragm; Xiaochengqi Tang (Minor Order the Qi Decoction) tests stomach gas; Dachengqi Tang (Major Order the Qi Decoction) attacks dry feces in the intestines. This ensures precision, expelling pathogens without damaging righteous Qi, avoiding neglect or excess. Commentary: Exterior-releasing and interior-purging formulas have varying speeds. Mahuang Tang (Ephedra Decoction) and Dachengqi Tang (Major Order the Qi Decoction) are urgent sweating and purging agents, while Guizhi Tang (Cinnamon Twig Decoction) is a slow exterior-releasing agent. Its methods show gradations within slow sweating. Xiaochengqi Tang (Minor Order the Qi Decoction) is a slow purgative; instructions say "give little to achieve slight relief," "slightly harmonize stomach Qi," and "do not give more if no gas passes." Tiaowei Chengqi Tang (Regulate the Stomach Order the Qi Decoction) is even slower; instructions say "take small amounts warm," and it omits Qi-moving herbs, adding Gancao (Glycyrrhizae Radix et Rhizoma). Thus, differences exist within slow purgation. Regarding odd/even methods, while various formulas are seen, there is the even combination of Mahuang-Guizhi Ge Ban Tang (Half-Mahalf-Guizhi Decoction) and the odd combination of Guizhi Er Mahuang Yi Tang (Two Parts Cinnamon Twig, One Part Ephedra Decoction), showing depth within odd/even. After taking Guizhi Tang (Cinnamon Twig Decoction), drinking hot porridge creates a compound formula. Further, taking one sheng of Xiao Chaihu Tang (Minor Bupleurum Decoction) plus Mangxiao (Natrii Sulfas) creates another compound, dividing sweating and purging within compounds. Bai San (White Powder) uses compound methods differently: if no diarrhea, drink a cup of hot porridge; if diarrhea persists, drink a cup of cold porridge. One cup of porridge contains both heat-dispersing and cold-tonifying methods.
Diseases involving deficient heat, mixed cold-heat, or areas unreachable by medicine may be treated by Zhongjing with acupuncture or moxibustion. Since later ages separated acupuncture and herbal medicine, with acupuncturists avoiding herbs and herbalists avoiding needles, few understand the complementary nature of needle and drug therapy. According to Qibo, treating Fengjue (Wind-Jue) involved simultaneous exterior-interior acupuncture and herbal decoctions. Thus, Zhongjing treated Taiyang (Greater Yang) wind-stroke; after taking Guizhi Tang (Cinnamon Twig Decoction), vexation反而 (instead/reversely)...