禹余粮，味甘，气寒，无毒。入脾、胃、大肠。疗血闭瘕症，止赤白漏下，除寒热烦满、
咳
逆邪伤。经曰∶重可去怯。禹余粮之重，正镇固之剂，可用之止滑也。但只可暂用以固脱，
不可久服以延年。《本经》言耐老轻身，予不敢信。
或问禹余粮，传大禹治水之时，弃粮于山中，乃成此物，故凶荒之时，可掘而服食以救
饥，
果有之乎？曰∶此好事者之言也。禹余粮乃山中之土，异于凡土则有之，岂能疗饥以活命。
夫饥馑之民，肠胃未有不虚弱者也。用禹余粮之重物以充饥，非充饥也。正所以速之死耳。
吕仙曰∶远公注《本草》，悯禹余粮之不可救荒，请命于我。我嘉远公善心之无穷也，传一
法以救饥。遇凶荒之年，朝东方日出时，心中注定于太阳，不必朝对太阳也，用口开吸太阳
之气，自觉为我吞入，咽下腹中一口，口中漱津一口，咽送腹中，如此七次，不必再咽。但
饮滚水、食青草，再不死矣。此救饥之妙法也，特志之。
石膏，味辛、甘，气大寒，体重而沉降也。阴中之阳，无毒。生用为佳，火 不灵。入
肺、
胃、三焦。能出汗解肌，上理头痛，缓脾止渴。风邪伤阳，寒邪伤阴，皆能解肌表而愈。胃
热多食，胃热不食，唯泻胃火而痊。祛痰火之
积，止胃脘之痛，发狂可安，谵语可定，乃降火之神剂，泻热之圣药也。仲景张
夫子以白虎名之，明示人以不可轻用，而非教人之不用也。乃世人畏之真如白虎，竟至不敢
一用，又何以逢死症而重生，遇危症而重安哉。夫石膏降火，乃降胃火，而非降脏火也；石
膏泻热，乃泻真热，而非泻假热也。辨其胃火真热，用石膏自必无差。而胃火初起之时，口
必作渴，呼水饮之必少快，其汗必如雨，舌必大峭，虽饮水而口必燥，眼必红，神必不安。
如见此等之症，确是胃火而非脏火，即可用石膏而不必顾忌。而真热者，舌必生刺，即不生
刺，舌苔必黄而有裂纹，大渴呼饮，饮水至十余碗而不足，轻则谵语，大则骂詈，见水而入
，弃衣而走，登高而呼，发狂不知人，此真热也，即可用石膏大剂灌之，不必疑虑。倘或口
虽渴而不甚，与之水而不饮，言语虽胡乱而不骂詈，身虽热而不躁动，上身虽畏热而下体甚
寒，皆假热之症，即不可轻用石膏矣。以此辨火热，万不至杀人，奚必畏之如虎，看其死而
不救也。盖石膏实救死之药，因看症不清，遂至用药有误，救死之药反变为伤生之药矣。今
既辨之明，自必用之确也。
或问用石膏以治真正胃火，单用石膏可矣，何以张仲景先生必加入人参、麦冬者乎？曰∶
胃
火之盛者，胃土之衰也。泻胃火，未有不伤胃土者也。伤胃土，必伤胃气矣。加人参于石膏
汤中，非助胃火，乃顾胃土也。胃土不伤，则胃气不丧，似乎可罔顾肺气矣。然而胃火升腾
，必伤肺金，用人参以顾胃，而不用麦冬以养肺，则胃子必救肺金之母，以泄胃气，则胃气
仍损，虽用人参，犹之无用也。（〔批〕顾胃土，顾肺金，阐义实精。）故又加麦冬，同人参
并用，以助石膏之泻火，火泻而肺金有养，不耗气于胃土，则胃气更加有养。此所以既用石
膏，而又加人参，既用人参，而又加麦冬也。
或问石膏泻胃火，又加知母以泻肾火，何为耶？盖胃火太盛，烁干肾水。用石膏以泻胃
火者
，实所以救肾水也。然而，胃火既烁肾水，肾水若干，相火必然助胃火以升腾矣，胃火得相
火而益烈。单泻胃火，而相火不退，则胃火有源，未易扑灭，愈加其焰矣。泻胃火，而即泻
相火，则胃火失党，其火易散，大雨滂沱，而龙雷不兴，其炎热之威自然速解。此所以用石
膏以泻胃中之火者，必用知母以泻肾中之火也。（〔批〕泻肾火，正所以泻胃火，妙论出奇
。）
或疑石膏既泻胃火，又用知母以泻肾火，用麦冬以安肺火，宜乎火之速退而热之尽解矣，
何
以用白虎汤往往有更甚者？曰∶嗟乎。此又非白虎汤之故，乃不善用白虎汤之故也。火势不
同，有燎原之火，有燃烧之火。燃烧之火，其势已衰；燎原之火，其势正炽。以救燃烧者救
燎原，势必愈为扑灭，而愈增其光焰矣。人身之胃火亦不同，有轻有重。轻者，如燃烧之火
，少用白虎汤，即可解其热；重者，如燎原之火，非多用白虎汤，不足以灭其氛。倘以治轻
者治重，安得不添其火势之焰天乎，非变为亡阳，即变为发狂矣。
或疑石膏比为白虎，明是杀人之物，教人慎用之宜也。今又云火重者，非多用石膏不可，
吾
恐又启天下轻用石膏之祸，未必非救人而反害人也。曰∶嗟乎。论症不可不全，论药不可不
备，天下有此症候，即宜论此治法。乌可因石膏之猛，避其杀人之威，而不彰其生人之益乎
。石膏实有功过，总在看症之分明，不在石膏之多寡。若看症之误，多用固杀人，而少用亦
未尝不杀人。若看症之确，少用固救人。而多用亦未尝不救人。然则人亦辨症可也，何必忌
用石膏哉。
或又疑石膏可多用以救人之生，先生不宜从前之过虑矣，毕竟石膏宜少用而不宜多用也。
曰
∶石膏原不宜多用。石膏大寒，戒多用者，乃论其常；胃火大旺，戒少用者，乃论其变。存
不可多用之心，庶不至轻投以丧命；存不宜少用之心，庶不至固执以亡躯。知不宜多用，而
后可多用以出奇，庶几变死为生，反危为安也。
或疑石膏泻燎原之火，自宜多用以泻火矣，然而过多又恐伤胃，若何而使胃不伤，火又
即熄
之为快乎？曰∶燎原之火，即生于地上，胃中之火，即起于土中。以石膏而救其胃中之火，
即如用水而救其燎原之火也。然而，燎原之火以水救之，而无伤于地；胃中之火以石膏救之
，必有伤于土。盖土即胃土也，胃土非火不能生，奈何反用水以灭之乎？然而胃火之盛，非
胃中之真火盛，乃胃中之邪火盛也。邪火，非水不可灭，故不得已大用石膏，以泻其一时之
火也。又胃火之盛，乃胃土之衰也，胃火既盛，而胃土愈衰，胃土既衰，复用寒凉以泻火，
火衰而胃土更衰矣。故泻火之中，即宜补土之为急，倘徒泻其火，未有不土崩者矣。治法宜
人参同用于石膏之中，大约用石膏十之七者，人参用十之三，相济而相施。火既易熄，而胃
土又不伤，断无有亡阳之祸者也。（〔批〕用石膏以泻火，即用人参以救土，实妙论妙法也
。）
或疑石膏泻胃火，有用至一两，而仍不解，几几有发狂之变，又将何药以解之乎？曰∶
舍石
膏，再无别法也。夫发狂之病，此胃火热极，不可以常法治者也，必须用石膏至二三两，加
人参亦必二三两。又不可拘于前说，用石膏十之七，而人参用十之三也。（〔批〕知常知变
，才见起死回生手段。）盖火盛之极者，土衰之极也，不用
人参以补元气，而唯用石膏以救其火炎，未有不败者也。此等之病，必登高而歌，弃衣而走
，见水而入，大骂大叫，神欲外越，此呼吸存亡之秋，不得不以变法治之。倘服前药而少安
，便有生机，否则，虽多用石膏、人参，亦何以救之哉。
或疑发狂之病，往往有少用石膏，多用人参而愈者，又是何故？曰∶发狂有虚火、邪火
之不
同。邪火之发
狂，必须多用石膏、人参，以挽回于俄顷。虚火之发狂，又宜专用人参，以定乱于须臾。岂
特石膏必宜少用，且断断不可共用也。苟虚实、邪正之不明，而用药一错，未有不下喉即杀
人者。而虚实、邪正，何以辨之，要不能舍验舌之法，而另求辨症也。正虚而发狂者神乱，
而舌必润滑；邪实而发狂者神越，而舌必红黄，且燥极而开裂纹也。以此辨症，又何误乎。
或疑石膏定狂，定胃中之火也，何以即能定心中之狂乎？不知心中之狂，乃起于胃中之
火也
。救胃火，正所以救心狂也。夫心乃火脏，胃火宜非所畏。乃胃火热而心发狂者，如本是同
舟之人，一时劫夺，变出非常。苟不诛讨，则心宫何安乎，此救狂必泻火也。
或疑寒凉之药多能杀人者，无过石膏，即黄柏、知母，亦不同其类。屏黄柏、知母而不
弃石
膏，何也？曰∶石膏，乃救死之药也。胃火热极，非石膏不能降。胃火不降，必变发狂而死
矣，用石膏救之，死症立变为生。彼用石膏而杀人者，非胃火而妄用之也。夫人身之火，最
烈者，胃火与肾火也。胃火宜泻，而肾火宜补。不用石膏以泻胃火，而反用石膏以泻肾火，
安得而不杀人乎。但肾火与胃火补泻之不同，乃宜补而用泻，亦因黄柏、知母降肾火之说而
误之也。寒凉之药，未尝不生人，彼误用之而杀人，与石膏何过乎。
或又疑屏黄柏、知母之并用，是知母不可助寒凉以杀人矣，先生偏称知母助石膏能生人，
抑
又何也？曰∶胃火之盛，原宜直降胃火，用石膏，不宜再用知母。然而胃火之所以盛，由于
肾水之衰，水虚而不能制火也。胃火既盛，势必烁干肾水，水尽而火势焰天，人即立亡矣。
用石膏以泻胃火者，正所以急救肾水也。但徒救肾水，而肾火增热，势必胃火仍旺，而不遽
熄。故又用知母，以暂退其肾中之火，则胃火无党，庶几易于扑灭也。此石膏必用知母之相
助，乃一时权宜之计，而非永久之图也。
或问石膏能泻胃火，胃火既泻，何必又用知母？先生偏誉知母助石膏之有功，似亦偏说
也。
曰∶石膏泻胃火以救肾水，不能泻胃火以泻肾火也。胃为肾之关门，胃火息而肾火犹盛，是
关门路平烽熄，而内火焚烧，岂是安宁之象。故泻胃火，即宜泻肾火也，泻肾火，非知母不
可，尤妙知母不唯止泻肾火，且能泻胃火，所以同石膏用之，则彼此同心，顾肾即能顾胃，
不比黄柏专泻肾而不泻胃也。
或问白虎汤发明真无微不晰，而石膏用之于大、小青龙汤中，尚未议及，岂白虎能杀人，
而
青龙否乎？曰∶龙性难驯，用之不当，其杀人同于白虎。夫同一石膏也，何以分称龙、虎，
亦在人用之何如耳。用之于热散之中，则名青龙；用之于寒散之中，则名白虎。石膏大凉，
用于热之内，则能解热，而不畏其凉；用于寒之内，过于大凉，虽能退热，而常生其变。似
乎白虎之汤，猛于青龙也。然而，邪在胃，非白虎不可解热；邪未入胃而将入于胃，非青龙
不可解热也。惟是石膏得桂枝、麻黄，势善升腾，用之青龙汤中，只可少而不可多，有异于
白虎汤中，石膏可以重加也。
或问青龙汤有大、小之名，分在石膏之多寡乎？曰∶石膏不可多用，不独小青龙汤也。
小青
龙之别于大青龙者，以方中用芍药也。龙性虽难驯，得芍药之酸收，则石膏不能升腾矣，盖
芍药所以制石膏也。譬如小龙初长头角，惟恐伤人，畏首畏尾，故以小名之。世人但知石膏
之猛，谁知加入芍药，则石膏正无足忌乎。惟小青龙之用石膏，不得其宜，亦有祸害，但不
若大青龙无制之横耳。
又问大青龙既然过横，何不加入芍药乎？曰∶此又不可也。邪在荣卫之间，将趋入于阳
明，
非大青龙之急用，断不能行雨以散热。若加入芍药之酸收，则风云不能际会，未免收敛有余
，而优渥不足。此仲景夫子特制大青龙汤，雨以沛之，毋单尚凉风之习习也。
禹余粮，味道甘甜，性质寒凉，没有毒性。进入脾、胃、大肠经。治疗血闭和瘕症（腹内结块），止住赤白带下，消除寒热交替、心烦胀满、咳嗽气逆及邪气损伤。医经说：“重镇之药可以去除怯懦。”禹余粮质地沉重，正是具有镇固作用的药物，可以用来止住滑脱之症。但只能暂时用来固摄脱证，不可长期服用以求延年益寿。《神农本草经》说它能使人耐寒耐老、身体轻健，我不敢相信。
有人问：禹余粮，传说是大禹治水时，把粮食丢弃在山中，才形成了这种物质，所以在饥荒之年，可以挖掘出来食用以救饥饿，真的有这样的事吗？回答说：这是好事者编造的话。禹余粮是山中的泥土，虽然不同于普通的泥土，但怎么能充饥救命呢？那些遭受饥荒的百姓，肠胃没有不虚弱的。用禹余粮这样沉重的东西来充饥，并不是在充饥，恰恰是加速他们的死亡罢了。吕洞宾仙人说：远公注释《本草》，怜悯禹余粮不能用于救灾，向我请示。我赞赏远公无尽的善心，传授给他一个救饥的方法。遇到饥荒之年，在早晨东方日出时，心中意念专注于太阳，不必正对着太阳，用口吸入太阳之气，自觉像是吞入腹中一口，口中再漱津液一口，咽送腹中，如此重复七次，不需要再吞咽。只要喝开水、吃青草，就不会死了。这是救饥的妙法，特意记录下来。
石膏，味道辛、甘，性质大寒，体重而沉降。属于阴中之阳，没有毒性。生用效果最佳，火煅则药效不灵。进入肺、胃、三焦经。能够发汗解肌，上治头痛，缓和脾气、止渴。风邪伤阳，寒邪伤阴，都能解除肌表之邪而痊愈。胃热导致多食，或胃热导致不食，只有清泻胃火才能痊愈。祛除痰火的积聚，止住胃脘疼痛，发狂可以安神，胡言乱语可以定志，是降火的特效药剂，泻热的圣药。张仲景先生以“白虎”命名它，明确告诉人们不可轻易使用，而不是教人不用。然而世人畏惧它真像畏惧白虎一样，竟然不敢使用，那又怎能逢死症而复活，遇危症而转安呢？石膏降火，是降胃火，而不是降脏腑之火；石膏泻热，是泻真热，而不是泻假热。辨别出是胃火真热，使用石膏自然不会有差错。而在胃火初起之时，口必定作渴，呼叫喝水会稍微感到爽快，出汗必定如雨，舌头必定干裂，即使喝水嘴巴也必定干燥，眼睛必定发红，神志必定不安。如果看到这些症状，确是胃火而非脏火，就可以使用石膏而不必顾忌。而真正的热症，舌头必定生出芒刺，即使不生芒刺，舌苔必定黄而有裂纹，极度口渴呼叫饮水，喝水多达十余碗仍觉不足，轻则胡言乱语，重则骂詈叫号，见到水就跳进去，扔掉衣服奔跑，登高呼喊，发狂不知人事，这是真热症，就可以大量灌服石膏，不必疑虑。倘若口虽渴但不严重，给水却不喝，言语虽胡乱但不骂詈，身体虽热但不躁动，上身虽怕热而下体非常寒冷，都是假热症，就不可轻易使用石膏了。以此辨别火热，万不至于杀人，何必像怕老虎一样畏惧它，看着人死而不救呢？大概石膏实际上是救死的药，因为辨证不清，导致用药有误，救死的药反而变成了害人的药了。现在既然辨析得清楚，自然使用得准确。
有人问：用石膏治疗真正的胃火，单用石膏就可以了，为什么张仲景先生一定要加入人参、麦冬呢？回答说：胃火旺盛的人，往往是胃土虚弱。清泻胃火，没有不损伤胃土的。损伤胃土，必然损伤胃气。在石膏汤中加入人参，不是为了助长胃火，而是为了顾护胃土。胃土不受伤，胃气就不丧失，似乎可以不顾及肺气了。然而胃火升腾，必然会损伤肺金，用人参来顾护胃，而不用麦冬来滋养肺，那么胃子（指胃气）必然会求助于肺金之母（按五行理论，火为土之母，此处逻辑稍显复杂，意指通过补土生金或相关关系），从而耗泄胃气，那么胃气仍然受损，虽然用了人参，也如同没用一样。（〔批注〕顾护胃土，顾护肺金，阐发的义理确实精妙。）所以又加入麦冬，与人参同用，以辅助石膏泻火，火被泻去而肺金得到滋养，不在胃土上耗气，那么胃气就更加得到滋养。这就是为什么既用石膏，又加人参；既用人参，又加麦冬的原因。
有人问：石膏泻胃火，又加入知母以泻肾火，为什么呢？大概是因为胃火太盛，烧干了肾水。用石膏来泻胃火，实际上是为了救肾水。然而，胃火既然烧灼肾水，肾水一旦干枯，相火必然助长胃火使其升腾，胃火得到相火的帮助更加猛烈。单纯泻胃火，而相火不退，那么胃火就有源头，不容易扑灭，反而更加炽烈。泻胃火的同时即泻相火，那么胃火失去党羽，火势容易消散，就像大雨滂沱，龙雷之火不会兴起，其炎热的威势自然迅速解除。这就是为什么用石膏泻胃中之火，必须用知母泻肾中之火的原因。（〔批注〕泻肾火，正是为了泻胃火，奇妙的论述出奇制胜。）
有人怀疑：石膏既泻胃火，又用知母泻肾火，用麦冬安肺火，火应该迅速消退而热完全解除了，为什么用白虎汤往往病情反而加重？回答说：唉！这又不是白虎汤的过错，是不善于使用白虎汤的过错。火势不同，有燎原之火，有燃烧之火。燃烧之火，其势头已经衰弱；燎原之火，其势头正炽盛。用救治燃烧之火的方法来救治燎原之火，势必越扑灭，光焰越增加。人身上的胃火也不同，有轻有重。轻的，像燃烧之火，少用白虎汤，就可以解除其热；重的，像燎原之火，不多用白虎汤，不足以熄灭其气势。如果用治轻症的方法治重症，怎么能不增添火势冲天呢？不是变成亡阳，就是变成发狂了。
有人怀疑：将石膏比作白虎，明明是杀人的东西，教导人们慎用是合适的。现在又说火重的，非多用石膏不可，我担心这会开启天下人轻用石膏的祸患，未必不是救人反而害人。回答说：唉！论症不可不全，论药不可不备，天下有这样的症候，就应该讨论这种治法。怎么能因为石膏猛烈，避开它杀人的威势，而不彰显它救人的益处呢？石膏确实有功有过，总在于辨证是否分明，不在于石膏用量的多少。如果辨证错误，多用固然杀人，少用也未尝不杀人。如果辨证确切，少用固然救人，多用也未尝不救人。既然如此，人们只要辨证即可，何必忌讳使用石膏呢？
有人又怀疑：石膏可以多用以救人之生，先生不应该从前那样过度忧虑了，毕竟石膏宜少用而不宜多用。回答说：石膏原本不宜多用。石膏大寒，告诫不要多用，是论述其常理；胃火大旺，告诫不要少用，是论述其变通。存有不可多用的心念，才不会轻率投药丧命；存有不宜少用的心念，才不会固执己见亡身。知道不宜多用，然后才可以多用以出奇制胜，差不多能将死转为生，反危为安。
有人怀疑：石膏泻燎原之火，自然应该多用以泻火，然而过多又恐怕伤胃，怎样能使胃不受伤，火又立即熄灭才好呢？回答说：燎原之火，产生于地上；胃中之火，产生于土中。用石膏来救胃中之火，就像用水来救燎原之火。然而，燎原之火用水救，而不伤土地；胃中之火用石膏救，必然伤土。盖土即胃土，胃土非火不能生长，怎么反而用水来灭它呢？然而胃火之盛，不是胃中的真火盛，而是胃中的邪火盛。邪火，非水不可灭，所以不得已大用石膏，以泻其一时的火。又胃火之盛，乃是胃土之衰，胃火既盛，胃土愈衰，胃土既衰，再用寒凉药泻火，火衰而胃土更衰了。所以在泻火之中，应当以补土为急务，如果只泻其火，没有不土崩瓦解的。治法宜将人参同用于石膏之中，大约用石膏十分之七，人参用十分之三，相互济助施用。火既容易熄灭，而胃土又不受伤，断不会有亡阳的祸患。（〔批注〕用石膏泻火，即用人参救土，实在是妙论妙法。）
有人怀疑：石膏泻胃火，有用到一两，仍然不解，几乎有发狂的变化，又将用什么药来解救呢？回答说：舍去石膏，再无别法。夫发狂的病，这是胃火热极，不可以常规法治，必须用石膏至二三两，加入人参也必用二三两。又不可拘泥于前说，用石膏十分之七，而人参用十分之三。（〔批注〕知常知变，才见得起死回生的手段。）大概火盛到极点，就是土衰到极点，不用人参来补元气，而只用石膏来救其火炎，没有不败坏的。这种病，必定登高而歌，弃衣而走，见水而入，大骂大叫，神志欲外越，这是呼吸间存亡的关键时刻，不得不以变法治疗。倘若服前面的药稍微安定，便有生机，否则，虽然多用石膏、人参，又怎么能救活呢？
有人怀疑：发狂的病，往往有少用石膏，多用人参而痊愈的，又是什么原因？回答说：发狂有虚火、邪火的不同。邪火引起的发狂，必须多用石膏、人参，以在短时间内挽回局面。虚火引起的发狂，又宜专用人参，以在短时间内安定混乱。岂止石膏必宜少用，而且绝对不可共用。如果虚实、邪正不明确，而用药一错，没有不喝下去就杀人的。而虚实、邪正，如何辨别，关键在于不能舍弃验舌的方法，而另求辨证。正气虚而发狂者神乱，而舌头必定润滑；邪气实而发狂者神越，而舌头必定红黄，且干燥至极而开裂纹。以此辨证，又有什么错误呢？
有人怀疑：石膏定狂，是定胃中之火，为什么就能定心中之狂呢？不知道心中之狂，乃起于胃中之火。救胃火，正是为了救心狂。夫心是火脏，胃火本不应畏惧。然而胃火热而心发狂者，如同本是同舟之人，一时劫夺，变出非常之事。如果不诛讨，心宫怎么安宁呢？此救狂必泻火。
有人怀疑：寒凉的药物多能杀人，没有超过石膏的，即黄柏、知母，也与石膏不同类。摒弃黄柏、知母而不弃石膏，为什么呢？回答说：石膏，是救死的药。胃火热极，非石膏不能降。胃火不降，必变发狂而死，用石膏救之，死症立刻变为生。那些用石膏杀人的，不是胃火而妄用之。人身上的火，最猛烈的是胃火与肾火。胃火宜泻，而肾火宜补。不用石膏以泻胃火，反而用石膏以泻肾火，怎么能不杀人呢？但肾火与胃火补泻的不同，乃是因为宜补而用泻，也是因黄柏、知母降肾火的说法而误用的。寒凉的药物，未尝不能生人，那些误用它们杀人的，与石膏有什么过错呢？
有人又怀疑：摒弃黄柏、知母的并用，是知母不可助寒凉以杀人了，先生偏偏称赞知母助石膏能生人，又是为什么呢？回答说：胃火之盛，原本宜直降胃火，用石膏，不宜再用知母。然而胃火之所以盛，由于肾水之衰，水虚而不能制火。胃火既盛，势必烧干肾水，水尽而火势焰天，人即立亡。用石膏以泻胃火，正是为了急救肾水。但徒救肾水，而肾火增热，势必胃火仍旺，而不迅速熄灭。所以又用知母，以暂时退却其肾中之火，则胃火无党羽，庶几易于扑灭。此石膏必用知母之相助，乃是一时权宜之计，而非永久之图谋。
有人问：石膏能泻胃火，胃火既泻，何必又用知母？先生偏偏赞誉知母助石膏之功，似亦偏颇之说。回答说：石膏泻胃火以救肾水，不能泻胃火以泻肾火。胃为肾之关门，胃火息而肾火犹盛，是关门路平烽熄，而内火焚烧，岂是安宁之象。故泻胃火，即宜泻肾火，泻肾火，非知母不可，尤妙知母不唯止泻肾火，且能泻胃火，所以同石膏用之，则彼此同心，顾肾即能顾胃，不比黄柏专泻肾而不泻胃。
有人问：白虎汤发明得真无微不晰，而石膏用之于大、小青龙汤中，尚未议及，难道白虎能杀人，而青龙否乎？回答说：龙性难驯，用之不当，其杀人同于白虎。夫同一石膏也，何以分称龙、虎，亦在人用之何如耳。用之于热散之中，则名青龙；用之于寒散之中，则名白虎。石膏大凉，用于热之内，则能解热，而不畏其凉；用于寒之内，过于大凉，虽能退热，而常生其变。似乎白虎之汤，猛于青龙也。然而，邪在胃，非白虎不可解热；邪未入胃而将入于胃，非青龙不可解热也。惟是石膏得桂枝、麻黄，势善升腾，用之青龙汤中，只可少而不可多，有异于白虎汤中，石膏可以重加也。
有人问：青龙汤有大、小之名，分在石膏之多寡乎？回答说：石膏不可多用，不独小青龙汤也。小青龙之别于大青龙者，以方中用芍药也。龙性虽难驯，得芍药之酸收，则石膏不能升腾矣，盖芍药所以制石膏也。譬如小龙初长头角，惟恐伤人，畏首畏尾，故以小名之。世人但知石膏之猛，谁知加入芍药，则石膏正无足忌乎。惟小青龙之用石膏，不得其宜，亦有祸害，但不若大青龙无制之横耳。
又问：大青龙既然过横，何不加入芍药乎？回答说：此又不可也。邪在荣卫之间，将趋入于阳明，非大青龙之急用，断不能行雨以散热。若加入芍药之酸收，则风云不能际会，未免收敛有余，而优渥不足。此仲景夫子特制大青龙汤，雨以沛之，毋单尚凉风之习习也。
Yu Yuliang (Hematitum), sweet in taste, cold in nature, non-toxic. Enters the Spleen, Stomach, and Large Intestine meridians. Treats blood obstruction and mass disorders (abdominal masses), stops red and white leukorrhea, eliminates alternating chills and fever, mental restlessness, fullness, cough, rebellious Qi, and pathogenic damage. The Classics state: "Heavy substances can dispel timidity." Yu Yuliang is heavy in quality, precisely a sedative and consolidating agent, usable to stop sliding and leakage. However, it should only be used temporarily to consolidate collapse, and not taken for a long time to prolong life. The *Shennong Bencao Jing* states it enables one to endure old age and lightens the body; I dare not believe this.
Someone asked: Yu Yuliang, it is said that during Da Yu's control of the waters, he discarded grain in the mountains, which then became this substance. Therefore, during times of famine, it can be dug up and eaten to save hunger. Is this true? I replied: This is the talk of busybodies. Yu Yuliang is earth from the mountains; while different from ordinary soil, how can it fill the stomach and save lives? People suffering from famine invariably have weak spleens and stomachs. Using the heavy substance of Yu Yuliang to fill the stomach is not filling the stomach; it is precisely accelerating death. Immortal Lu Dongbin said: Yuan Gong annotated the *Bencao*, pitying that Yu Yuliang could not be used for disaster relief, and sought my advice. I appreciated Yuan Gong's endless kindness and transmitted a method to save lives. In years of famine, at dawn when the sun rises in the east, focus your mind on the sun; you do not need to face the sun directly. Inhale the Qi of the sun with your mouth, as if swallowing it into your abdomen. Then rinse saliva in your mouth and swallow it into your abdomen. Repeat this seven times, no need to swallow more. Just drink boiling water and eat green grass, and you will not die. This is a wonderful method for saving lives from famine, recorded here specially.
Shigao (Gypsum Fibrosum), pungent and sweet in taste, extremely cold in nature, heavy and descending. It belongs to Yang within Yin, non-toxic. Raw use is best; calcined use lacks efficacy. Enters the Lung, Stomach, and San Jiao meridians. It can induce sweating and release the muscle layer, treat headache upwards, soothe the Spleen, and stop thirst. Whether Wind Pathogen damages Yang or Cold Pathogen damages Yin, both can be resolved by releasing the exterior. For excessive eating due to Stomach Heat, or lack of appetite due to Stomach Heat, only by purging Stomach Fire can recovery occur. It removes accumulations of phlegm-fire, stops epigastric pain, calms mania, and stabilizes delirium; it is a divine agent for descending fire and a holy medicine for purging heat. Master Zhang Zhongjing named it "White Tiger," clearly indicating to people that it should not be used lightly, rather than teaching people not to use it at all. Yet people fear it truly like a White Tiger, daring not to use it even once. How then can they revive from critical conditions and find safety in dangerous situations? Shigao descends fire, but it descends Stomach Fire, not Zang organ fire; Shigao purges heat, but it purges True Heat, not False Heat. If one distinguishes Stomach Fire and True Heat, using Shigao will certainly be without error. At the initial stage of Stomach Fire, the mouth must feel thirsty, calling for water brings slight relief, sweat must be like rain, the tongue must be dry and cracked, even after drinking water the mouth remains dry, eyes must be red, and spirit must be restless. If these symptoms are seen, confirming Stomach Fire rather than Zang Fire, Shigao can be used without hesitation. For True Heat, the tongue must have prickles; even if no prickles, the coating must be yellow with cracks, extreme thirst calling for drinking, consuming over ten bowls of water still insufficient, mild cases involve delirium, severe cases involve cursing, jumping into water upon seeing it, running naked, climbing high and shouting, mania with loss of consciousness—this is True Heat, and large doses of Shigao can be administered without doubt. If, however, the mouth is thirsty but not severely so, refuses water when offered, speech is confused but not abusive, body is hot but not restless, upper body fears heat but lower body is very cold, these are all False Heat symptoms, and Shigao should not be used lightly. By distinguishing fire and heat thus, one will never kill people; why fear it like a tiger and watch people die without helping? Essentially, Shigao is a medicine that saves lives; because of unclear differentiation, medication errors occurred, turning a life-saving medicine into a life-taking one. Now that differentiation is clear, usage will surely be accurate.
Someone asked: To treat genuine Stomach Fire with Shigao, single use of Shigao suffices; why did Mr. Zhang Zhongjing insist on adding Renshen (Ginseng) and Maidong (Ophiopogon)? I replied: Excessive Stomach Fire indicates deficiency of Stomach Earth. Purging Stomach Fire inevitably injures Stomach Earth. Injuring Stomach Earth inevitably injures Stomach Qi. Adding Renshen to the Shigao decoction does not aid Stomach Fire, but protects Stomach Earth. If Stomach Earth is not injured, Stomach Qi is not lost, seemingly allowing one to disregard Lung Qi. However, rising Stomach Fire inevitably damages Lung Metal. Using Renshen to protect the Stomach but not Maidong to nourish the Lung means the Stomach will seek its mother (Lung Metal is the child of Stomach Earth in some contexts, or referring to mutual generation/support dynamics where imbalance affects others), depleting Stomach Qi, so Stomach Qi remains damaged. Even with Renshen, it is as if unused. ([Commentary] Protecting Stomach Earth and Lung Metal elucidates profound principles.) Thus, Maidong is added, used together with Renshen, to assist Shigao in purging fire. Once fire is purged and Lung Metal is nourished, Qi is not consumed from Stomach Earth, thereby further nourishing Stomach Qi. This is why Shigao is used, plus Renshen; and Renshen is used, plus Maidong.
Someone asked: Shigao purges Stomach Fire, yet adds Zhimu (Anemarrhena) to purge Kidney Fire. Why? Presumably because excessive Stomach Fire scorches Kidney Water. Using Shigao to purge Stomach Fire is actually to save Kidney Water. However, since Stomach Fire scorches Kidney Water, once Kidney Water is dry, Ministerial Fire (Xiang Huo) will inevitably assist Stomach Fire in rising, making Stomach Fire more fierce with the help of Ministerial Fire. Solely purging Stomach Fire while Ministerial Fire remains unextinguished means Stomach Fire has a source and is hard to extinguish, increasing its flame. Purging Stomach Fire while simultaneously purging Ministerial Fire means Stomach Fire loses its allies, and the fire easily scatters, like heavy rain preventing Dragon Thunder from rising, naturally resolving the intense heat quickly. This is why Shigao is used to purge Middle Jiao Fire, and Zhimu is necessary to purge Kidney Fire. ([Commentary] Purging Kidney Fire is precisely to purge Stomach Fire; a brilliant and unexpected argument.)
Someone doubts: Shigao purges Stomach Fire, Zhimu purges Kidney Fire, Maidong calms Lung Fire; fire should retreat quickly and heat resolve completely. Why does Baihu Tang often result in worsening conditions? I replied: Alas! This is not the fault of Baihu Tang, but the fault of not using Baihu Tang skillfully. Fire patterns differ: there is prairie-fire and burning-fire. Burning-fire has already weakened; prairie-fire is currently blazing. Using methods for burning-fire to treat prairie-fire will inevitably increase the flames. Stomach Fire in the human body also varies, being light or heavy. Light cases, like burning-fire, require little Baihu Tang to resolve heat; heavy cases, like prairie-fire, require much Baihu Tang to extinguish the momentum. If treating heavy cases with light-case methods, how can one not add to the sky-high fire? It will either become Yang collapse or mania.
Someone doubts: Comparing Shigao to the White Tiger implies it is a killing object, teaching caution is appropriate. Now saying heavy fire requires much Shigao, I fear this will open the disaster of casual Shigao use nationwide, potentially harming rather than saving people. I replied: Alas! Differentiation must be comprehensive, and drug properties fully discussed. Where such symptoms exist, such treatments must be discussed. How can one avoid its killing potential due to Shigao's potency and fail to highlight its life-saving benefits? Shigao indeed has merits and faults, depending entirely on clear differentiation, not on dosage. If differentiation is wrong, much kills, and little may also kill. If differentiation is correct, little saves, and much may also save. Thus, people should differentiate symptoms; why fear using Shigao?
Someone again doubts: Since Shigao can be used in large amounts to save lives, the master should not have worried excessively before; ultimately, Shigao should be used in small amounts, not large. I replied: Shigao originally should not be used in large amounts. Shigao is extremely cold; warning against large doses discusses the norm. Warning against small doses for massive Stomach Fire discusses the variation. Keeping the mindset that it should not be used in large amounts prevents casual administration leading to death; keeping the mindset that it should not be used in small amounts prevents stubbornness leading to demise. Knowing it should not be used in large amounts allows for large doses to achieve extraordinary results, turning death to life and danger to safety.
Someone doubts: Shigao purges prairie-fire, so naturally it should be used in large amounts. However, too much might injure the Stomach. How to ensure the Stomach is not injured while the fire is extinguished quickly? I replied: Prairie-fire arises from the ground; Stomach Fire arises from the Earth (Stomach). Using Shigao to save Stomach Fire is like using water to save prairie-fire. However, water saves prairie-fire without injuring the land; Shigao saves Stomach Fire but inevitably injures Earth. Earth refers to Stomach Earth; Stomach Earth cannot grow without Fire, so how can one use water to extinguish it? However, excessive Stomach Fire is not due to excessive True Fire in the Stomach, but excessive Evil Fire. Evil Fire cannot be extinguished without water; thus, reluctantly using large amounts of Shigao to purge temporary fire. Furthermore, excessive Stomach Fire indicates deficiency of Stomach Earth. As Stomach Fire increases, Stomach Earth declines; as Stomach Earth declines, using cold/cool drugs to purge fire further declines Stomach Earth. Therefore, amidst purging fire, tonifying Earth is urgent. If only purging fire, collapse is inevitable. Treatment should include Renshen with Shigao, roughly 70% Shigao and 30% Renshen, mutually assisting. Fire extinguishes easily, Stomach Earth is not injured, and Yang collapse will certainly not occur. ([Commentary] Using Shigao to purge fire while using Renshen to save Earth is truly a brilliant theory and method.)
Someone doubts: Shigao purges Stomach Fire; even using one tael fails to resolve it, approaching mania. What medicine can resolve this? I replied: Apart from Shigao, there is no other method. Mania caused by extreme Stomach Fire cannot be treated by routine methods. One must use two to three taels of Shigao, adding two to three taels of Renshen. One must not stick to the previous ratio of 70% Shigao to 30% Renshen. ([Commentary] Knowing the constant and the variable reveals the ability to revive the dead.) Extreme fire excess indicates extreme Earth deficiency. Without Renshen to tonify Original Qi, relying solely on Shigao to rescue flaming fire will inevitably fail. Such patients climb high singing, run discarding clothes, jump into water, curse loudly, spirit欲 leaving the body. This is a critical moment of life and death, requiring variable treatment. If previous medicines bring slight peace, there is hope; otherwise, even large doses of Shigao and Renshen cannot save them.
Someone doubts: Mania cases often recover with little Shigao and much Renshen. Why? I replied: Mania differs between Deficient Fire and Evil Fire. Evil Fire mania requires much Shigao and Renshen to salvage the situation instantly. Deficient Fire mania requires exclusive use of Renshen to stabilize chaos instantly. Not only should Shigao be used sparingly, but it absolutely should not be co-administered. If Deficiency/Excess and Righteous/Evil are unclear, and medication is mistaken, death follows immediately upon ingestion. How to distinguish Deficiency/Excess and Righteous/Evil? One cannot abandon tongue diagnosis to seek differentiation. Righteous Deficiency causing mania involves chaotic spirit and a moist tongue; Evil Excess causing mania involves protruding spirit and a red-yellow, extremely dry, cracked tongue. With this differentiation, how can one err?
Someone doubts: Shigao calms mania by calming Stomach Fire; how can it calm Heart mania? I replied: Heart mania originates from Stomach Fire. Saving Stomach Fire is precisely saving Heart mania. The Heart is a Fire organ; Stomach Fire should not be feared. However, when Stomach Fire causes Heart mania, it is like companions hijacking each other, creating abnormal events. If not punished, how can the Heart Palace be safe? Thus, calming mania requires purging fire.
Someone doubts: Cold/cool drugs often kill; none exceed Shigao. Huangbai (Phellodendron) and Zhimu are different categories. Why discard Huangbai and Zhimu but not Shigao? I replied: Shigao is a life-saving medicine. Extreme Stomach Fire cannot be descended except by Shigao. If Stomach Fire is not descended, it turns to mania and death; using Shigao saves it, turning death to life instantly. Those who kill with Shigao misuse it for non-Stomach Fire. The fiercest fires in the body are Stomach Fire and Kidney Fire. Stomach Fire should be purged; Kidney Fire should be tonified. Using Shigao to purge Kidney Fire instead of Stomach Fire inevitably kills. The difference in tonification/purging between Kidney and Stomach Fire lies in mistakenly applying purging to what should be tonified, misled by theories that Huangbai and Zhimu descend Kidney Fire. Cold/cool drugs do not inherently kill; those killed by misuse bear no blame on Shigao.
Someone again doubts: Discarding the combined use of Huangbai and Zhimu implies Zhimu should not aid cold/cool drugs to kill. Why do you praise Zhimu aiding Shigao to save lives? I replied: Excessive Stomach Fire should ideally be treated by directly descending Stomach Fire using Shigao, without Zhimu. However, Stomach Fire becomes excessive due to Kidney Water deficiency, unable to control fire. Excessive Stomach Fire scorches Kidney Water; if water is exhausted, fire blazes to the sky, and death is immediate. Using Shigao to purge Stomach Fire is urgently saving Kidney Water. But merely saving Kidney Water while Kidney Fire increases heat means Stomach Fire remains strong and does not extinguish quickly. Thus, Zhimu is used to temporarily retreat Kidney Fire, so Stomach Fire loses allies and is easier to extinguish. This assistance of Zhimu with Shigao is a temporary expedient, not a permanent plan.
Someone asks: Shigao purges Stomach Fire; once purged, why use Zhimu? Praising Zhimu's merit seems biased. I replied: Shigao purges Stomach Fire to save Kidney Water, but cannot purge Kidney Fire via Stomach Fire. The Stomach is the gate of the Kidney. If Stomach Fire ceases but Kidney Fire remains, the gate is quiet but internal fire burns, which is not peaceful. Thus, purging Stomach Fire implies purging Kidney Fire. Purging Kidney Fire requires Zhimu. Moreover, Zhimu not only purges Kidney Fire but also Stomach Fire. Used with Shigao, they work in concert; protecting the Kidney protects the Stomach, unlike Huangbai which only purges Kidney Fire without affecting the Stomach.
Someone asks: Baihu Tang is thoroughly explained, but Shigao's use in Da Qinglong Tang and Xiao Qinglong Tang is not discussed. Can White Tiger kill but Green Dragon not? I replied: Green Dragon nature is hard to tame; improper use kills just like White Tiger. The same Shigao is called Dragon or Tiger based on usage. Used in heat-dispersing contexts, it is named Green Dragon; used in cold-dispersing contexts, White Tiger. Shigao is very cool; used internally with heat, it resolves heat without fearing coolness; used internally with cold, it is overly cool, causing changes despite reducing heat. Baihu Tang seems fiercer than Qinglong Tang. However, pathogen in Stomach requires Baihu Tang to resolve heat; pathogen not yet in Stomach but entering requires Qinglong Tang. Shigao combined with Guizhi (Cinnamon Twig) and Mahuang (Ephedra) tends to ascend. In Qinglong Tang, Shigao must be used in small amounts, unlike Baihu Tang where heavy doses are allowed.
Someone asks: Do Da and Xiao Qinglong Tang names depend on Shigao dosage? I replied: Shigao should not be used in large amounts, not just in Xiao Qinglong Tang. The difference between Xiao and Da Qinglong Tang is the use of Shaoyao (Paeonia Root). Although Dragon nature is hard to tame, Shaoyao's sour astringency prevents Shigao from ascending; Shaoyao controls Shigao. Like a young dragon growing horns, afraid to hurt others, cautious, hence named Small. People know Shigao's ferocity, but who knows that adding Shaoyao makes Shigao harmless? Improper use of Shigao in Xiao Qinglong Tang still has dangers, but less chaotic than unconstrained Da Qinglong Tang.
Asked again: Since Da Qinglong is too chaotic, why not add Shaoyao? I replied: This is also inadvisable. Pathogen between Ying and Wei, moving toward Yangming, requires urgent Da Qinglong Tang to bring rain and dissipate heat. Adding Shaoyao's sour astringency prevents wind and clouds from meeting, resulting in excessive convergence and insufficient abundance. Master Zhongjing specifically formulated Da Qinglong Tang to pour rain, not merely rely on cool breezes.