白虎汤及白虎加人参汤两方，皆治足阳明有实热者也。至热入手阳明之府，致大便因热燥结，其燥结
愈甚者，蕴蓄之热必愈深，此非开其燥结其热固不能消也。若斯则攻下之剂，若承气汤诸方在所必需矣。
《伤寒论》原文∶阳明病脉迟，虽汗出不恶寒者，其身必重，短气腹满而喘，有潮热者，此外欲解，
可攻里也。手足 然而汗出者，此大便已硬也，大承气汤主之。若汗多，微发热恶寒者，外来未也，其热
不潮，未可与承气汤。若腹大满不通者，可与小承气汤，微和胃气，勿令大泄下。
首句为阳明病脉迟，此见阳明病脉迟为当下之第一明征也。而愚初度此句之义，以为凡伤寒阳明之当
下者，若其脉数，下后恒至不解，此言脉迟，未必迟于常脉，特表明其脉不数，无虑其下后不解耳。迨至阅历
既久，乃知阳明病当下之脉原有迟者。然其脉非为迟缓之象，竟若蓄极而通，有迟而突出之象。盖其脉之
迟，因肠中有阻塞也。其迟而转能突出者，因阳明火盛，脉原有力，有阻其脉之力而使之迟者，正所以激
其脉之力而使有跳跃之势也。如此以解脉迟，则脉迟之当下之理自明也。
然愚临证实验以来，知阳明病既当下，其脉迟者固可下，即其脉不迟而亦不数者，亦可下。惟脉数及六
至则不可下，即强下之，病必不解，或病更加剧。而愚对于此等证，原有变通之下法，即白虎加人参汤，
将石膏不煎入汤中，而以所煎之汤将石膏送服者是也。愚因屡次用此方奏效，遂名之为白虎承气汤，爰详
录之于下，以备医界采用。
生石膏八钱捣细，大潞党参三钱，知母八钱，甘草二钱，粳米二钱。药共五味，将后四味煎汤一盅半，
分两次将生石膏细末用温药汤送下。服初次药后，迟两点钟，若腹中不见行动，再服第二次。若腹中已见
行动，再迟点半钟大便已下者，停后服。若仍未下者，再将第二次药服下。至若其脉虽数而洪滑有力者，用
此方时亦可不加党参。
愚从前遇寒温证之当下而脉象数者，恒投以大剂白虎汤，或白虎加人参汤，其大便亦可通下。然生石
膏必须用至四五两，煎一大碗，分数次温服，大便始可通下。间有服数剂后大便仍不通
下者，其人亦恒脉净身凉，少用玄明粉二三钱和蜜冲服，大便即可通下。然终不若白虎承气汤用之较便也。
生石膏若服其研细之末，其退热之力一钱可抵煎汤者半两。
若以之通其大便，一钱可抵煎汤者一两。是以方中只用生石膏八
钱，而又慎重用之，必分两次服下也。
寒温阳明病，其热甚盛者，投以大剂白虎汤，其热稍退，翌日恒病仍如故。如此反复数次，病家遂疑
药不对证，而转延他医，因致病不起者多矣。愚后拟得此方，凡遇投以白虎汤见效旋又反复者，再为治时
即用石膏为末送服。其汤剂中用五六两者，送服其末不过一两，至多至两半，其热即可全消矣。
【大承气汤方】大黄四两酒洗，浓朴半斤炙去皮，枳实五枚炙，芒硝三合。
上四味，以水一斗，先煮二物，取五升，去滓，纳大黄，煮取二
升，去滓，纳芒硝，更上微火一两沸，分温再服，得下，余勿服。
大承气汤方，所以通肠中因热之燥结也。故以大黄之性善攻下，且善泻热者为主药。然药力之行必恃
脏腑之气化以斡旋之，故佐以朴、实以流通肠中郁塞之气化，则大黄之攻下自易为力矣。用芒硝者，取其性
寒味咸，善清热又善软坚，且兼有攻下之力，则坚结之燥粪不难化为溏粪而通下矣。方中之用意如此，药味无
多，实能面面精到，而愚对于此方不无可疑之点，则在其药味分量之轻重也。
《神农本草经》谓大黄能推陈致新，是以有黄良之名，在阳明蕴有实热大便燥结者，原宜多用。至
浓朴不过为大黄之辅佐品，竟重用至半斤，较大黄之分量为加倍，若按一两为今之三钱折算，复分两次服之，
则一次所服之药，当有浓朴一两二钱。夫浓朴气温味辛，若多用之，能损人真气，为人所共知，而其性又
能横行达表，发出人之热汗。忆愚少时，曾治一阳明实热大便燥结证，方中用大黄三钱，服后大便未通下，
改延他医，方中重用浓朴一两，服后片时出热汗遍体，似喘非喘，气弱不足以息，未逾半日而亡矣。此诚可为
前车之鉴也。是以愚谓此方之分量必有差误，愚疑此方浓朴之分量，当亦如小承气汤为大黄分量之半，其原本
或为浓朴之分量半大黄，大抵由此半字而误为半斤也。
再者，本节原文以阳明病脉迟五字开端，所谓脉迟者，言其脉象虽热而至数不加数也（非谓其迟于平脉）。
此乃病者身体素壮，阴分尤充足之脉。病候至用大承气汤时，果能有如此脉象，投以大承气汤原方，亦可随
手奏效。而今之大承气汤证如此脉象者，实不多见也。此乃半关天时，半关人事，实为古今不同之点。即
浓朴之分量原本如是，医者亦当随时制宜为之通变化裁，方可为善师仲景之人。非然者，其脉或不迟而数，但
用硝、黄降之，犹恐降后不解，因阴虚不能胜其燥热也，况更重用浓朴以益其燥热乎？又或其脉纵不数，而
热实脉虚，但用硝、黄降之，犹恐降后下脱，因其气分原亏，不堪硝、黄之推荡也，况敢重用浓朴同枳实以
破其气乎？昔叶香岩用药催生，曾加梧桐叶一片作引，有效之者，转为香岩所笑。或问其故，香岩谓∶“余用
梧桐叶一片时，其日为立秋，取梧桐一叶落也。非其时，将用梧桐叶何为？”由斯知名医之治病，莫不因时制
宜，原非胶柱鼓瑟也。是以愚用承气汤时，大黄、芒硝恒皆用至七八钱，浓朴、枳实不过用二钱。或仿调胃
承气汤之义，皆减去不用，外加生赭石细末五六钱，其攻下之力不减大承气原方，而较诸原方用之实为稳
妥也。至其脉象数者，及脉象虽热而重按无力者，又恒先投以大剂白虎加人参汤，煎汤一大碗，分数
次温饮下，以化胃中燥热，而由胃及肠即可润其燥结，往往有服未终剂，大便即通下者。且下后又无虞其不
解，更无虑其下脱也。其间有大便未即通下者，可用玄明粉三钱，或西药留苦四钱，调以蜂蜜，开水冲服。或
外治用猪胆汁导法，或用食盐（若用熬火硝所出之盐更佳）融水灌肠，皆可通下。至通下之后，亦无不愈者。
【小承气汤方】大黄四两酒洗，浓朴二两炙去皮，枳实三枚大者炙。
上三味，以水四升，煮取一升二合，去滓，分温二服。初服汤当
更衣，不尔者尽饮之。若更衣者，勿服之。
大承气汤所主之病，大肠中有燥粪，是以用芒硝软坚以化其燥粪。小承气汤所主之病为腹大满不通，是其
病在于小肠而上连于胃，是以但用大黄、朴实以开通其小肠，小肠开通下行，大便不必通下，即通下亦不至多，
而胃中之食可下输于小肠，是以胃气得和也。此大、小承气汤用法之分别也。而二承气汤之外，又有调
胃承气汤，更可连类论及之。
【调胃承气汤方】大黄四两去皮清酒浸，甘草二两炙，芒硝半升。
上二味， 咀，以水三升，煮取一升，去滓，纳芒硝，再上火微煮令沸，少少温服之。
大黄虽为攻下之品，原善清血分之热，心中发烦实为血分有热也。大黄浸以清酒，可引其苦寒之性上行
以清心之热而烦可除矣。证无大便燥结而仍用芒硝者，《内经》谓热淫于内治以咸寒。芒硝味咸性寒，实
为心家对宫之药（心属火，咸属水故为心家对宫之药），其善清心热，原有专长，故无大便燥结证而亦加
之也。用甘草者，所以缓药力之下行，且又善调胃也。不用朴、实者，因无大便燥结及腹满之证也。
承气汤虽有三方，而小承气及调胃承气，实自大承气变化而出。《伤寒论》所载三承气主治之证不胜录，
然果洞悉三方之各有用意，及三方药力轻重各有区别，且所主之病虽有上、中、下之分，而究之治上可及于
中，治中可及于下，分治之中，仍有连带关系，自能凡遇宜用承气汤证，斟酌其宜轻宜重，分别施治而无差谬矣。
至于愚用承气汤之经过，又恒变化多端，不拘拘于三承气汤中之药味也。今试举数案以征明之。
大承气汤所主之证，原宜脉迟，其有脉不迟而洪实有力者，
亦不妨用。惟其脉不迟而转数，若因大便燥结，而遽投以大承气汤，其脉之无力者，恒因大便通后而虚脱。
其脉之有力者，下后纵不至虚脱，其病亦必不能愈，所谓降后不解也。凡遇此等脉，必设法将其脉数治愈，
然后再通其大便。
曾治一叟，年近六旬，因外感之热过甚，致大便旬日未通，其脉数逾六至，心中烦热，延医数人，皆不
敢用降下之剂，然除降下外，又别无治法。愚诊其脉象虽数，重按甚实，遂先投以大剂白虎加人参汤，每
剂分三次温服下，连服两剂，壮热全消，脉已不数，大便犹未通下，继用净芒硝细末三钱，蜂蜜一两，开水
冲服，大便通下，病遂愈。
曾治一少年，因外感实热，致大便燥结，旬余未下，其脉亦数逾六至，且不任重按，亦投以白虎加人
参汤，以生地黄代方中知母，生山药代方中粳米，煎汤一大碗，俾分多次徐徐温饮下。初服一剂，脉数见缓，
遂即原方略为减轻，俾再煎服，拟后服至脉象复常，再为通其大便，孰意次剂服完而大便自通下矣。且大
使通下后，外感之实热亦消解无余矣。此直以白虎加人参汤代承气汤也，自治愈此病之后，凡遇有证之可下而
可缓下者，恒以白虎汤代承气，或以白虎加人参汤代承气，其凉润下达之力，恒可
使大便徐化其燥结，无事用承气而自然通下，且下后又无不解之虞也。
治一少妇，于大怒之余感冒伤寒，热传阳明，大便燥结，医者两次投以大承气皆吐出。诊其脉弦长有力，
盖脉现弦长，无论见于何部，皆主肝火炽盛，此不受药之所以然也。遂于大承气汤中将朴、实减轻（
朴实各用钱半），加生杭芍、生赭石各一两，临服药时，又恐药汤入口即吐出，先用白开水送服生赭石细末
三钱，继将药服下，阅三点钟大便通下而病即愈矣。
又治一人素伤烟色，平日大便七八日一行，今因受外感实
热，十六七日大便犹未通下，心中烦热，腹中胀满，用洗肠法下燥粪少许，而胀满烦热如旧，医者谓其气
虚脉弱，不敢投降下之药。及愚诊之，知其脉虽弱而火则甚实，遂用调胃承气汤加野台参四钱，生赭石、天门
冬各八钱，共煎汤一大碗，分三次徐徐温饮下，饮至两次，腹中作响，觉有开通之意，三次遂不敢服，迟
两点钟大便通下，内热全消，霍然愈矣。
有服承气汤后，大便之燥结不下，继服些许他药而燥结始下者，试再举两案以明之。
邑中名医刘××，愚初学医时，家中常延之，一日，见先生治一伤寒热入阳明大便燥结证，从前医者，
投以大承气汤两剂不下，继延先生治之，单用威灵仙三钱，煎汤服后大便通下，病亦遂愈。愚疑而问曰∶威
灵仙虽能通利二便，以较硝、黄攻下之力实远不如，乃从前服大承气汤两剂大便不下，何先生只用威灵
仙三钱而大便即下乎？答曰∶其中原有妙理，乃前后所用之药相借以成功也。盖其从前所服之大承气汤两剂，
犹在腹中，因其脏腑之气化偶滞，药力亦随之停顿，借威灵仙走窜之力以触发之，则硝、黄力之停顿者，可陡
呈其开通攻决之本性，是以大便遂通下也。是威灵仙之于硝、黄，犹如枪炮家导火之线也。愚闻如此妙
论，顿觉心地开通，大有会悟，后有仿此医案之时，亦随手奏效。
因并录之于此，由此知医学虽贵自悟，亦必启发之有自也。
邻村霍××，当怒动肝火之余感受伤寒，七八日间腹中胀满，大便燥结，医者投以大承气汤，大便未
通下，肋下转觉疼不可支。其脉左部沉弦有力，知系肝经气郁火盛，急用柴胡三钱，生麦芽一两，煎汤服后，
至半点钟肋下已不觉疼，又迟一点余钟，大便即通下。大便下后，腹即不胀，而病脱然全愈矣。
此案实仿前案之义，亦前后药力相借以通大便也。盖肾为二
便之关，肝行肾之气，肝又主疏泄，大便之通与不通，实于肝有
关系也。调其肝郁，即可以通行大便，此中原有至理。至于调肝用柴胡而又必佐以生麦芽者，因麦芽生用亦
善调肝者也。且柴胡之调肝，在于升提，生麦芽之调肝，在于宣通，若因肝不舒但用柴胡以升提之，恐初服
下时肋下之疼将益剧。惟柴胡之升提，与麦芽之宣通相济以成调肝气之功，则肝气之郁者自开，遏者自
舒，而徐还其疏泄之常矣。且柴胡之性不但善调肝气也，《神农本草经》谓柴胡主心腹肠胃中结气，饮
食积聚，寒热邪气，推陈致新。三复《神农本草经》之文，是柴胡不但善于调肝，兼能消胀满通大便矣。然
柴胡非降下之药也，其于大便之当通者，能助硝黄以通之，若遇脾胃之气下溜大便泄泻者，伍以 、术转能
升举脾胃之气以止泄泻，柴胡诚妙药也哉。善于用柴胡者，自能深悟此中之妙理也。
至于妊妇外感热实，大便燥结者，承气汤亦不妨用，《内经》所谓“有故无殒亦无殒也”。然此中须有斟
白虎汤和白虎加人参汤这两个方子，都是治疗足阳明经有实热的。当热邪传入手阳明大肠腑，导致大便因热而燥结时，燥结越严重，蕴蓄的热邪就越深，如果不破除燥结，热邪是肯定无法消除的。像这种情况，攻下的药剂，如承气汤等方剂就是必不可少的了。
《伤寒论》原文记载：阳明病，脉象迟缓，虽然出汗但不怕冷，身体必然沉重，气短，腹部胀满且喘息，如果有潮热现象，说明表证已解，可以攻里了。如果手足濈然汗出，这说明大便已经坚硬，应用大承气汤主治。如果汗出很多，伴有轻微发热和怕冷，说明表证未解，其热势没有潮热特点，不可给予承气汤。如果腹部显著胀满且不通畅，可以给予小承气汤，轻微调和胃气，不要让它剧烈泻下。
首句提到阳明病脉迟，这是表明阳明病脉迟是可以攻下的第一个明确征象。起初我理解这句话的意思，认为凡是伤寒阳明病应当攻下的，如果脉数，攻下后往往不能痊愈，这里说脉迟，未必比正常脉象更慢，只是表明脉不数，不用担心攻下后病不解罢了。等到阅历丰富后，才知道阳明病需要攻下时，脉象原本就有迟的情况。然而这种脉迟并不是迟缓之象，而是像积蓄到了极点突然通畅，呈现出一种迟而突出的脉象。大概是因为肠道中有阻塞导致脉迟。脉迟却能突出，是因为阳明火盛，脉原本有力，有东西阻碍了脉的力量使其变迟，这恰恰激发了脉的力量使其产生跳跃之势。这样解释脉迟，那么脉迟应当攻下的道理自然就明白了。
然而我临证实践以来，知道阳明病既然应当攻下，脉迟的可以攻下，即使脉不迟也不数的，也可以攻下。只有脉数及一息六至（脉搏极快）时才不可攻下，如果强行攻下，病一定不解，或者病情更加严重。而我对于这类证候，原本就有变通的攻下法，即使用白虎加人参汤，将石膏不煎入汤中，而是用煎好的药汤送服石膏粉。我因为屡次用此方奏效，于是命名为白虎承气汤，详细记录如下，以备医学界采用。
生石膏八钱（捣细），大潞党参三钱，知母八钱，甘草二钱，粳米二钱。药物共五味，将后四味煎取汤液一盅半，分两次用温药汤送服生石膏细末。服用第一次药后，过两小时，如果腹中没有动静，再服第二次。如果腹中已有动静，再过半小时大便已下的，停止后续服药。如果仍未下，再将第二次药服下。至于脉虽数但洪滑有力的，用此方时也可以不加党参。
我以前遇到寒温病应当攻下而脉象数的，常投以大剂量白虎汤，或白虎加人参汤，大便也能通下。但是生石膏必须用到四五两，煎一大碗，分几次温服，大便才能通下。间或有服几剂后大便仍不通的，其人通常脉净身凉，少用玄明粉二三钱和蜜冲服，大便即可通下。然而终究不如白虎承气汤用起来方便。
生石膏如果服用研细的粉末，其退热力量一钱可抵煎汤者半两。如果用来通便，一钱可抵煎汤者一两。所以方中只用生石膏八钱，而又慎重使用，必须分两次服下。
寒温病阳明病，热势极盛的，投以大剂量白虎汤，热势稍退，第二天常常病状依旧。如此反复数次，病人家属便怀疑药不对症，转而延请其他医生，因此导致病重难愈的情况很多。我后来拟定这个方子，凡遇到投以白虎汤见效后又反复的，再次治疗时就直接用石膏为末送服。汤剂中如果用五六两石膏，送服的粉末不过一两，最多一两半，热势即可全消。
【大承气汤方】大黄四两（酒洗），浓朴半斤（炙去皮），枳实五枚（炙），芒硝三合。
以上四味，用水一斗，先煮前二味（厚朴、枳实），取五升，去渣，纳大黄，煮取二升，去渣，纳芒硝，再上微火煮一二沸，分两次温服，得下（大便通下），余药勿服。
大承气汤的作用，是用来通利肠道中因热导致的燥结。所以以大黄性善攻下且善泻热为主药。然而药力的运行必须依靠脏腑的气化来斡旋，所以佐以厚朴、枳实来流通肠道中郁塞的气化，那么大黄的攻下就容易发挥作用了。用芒硝，是取其性寒味咸，善清热又善软坚，且兼有攻下之力，那么坚结的燥粪不难化为溏粪而通下。方中的用意如此，药味不多，确实能面面俱到精妙周到，但我对这个方子并非没有可疑之处，那就是药味分量的轻重问题。
《神农本草经》说大黄能推陈致新，所以有“黄良”的名号，在阳明蕴有实热大便燥结的情况下，原本宜多用。至于厚朴不过是作为大黄的辅佐品，竟然重用至半斤，比大黄的量加倍，如果按一两折合现在的三钱计算，又分两次服用，那么一次所服的药，当有厚朴一两二钱。夫厚朴气温味辛，如果多用，能损伤人的真气，这是人所共知的，而且它的性能又能横行达表，发出人的热汗。回忆我年轻时，曾治一个阳明实热大便燥结的病例，方中用大黄三钱，服后大便未通，改延请其他医生，方中重用厚朴一两，服后半晌遍体出热汗，似喘非喘，气弱不足以呼吸，不到半天就死亡了。这确实可以作为前车之鉴。所以我谓此方的分量必有差误，我怀疑此方厚朴的分量，应当也像小承气汤那样是大黄分量的一半，其原本或许是“厚朴之分量半大黄”，大抵是由这个“半”字误写为“半斤”吧。
再者，本节原文以“阳明病脉迟”五字开端，所谓脉迟，是说其脉象虽有热象但至数不加数（并非指比平脉更慢）。这是病人身体素壮，阴分尤其充足的脉象。病候到了需要用大承气汤的时候，果能有如此脉象，投以大承气汤原方，也可以随手奏效。而现在的大承气汤证出现这种脉象的，实在不多见。这既是关天时，也是关人事，实为古今不同之处。即令厚朴的分量原本是这样，医者也应当随时制宜为之通变化裁，才可以成为善于师法张仲景的人。不然的话，其脉或不迟而数，只用硝、黄降之，还恐怕降后病不解，因为阴虚不能胜其燥热啊，何况更重用厚朴来增加其燥热呢？又或者其脉纵不数，而热实脉虚，只用硝、黄降之，还恐怕降后发生下脱，因为其气分原亏，不堪硝、黄的推荡啊，何况敢重用厚朴同枳实来破其气呢？昔日叶天士用药催生，曾加梧桐叶一片作引，有有效的，反而被叶天士嘲笑。有人问他原因，叶天士说：“我用的梧桐叶一片时，那天是立秋，取梧桐一叶落之意。如果不是那个时令，还用梧桐叶做什么？”由此可知名医治病，莫不因时制宜，原本就不是胶柱鼓瑟（不知变通）的。所以我用承气汤时，大黄、芒硝常常都用至七八钱，厚朴、枳实用不过二钱。或者仿照调胃承气汤的意义，都减去不用，外加生赭石细末五六钱，其攻下之力不减大承气原方，而较诸原方用起来实在稳妥得多。至于脉象数的，及脉象虽热而重按无力的，又常先投以大剂量白虎加人参汤，煎汤一大碗，分几次温饮下，以化胃中燥热，而由胃及肠即可润其燥结，往往有服完未终剂，大便即通下的。而且下后又无虞其不解，更无虑其下脱。其间有大便未即通下的，可用玄明粉三钱，或西药硫酸镁四钱，调以蜂蜜，开水冲服。或外治用猪胆汁导法，或用食盐（若用熬火硝所出的盐更佳）融水灌肠，皆可通下。至通下之后，无不痊愈的。
【小承气汤方】大黄四两（酒洗），厚朴二两（炙去皮），枳实三枚大者（炙）。
以上三味，用水四升，煮取一升二合，去渣，分两次温服。初服汤后应当排便，如果不排便，则喝完所有药液。如果排便了，就不要服剩下的药。
大承气汤所主的病，是大肠中有燥粪，所以用芒硝软坚以化其燥粪。小承气汤所主的病是腹部显著胀满不通，是其病在于小肠而上连于胃，所以只用大黄、厚朴以开通其小肠，小肠开通下行，大便不必通下，即使通下也不会太多，而胃中的食物可下输于小肠，所以胃气得和。这就是大、小承气汤用法上的区别。而在二承气汤之外，又有调胃承气汤，更可连类论及。
【调胃承气汤方】大黄四两（去皮清酒浸），甘草二两（炙），芒硝半升。
以上三味（注：原文此处写“上二味”有误，实为三味，或指大黄甘草先煎），切碎，用水三升，煮取一升，去渣，纳芒硝，再上火微煮令沸，少量多次温服。
大黄虽然是攻下的药品，原本善清血分之热，心中发烦实为血分有热。大黄浸以清酒，可引其苦寒之性上行以清心之热而烦可除。证无大便燥结而仍用芒硝的，《内经》说热淫于内治以咸寒。芒硝味咸性寒，实为心家对宫之药（心属火，咸属水故为心家对宫之药），其善清心热，原有专长，所以无大便燥结证也加上它。用甘草，是为了缓药力之下行，且又善调胃。不用厚朴、枳实，是因为无大便燥结及腹满之证。
承气汤虽有三方，而小承气及调胃承气，实自大承气变化而出。《伤寒论》所载三承气主治之证不胜枚举，但如果果真洞悉三方各有用意，及三方药力轻重各有区别，且所主之病虽有上、中、下之分，而究其实际治上可及于中，治中可及于下，分治之中，仍有连带关系，自然能凡遇宜用承气汤证，斟酌其宜轻宜重，分别施治而无差错。至于我用承气汤的过程，又常常变化多端，不拘泥于三承气汤中的药味。现在试举几案以证明。
大承气汤所主的证，原本宜脉迟，其有脉不迟而洪实有力的，也不妨用。惟其脉不迟而转数，如果因大便燥结，就遽然投以大承气汤，其脉之无力者，常因大便通后而虚脱。其脉之有力者，下后纵不至虚脱，病也必不能愈，所谓降后不解。凡遇此类脉，必设法将其脉数治愈，然后再通其大便。
曾治一位老人，年近六旬，因外感之热过甚，致大便旬日未通，其脉数逾六至，心中烦热，延医数人，都不敢用降下之剂，然而除降下外，又别无治法。我诊其脉象虽数，重按甚实，遂先投以大剂量白虎加人参汤，每剂分三次温服下，连服两剂，壮热全消，脉已不数，大便犹未通下，继用净芒硝细末三钱，蜂蜜一两，开水冲服，大便通下，病遂愈。
曾治一位少年，因外感实热，致大便燥结，旬余未下，其脉亦数逾六至，且不任重按，也投以白虎加人参汤，以生地黄代方中知母，生山药代方中粳米，煎汤一大碗，让分多次徐徐温饮下。初服一剂，脉数见缓，随即原方略为减轻，让其再煎服，拟后服至脉象复常，再为通其大便，孰料次剂服完而大便自通下了。且大便通下后，外感之实热亦消解无余矣。这简直是以白虎加人参汤代替承气汤，自治愈此病之后，凡遇有证可下而可缓下的，常以白虎汤代承气，或以白虎加人参汤代承气，其凉润下达之力，常可使大便徐化其燥结，无事用承气而自然通下，且下后又无不解的忧虑。
治一位少妇，于大怒之余感冒伤寒，热传阳明，大便燥结，医者两次投以大承气皆吐出。诊其脉弦长有力，盖脉现弦长，无论见于何部，皆主肝火炽盛，此不受药的原因所在。遂于大承气汤中将厚朴、枳实减轻（各用钱半），加生杭芍、生赭石各一两，临服药时，又恐药汤入口即吐出，先用白开水送服生赭石细末三钱，继将药服下，阅三点钟大便通下而病即愈矣。
又治一人素伤烟色，平日大便七八日一行，今因受外感实热，十六七日大便犹未通下，心中烦热，腹中胀满，用洗肠法下燥粪少许，而胀满烦热如旧，医者谓其气虚脉弱，不敢投降下之药。到我诊之，知其脉虽弱而火则甚实，遂用调胃承气汤加野台参四钱，生赭石、天门冬各八钱，共煎汤一大碗，分三次徐徐温饮下，饮至两次，腹中作响，觉有开通之意，三次遂不敢服，迟两点钟大便通下，内热全消，霍然愈矣。
有服承气汤后，大便之燥结不下，继服些许他药而燥结始下的，试再举两案以明之。
邑中名医刘某某，我初学医时，家中常延请他。一日，见先生治一伤寒热入阳明大便燥结证，从前医者，投以大承气汤两剂不下，继延先生治之，单用威灵仙三钱，煎汤服后大便通下，病亦遂愈。我疑而问曰：威灵仙虽能通利二便，以较硝、黄攻下之力实远不如，乃从前服大承气汤两剂大便不下，何先生只用威灵仙三钱而大便即下乎？答曰：其中原有妙理，乃前后所用之药相借以成功也。盖其从前所服之大承气汤两剂，犹在腹中，因其脏腑之气化偶滞，药力亦随之停顿，借威灵仙走窜之力以触发之，则硝、黄力之停顿者，可陡呈其开通攻决之本性，是以大便遂通下也。是威灵仙之于硝、黄，犹如枪炮家导火之线也。我闻如此妙论，顿觉心地开通，大有会悟，后有仿此医案之时，亦随手奏效。
并录于此，由此知医学虽贵自悟，亦必启发之有自也。
邻村霍某某，当怒动肝火之余感受伤寒，七八日间腹中胀满，大便燥结，医者投以大承气汤，大便未通下，肋下转觉疼不可支。其脉左部沉弦有力，知系肝经气郁火盛，急用柴胡三钱，生麦芽一两，煎汤服后，至半点钟肋下已不觉疼，又迟一点余钟，大便即通下。大便下后，腹即不胀，而病脱然全愈矣。
此案实仿前案之义，亦前后药力相借以通大便也。盖肾为二便之关，肝行肾之气，肝又主疏泄，大便之通与不通，实于肝有关系也。调其肝郁，即可以通行大便，此中原有至理。至于调肝用柴胡而又必佐以生麦芽者，因麦芽生用亦善调肝者也。且柴胡之调肝，在于升提，生麦芽之调肝，在于宣通，若因肝不舒但用柴胡以升提之，恐初服下时肋下之疼将益剧。惟柴胡之升提，与麦芽之宣通相济以成调肝气之功，则肝气之郁者自开，遏者自舒，而徐还其疏泄之常矣。且柴胡之性不但善调肝气也，《神农本草经》谓柴胡主心腹肠胃中结气，饮食积聚，寒热邪气，推陈致新。三复《神农本草经》之文，是柴胡不但善于调肝，兼能消胀满通大便矣。然柴胡非降下之药也，其于大便之当通者，能助硝黄以通之，若遇脾胃之气下溜大便泄泻者，伍以人参、白术转能升举脾胃之气以止泄泻，柴胡诚妙药也哉。善于用柴胡者，自能深悟此中之妙理也。
至于妊妇外感热实，大便燥结者，承气汤亦不妨用，《内经》所谓“有故无殒亦无殒也”。然此中须有斟
Both the Baihu Tang (White Tiger Decoction) and Baihu Jia Renshen Tang (White Tiger plus Ginseng Decoction) are used to treat excess heat in the Foot-Yangming channel. When heat enters the Fu-organ of the Hand-Yangming (Large Intestine), causing dryness and constipation of the stool due to heat, the more severe the dryness and constipation, the deeper the accumulated heat. In such cases, unless the dryness and constipation are opened up, the heat certainly cannot be eliminated. Therefore, purgative agents, such as the Chengqi Tang formulas, are essential.
Original text from *Shanghan Lun* (Treatise on Cold Damage): "In Yangming disease, if the pulse is slow, although there is sweating and no aversion to cold, the body will feel heavy, there will be shortness of breath, abdominal fullness, and wheezing. If there is tidal fever, it indicates that the exterior syndrome has resolved, and interior attack is permissible. If there is continuous sweating on the hands and feet, this indicates that the stool has become hard; Dachengqi Tang (Major Order the Qi Decoction) should be administered. If there is profuse sweating with slight fever and aversion to cold, the exterior pathogen has not yet resolved, and the heat is not tidal; Chengqi Tang should not be given. If there is significant abdominal fullness and obstruction, Xiaochengqi Tang (Minor Order the Qi Decoction) may be given to mildly harmonize the Stomach Qi, avoiding drastic purgation."
The first sentence mentions "Yangming disease with a slow pulse," which is the first clear sign indicating that Yangming disease with a slow pulse warrants purgation. Initially, I interpreted this sentence to mean that for all Shanghan (Cold Damage) Yangming cases requiring purgation, if the pulse is rapid, purgation often fails to resolve the condition. Thus, mentioning a slow pulse here does not necessarily mean slower than a normal pulse, but rather indicates the absence of rapidity, ensuring one need not worry about the failure of purgation afterward. However, after extensive clinical experience, I realized that Yangming diseases requiring purgation can indeed present with a slow pulse. Yet, this slowness is not merely sluggish; it resembles a state where accumulation reaches its peak before breaking through, presenting a pulse that is slow yet prominent. This slowness is caused by obstruction in the intestines. The fact that the slow pulse becomes prominent is because Yangming fire is flourishing, and the pulse is originally forceful; something obstructs the force of the pulse, making it slow, which precisely激ates (stimulates/excites) the pulse's force, creating a jumping sensation. Explaining the slow pulse in this way makes the rationale for purging based on a slow pulse self-evident.
However, since my clinical practice, I have known that when Yangming disease requires purgation, a slow pulse definitely permits purgation, and even if the pulse is neither slow nor rapid, purgation is also permissible. Only when the pulse is rapid or beats six times per respiration (extremely rapid) should purgation be avoided. Forcing purgation in such cases will certainly fail to resolve the disease or exacerbate it. For such syndromes, I originally devised an alternative purgative method: using Baihu Jia Renshen Tang, but not decocting the Shigao (Gypsum Fibrosum) into the soup. Instead, the fine powder of Shigao is taken with the warm decoction of the other herbs. Having used this formula successfully many times, I named it Baihu Chengqi Tang (White Tiger Order the Qi Decoction) and recorded it below for reference by the medical community.
Raw Gypsum Fibrosum (Shigao) 8 qian (crushed finely), Large Lu Dangshen (Codonopsis Radix) 3 qian, Tianmum (Anemarrhenae Rhizoma) 8 qian, Gancao (Licorice Root) 2 qian, Jingmi (Rice Grain) 2 qian. These five ingredients: decoct the last four in water to obtain 1.5 bowls of liquid. Take the fine powder of Raw Gypsum Fibrosum with warm herbal liquid in two doses. After the first dose, wait two hours. If there is no movement in the abdomen, take the second dose. If there is already movement in the abdomen, wait another half hour; if stool passes, stop further medication. If stool has not passed, take the second dose again. If the pulse is rapid but surging, slippery, and forceful, Dangshen may be omitted from this formula.
Previously, when encountering exogenous febrile diseases requiring purgation with a rapid pulse, I often prescribed large doses of Baihu Tang or Baihu Jia Renshen Tang, which could also facilitate bowel movement. However, Raw Gypsum Fibrosum had to be used in doses of 4-5 liang, decocted into a large bowl, and taken in divided warm doses for the stool to pass. Occasionally, after several doses, if the stool still did not pass, the patient would typically have a clean pulse and cool body temperature. Using a small amount of Xuanmingfen (Mirabilite) 2-3 qian mixed with honey and taken with boiled water could induce defecation. Nevertheless, this is not as convenient as using Baihu Chengqi Tang.
If Raw Gypsum Fibrosum is taken as a fine powder, its heat-clearing efficacy of 1 qian equals that of 0.5 liang when decocted. To promote bowel movement, 1 qian of powder equals 1 liang of decoction. Therefore, this formula uses only 8 qian of Raw Gypsum Fibrosum, administered cautiously in two divided doses.
In exogenous febrile diseases involving Yangming, when heat is extremely intense, prescribing large doses of Baihu Tang may reduce the heat slightly, but the next day the illness often returns to its original state. After repeating this several times, patients' families may suspect the medicine is incorrect and seek other doctors, leading to severe or fatal outcomes. Later, I formulated this prescription. Whenever Baihu Tang showed initial effect followed by recurrence, I would use Gypsum powder taken with the decoction during subsequent treatments. If the decoction contained 5-6 liang of Gypsum, the powder taken would be only 1 liang, at most 1.5 liang, and the heat would completely dissipate.
[Dachengqi Tang Formula] Dahuang (Rhubarb Root) 4 liang (washed with wine), Houpo (Magnolia Bark) 0.5 jin (roasted, skin removed), Zhishi (Immature Bitter Orange) 5 pieces (roasted), Mangxiao (Mirabilite) 3 he.
Take the above four ingredients, add 10 dou of water, first decoct the first two (Houpo and Zhishi), reduce to 5 sheng, remove dregs, add Dahuang, decoct to 2 sheng, remove dregs, add Mangxiao, boil gently for one or two boils, divide into two warm doses. If defecation occurs, do not take the remainder.
Dachengqi Tang is designed to unblock dryness and constipation in the intestines caused by heat. Therefore, Dahuang, which is good at purging and clearing heat, serves as the principal herb. However, the action of medicinal power relies on the qi transformation of the Zang-Fu organs to maneuver it. Thus, Houpo and Zhishi are added as assistants to circulate the stagnant qi transformation in the intestines, facilitating Dahuang's purgative action. Mangxiao is used for its cold nature and salty taste, which clears heat, softens hardness, and possesses purgative properties, making it easy to transform hard dry stool into loose stool for passage. The intent of this formula is thus: few ingredients, yet comprehensive and precise. However, I have doubts about this formula, specifically regarding the weight of the ingredients.
*Shennong Bencao Jing* states that Dahuang can push out the old and bring forth the new, hence its name "Huangliang" (Excellent Yellow). In Yangming conditions with excess heat and dry constipation, it is originally appropriate to use a larger dose. Houpo, however, is merely an assistant to Dahuang, yet it is heavily used at 0.5 jin, double the dose of Dahuang. Converting 1 liang to approximately 3 qian today, and dividing into two doses, each dose would contain about 1.2 liang (approx. 3.6 qian) of Houpo. Houpo is warm in nature and pungent in taste; excessive use damages true Qi, which is common knowledge. Its nature also allows it to spread outward to the surface, inducing hot sweating. I recall treating a case of Yangming excess heat with dry constipation in my youth. The formula used 3 qian of Dahuang, but the stool did not pass. Another doctor was consulted, who used 1 liang of Houpo. Shortly after taking it, the patient sweated profusely with hot sweat all over the body, appeared to pant but did not, had weak Qi insufficient for breathing, and died within half a day. This serves as a warning. Therefore, I believe the dosages in this formula must be erroneous. I suspect the dosage of Houpo should be half that of Dahuang, similar to Xiaochengqi Tang. The original text might have said "Houpo's dosage is half of Dahuang," which was mistakenly written as "half jin" (ban jin) instead of "half" (ban).
Furthermore, the section begins with "Yangming disease, slow pulse." Here, "slow pulse" means the pulse rate is not increased despite the presence of heat (not necessarily slower than a normal pulse). This indicates a patient who is physically robust with abundant Yin. If such a pulse appears when Dachengqi Tang is indicated, administering the original formula can be effective. However, such pulses are rarely seen in modern Dachengqi Tang cases. This difference is due to both timing and human factors, marking a distinction between ancient and modern times. Even if the original Houpo dosage was correct, physicians must adapt according to circumstances to truly follow Zhang Zhongjing. Otherwise, if the pulse is not slow but rapid, using only Xiao (Mirabilite) and Huang (Rhubarb) to purge might fail to resolve the disease due to Yin deficiency failing to overcome dryness-heat. How much more so would using heavy Houpo increase dryness-heat? Or if the pulse is not rapid but the heat is excess while the pulse is deficient, using only Xiao and Huang might lead to collapse after purging because the Qi is originally deficient and cannot withstand the pushing action of Xiao and Huang. How dare one use heavy Houpo and Zhishi to break the Qi? Ye Tianshi once added a parasol tree leaf to induce labor, which worked, but he mocked it. When asked why, he said, "I used one leaf on the day of Start of Autumn, symbolizing 'one leaf falls.' If it were not that time, what would be the purpose of using a parasol tree leaf?" Thus, famous doctors treat diseases by adapting to time and circumstances, never rigidly sticking to fixed rules. Therefore, when I use Chengqi Tang, I often use Dahuang and Mangxiao in doses of 7-8 qian, while Houpo and Zhishi are used only in 2 qian. Or, following the principle of Weitiao Chengqi Tang, I omit them entirely and add 5-6 qian of fine powder of Shizhe Shi (Ochre Hematite). This maintains the purgative power of Dachengqi Tang but is much safer. For rapid pulses, or pulses that feel hot but are weak upon deep pressure, I often first prescribe large doses of Baihu Jia Renshen Tang, decocted into a large bowl, taken in divided warm sips to clear dryness-heat in the Stomach. Moisture then moves from the Stomach to the Intestines, resolving dryness. Often, defecation occurs before the course is finished. Moreover, there is no fear of unresolved disease or collapse after purging. If defecation does not occur immediately, Xuanmingfen 3 qian or Magnesium Sulfate 4 qian can be mixed with honey and taken with boiled water. Alternatively, external treatment with pig bile enema, or salt water enema (salt derived from firing saltpeter is better) can induce defecation. After defecation, recovery is assured.
[Xiaochengqi Tang Formula] Dahuang 4 liang (wine-washed), Houpo 2 liang (roasted, skin removed), Zhishi 3 large pieces (roasted).
Take the above three ingredients, add 4 sheng of water, decoct to 1.2 sheng, remove dregs, divide into two warm doses. After the first dose, if bowel movement occurs, do not take the rest. If not, drink the entire amount.
Dachengqi Tang treats dry feces in the Large Intestine, hence Mangxiao is used to soften hardness. Xiaochengqi Tang treats significant abdominal fullness and obstruction, indicating the pathology lies in the Small Intestine extending to the Stomach. Therefore, only Dahuang and Houpo are used to open the Small Intestine. Once the Small Intestine opens and descends, defecation is not strictly necessary, and if it occurs, it will not be excessive. Food in the Stomach can descend to the Small Intestine, harmonizing Stomach Qi. This distinguishes the usage of Da and Xiao Chengqi Tangs. Additionally, Weitiao Chengqi Tang (Harmonize the Stomach Order the Qi Decoction) is discussed alongside these.
[Weitiao Chengqi Tang Formula] Dahuang 4 liang (skin removed, soaked in clear wine), Gancao 2 liang (roasted), Mangxiao 0.5 sheng.
Chop the ingredients, add 3 sheng of water, decoct to 1 sheng, remove dregs, add Mangxiao, boil gently until boiling, take in small warm doses.
Although Dahuang is a purgative, it is good at clearing heat from the Blood level. Irritability in the heart indicates Heat in the Blood. Soaking Dahuang in clear wine guides its bitter-cold nature upward to clear Heart Heat and relieve irritability. Mangxiao is used even without dry constipation because *Neijing* states: "For heat rampant inside, treat with salty-cold." Mangxiao is salty and cold, acting as the "opposite palace" of the Heart (Heart belongs to Fire, Salt belongs to Water). It excels at clearing Heart Heat. Gancao is used to slow the downward action of the drugs and harmonize the Stomach. Houpo and Zhishi are omitted because there is no dry constipation or abdominal fullness.
Although there are three Chengqi Tang formulas, Xiaochengqi and Weitiao Chengqi are variations of Dachengqi Tang. *Shanghan Lun* lists many indications for these three, but understanding their distinct intents and varying strengths allows one to treat upper, middle, and lower aspects appropriately. Treating the upper can affect the middle, and the middle can affect the lower; they are interconnected. Thus, one can judiciously choose the appropriate strength for Chengqi Tang indications without error. My use of Chengqi Tang is often flexible and not limited to these three formulas. I will cite several cases to demonstrate.
Dachengqi Tang is indicated for slow pulses, but can also be used for surging, solid, and forceful pulses. However, if the pulse is not slow but rapid, and one hastily prescribes Dachengqi Tang for dry constipation, patients with weak pulses risk collapse after defecation. Those with strong pulses may not collapse, but the disease will not resolve ("purge but not resolved"). For such pulses, one must first cure the rapidity before promoting defecation.
Case 1: An elderly man, nearly sixty, suffered from severe exogenous heat causing ten days of constipation. His pulse beat more than six times per respiration, with irritability and heat in the chest. Several doctors dared not use purgatives, having no other options. I found his pulse rapid but very solid upon deep pressure. I first prescribed large doses of Baihu Jia Renshen Tang, taken in three divided warm doses. After two doses, high fever subsided, and the pulse was no longer rapid, but stool remained impacted. I then gave 3 qian of pure Mangxiao powder mixed with 1 liang of honey in boiled water. Defecation occurred, and the disease resolved.
Case 2: A young man suffered from exogenous excess heat causing dry constipation for over ten days. His pulse was rapid (>6 beats/respiration) and weak upon deep pressure. I prescribed Baihu Jia Renshen Tang, substituting Shengdihuang (Rehmanniae Radix) for Tianmu and Shengshanyao (Dioscoreae Rhizoma) for Jingmi. Decocted into a large bowl, taken in multiple small warm sips. After one dose, the rapid pulse slowed. I reduced the dose slightly and continued. I intended to continue until the pulse normalized before purging. Unexpectedly, after the second dose, defecation occurred spontaneously. The exogenous excess heat also completely dissipated. This effectively substituted Baihu Jia Renshen Tang for Chengqi Tang. Since curing this case, whenever a purgative indication exists but can be treated gently, I often substitute Baihu Tang or Baihu Jia Renshen Tang for Chengqi Tang. Their cooling, moistening, and descending power often slowly resolves dryness, allowing natural defecation without Chengqi Tang, eliminating fears of unresolved disease or collapse.
Case 3: A young woman contracted Cold Damage after extreme anger. Heat transmitted to Yangming, causing dry constipation. Two prescriptions of Dachengqi Tang were vomited up. Her pulse was wiry, long, and forceful. A wiry-long pulse indicates blazing Liver Fire regardless of location, explaining the rejection of the medicine. I reduced Houpo and Zhishi in Dachengqi Tang (to 1.5 qian each), added 1 liang of Shengbaishao (Paeoniae Radix Alba) and 1 liang of Shizhe Shi (Ochre Hematite). Before taking the decoction, she took 3 qian of Shizhe Shi powder with plain water to prevent vomiting. Three hours later, defecation occurred, and she recovered.
Case 4: A person habitually damaged by smoking and sexual indulgence usually had bowel movements every 7-8 days. Due to exogenous excess heat, he had not defecated for 16-17 days, with irritability and abdominal fullness. Enema expelled some dry stool, but symptoms persisted. Doctors cited Qi deficiency and weak pulse, fearing purgatives. I found his pulse weak but fire excessive. I prescribed Weitiao Chengqi Tang plus Yetaishen (Wild Codonopsis) 4 qian, Shizhe Shi 8 qian, and Tiandong (Asparagi Radix) 8 qian. Decocted into a large bowl, taken in three warm sips. After two sips, the abdomen rumbled, indicating opening. He stopped after the third sip. Two hours later, defecation occurred, internal heat vanished, and he recovered instantly.
Two more cases illustrate situations where defecation occurred only after taking other medicines following failed Chengqi Tang attempts.
Famous local doctor Liu XX: When I was learning medicine, he often visited my home. One day, I saw him treating a case of Cold Damage with heat entering Yangming and dry constipation. Previous doctors had given two doses of Dachengqi Tang without success. Dr. Liu prescribed only 3 qian of Weilingxian (Syringae Ramulus) decocted in water. Defecation occurred, and the disease resolved. I asked: Weilingxian can promote urination and defecation, but its purgative power is far inferior to Xiao and Huang. Why did 3 qian work where Dachengqi Tang failed? He replied: There is subtle logic. The previous two doses of Dachengqi Tang remained in the abdomen. Due to temporary stagnation of Zang-Fu Qi transformation, the drug power paused. Weilingxian's penetrating power triggered this stored power, causing the stalled Xiao and Huang to suddenly exhibit their purgative nature, leading to defecation. Weilingxian acts like a fuse for Xiao and Huang. Hearing this profound theory, I gained great insight and successfully applied this method subsequently.
Huox XX from a neighboring village: Contracted Cold Damage after anger-induced Liver Fire. Abdominal fullness and dry constipation for 7-8 days. Dachengqi Tang failed to induce defecation, causing unbearable pain in the hypochondrium. Left pulse was deep, wiry, and forceless, indicating Liver Qi stagnation and fire excess. I urgently prescribed 3 qian Chaihu (Bupleuri Radix) and 1 liang ShengMaiya (Hordei Fructus Germinatus). Decocted and taken. Half an hour later, hypochondriac pain ceased. Over an hour later, defecation occurred. Abdominal fullness disappeared, and the disease resolved completely.
This case follows the previous logic, borrowing power from prior medications. The Kidney governs the gate of the two excretions. The Liver moves Kidney Qi and governs dispersion. Bowel movement depends on the Liver. Regulating Liver stagnation promotes defecation. Chaihu regulates the Liver by ascending, while ShengMaiya regulates by dispersing and unblocking. Using only Chaihu might worsen hypochondriac pain initially. Together, they harmonize Liver Qi, opening stagnation and restoring dispersion. *Shennong Bencao Jing* states Chaihu treats knotting Qi in the heart, abdomen, and intestines, food accumulation, and alternating chills and fever, pushing out the old and bringing forth the new. Repeated reading confirms Chaihu not only regulates the Liver but also reduces fullness and promotes defecation. Although Chaihu is not a descending purgative, it assists Xiao and Huang in promoting defecation. Conversely, in cases of Spleen-Stomach Qi sinking with diarrhea, combined with Renshen and Baizhu, it lifts Spleen-Stomach Qi to stop diarrhea. Chaihu is indeed a miraculous herb. Those skilled in using it deeply understand its subtleties.
For pregnant women with exogenous excess heat and dry constipation, Chengqi Tang can be used, as stated in *Neijing*: "If there is a cause, there is no harm." However, careful judgment is required...