脉涩、面白带忧、喘嗽、下衄者，兼肺有燥也；脉微、面黑、善恐、耳闭、气逆而泄，兼肾有寒也。凡邪出于
外则为腑、为表，入于内则为脏、为里。不拘何脏何腑，表证必同归于太阳，里证必同归于阳明。噫！法无定
用，病有定体，知此则百病机关，一悟可了，又何疑于手经之不受病耶！
上一段论六经正病。
表可汗而里可下，
表证属太阳。凡见头疼、发热、恶寒、清便自调、腰项脊强、脉浮紧者，即是表证，不拘日数多少，便宜解
表，不宜下渗。有汗为表虚，宜解肌；无汗为表实，宜发汗。但发汗亦有轻重不同，古谓春夏宜汗者，借天时
而喻阳邪在外也。其实春月阳气尚微，秋月阳气欲敛，俱不可大汗。夏月天气热，玄府开，不必大汗。冬月阳
气伏藏，感冒轻者，尤不宜汗。惟伤寒重者，时令严栗，皮毛坚致，非大汗无由得散，不得已而从权也。至于阴
证，但厥无汗者，妄汗动经则死，或有表邪，辛热微汗以散之可也。里证始焉脉浮而大，今则沉而数；始焉惺
而静，今则躁而动；始焉头疼发热恶寒，今则不恶寒反恶热，烦躁倍加，胸连脐腹满痛，腋下掌心自汗 ，
以致胃干粪燥，大便不通，小便赤涩，口渴，发狂，谵语，掀衣揭被，扬手掷足，六脉有力，即是传经热证。
又谓阳盛误汗即死。或有初病即见此证者，不拘日数多少，便宜通利，失下则血气不通而发厥矣。抑又有说焉，
纯乎表而里无一毫病者，当解表时勿攻里；纯乎里而表无一毫病者，当攻里时勿解表；如表里俱见，或表多里
少，表急里缓，则先治其表而后攻其里；或里多表少，里急表缓，则先攻其里而后救其表也。又表虚里实，则
药宜辛凉；里虚表实，则药宜辛热，皆以里为主，内气正而后可以治表。虽莫急于内，表亦不可缓也，表里虚
实，而医之大分明矣。
表里半者，宣吐与和；
凡病，或渴或不渴，或胸中烦不烦，或呕不呕，或腹胁痛不痛，或咳，或心下悸，或小便不利，或有为
之证，少阳所主也。邪在表则多寒；邪在里则多热；邪在半表里，则寒热往来。邪在表，则心腹不满；邪在里，
则心腹胀满；邪在半表里，则胸胁满。邪在表，则呻吟不安；邪在里，则狂言乱语；邪在半表里，则欲言不言。
邪在表，则小便清而易；邪在里，则小便浊而难；邪在半表里，或利或不利。邪在表，则不烦不渴不呕；邪在里，
则烦满而渴。故或烦或呕者，邪在表方传里也。若见耳聋、胁痛、寒热、呕而口苦、胸胁紧满，脉见弦数者，即
是半表半里。脉大，胸满多痰者，或挟宿食，可吐。《百问》云∶气浮上部，填塞心胸，头痛多涎，此吐证也。
《内经》云∶其高者，因而越之。脉虽大无顽痰者，不可吐，只当和解。古谓春宜吐者，顺阳气发生于上也；
秋冬宜下者，顺阳气收敛于内也。此亦道其常耳，有病皆当从权。
阳可寒而阴可热，
概言之，三阳经病即阳证，手之三阳从头走足，故头疼身热云云；三阴经病即阴证，足之三阴从足走腹，
故腹痛自利云云。然阴阳俱
有表里二证，阳证表里同归于热而已，阴证表郁似阳，入里则有传经、直中之殊。大抵阳证之表，发热恶寒，
清便自调，面光声亮，鼻息往来如常，手足温。阳证之里，唇焦舌燥，爪甲红活，身轻易于转侧，烦渴，掀衣，
扬手掷足，大便或闭或硬，小便或赤或涩，脉浮洪数，宜汗、吐、下、和四法以治之。阴证之表，无热恶寒，
面惨声短，鼻息往来气冷，手足厥逆。阴证之里，唇紫舌卷，爪甲青黑，身重难于转侧，不渴，引衣，卧多蜷
足，大便泄利，小便清白，脉细沉微，每与阳证相反。盖阳证自下而上，故初起有头疼，阴证则无头疼也。
阳证自外传入，故郁而为热，阴证则无身热而反厥冷也。阳证摇手掷足，阴证则卧多蜷足。阳证内热而渴，阴
证则不渴。阳证二便闭，阴证二便清且利也。惟有腹痛与呕，阴阳二证俱有，然阴脉沉微。凡言阳证，多得之
风寒暑湿，邪生于太阳也；凡言阴证，多得之饮食起居喜怒，邪生于少阴也。故云伤寒挟内伤者，十居八九，
此阴阳正病也。
阴阳极者，从治非讹。
阳邪不深，不能至于厥逆；阴邪不甚，不能至于烦躁。此水极似火，火极似水，谓之反化，亢极则害之义
也。阳证潮汗秘赤，满渴狂谵，甚则斑血喘急，然热极忽然伏于内，故身寒四肢厥逆，状若阴证。但身虽冷
而不欲近衣，神虽昏而气色光润，脉必沉滑而有力，此阳极似阴也，宜大柴胡汤下之，或白虎汤、竹叶石膏汤。
阴证厥冷吐利，不渴静蜷，甚则咽痛郑声，然寒极忽然火浮于外，发躁扰乱，状若阳证。然身虽烦躁而引衣目
盖，口虽燥渴而饮水不下，脉必沉细无力，此阴极似阳也，宜通脉四逆汤。从治者，反攻也，热药冷冻饮料，冷药
热饮，或热药为君而佐以凉药，或冷药为君而佐以热剂，亦非判然如庸医之差讹也。借有热病服热药而愈者，
必先服寒药过多；寒病服寒药而愈者，必先服热药过多故耳。若夫以寒治热，以热治寒，此为逆治。逆治者，
正治也。正治之法，人孰不知之乎！
表里俱无，不可犯上犯下；
伤寒，头痛寒热，表也。口失滋味，腹中不和，或闭或泄，里也。若四五日后，以至过经十三日，既无表
证，又无里证，身微热者，虚热耳，小柴胡汤和之。不可汗、吐以犯上焦清气，不可大下以犯下焦胃气。身热，
目中不了了，睛不和，大便硬者，乃可大柴胡，小承气下之。设或已下而脉数，消谷善饥，六七日不大便者，
瘀血症也。
表里俱有，察其孰少孰多。
表里俱见，必分多少治之。脉浮而大为表，烦渴尿赤为里，五苓散主之。头疼身热便闭为里，小便清利
为表，桂枝汤主之。心满不食便闭为里，恶寒头汗为表，小柴胡汤主之。太阳病因下早而协热下利，心痞硬者，
谓之表里不解，桂枝人参汤。太阳病因下早而腹痛有积者，谓之太阳太阴，又谓之里传表，挂枝加芍药汤，甚者
加大黄。太阳病下早利不止，脉促，喘而汗出，表未解也，葛根芩连汤。脉弦胸满者，栀豉汤吐之。通治表多
里少者，白虎汤或合小柴胡汤。里多表少者，五苓散或合小柴胡汤。表里俱急者，防风通圣散、大柴胡汤。
当汗而下，则为瘀血懊 痞气结胸之患；
太阳证，脉浮紧者，宜汗。而汗之不解者，再与汗之。若失其汗，则寒邪传经，当看传过何经，变出何
病。若应汗而反下渗，表邪乘虚内陷，则热蓄于里，变为瘀血、懊 、痞气，结胸等证。
当下而汗，则为悸惕亡阳谵语厥竭之 。
里证具而脉沉实者，宜下。若下后热不退，脉未和者，犹当量虚实再下。若失下则邪无从出，又或应下
而反汗之，则津液内竭，变为动悸等证。
不可汗，诸虚咽疮淋血坏证，动气与风温风湿脉迟；
可汗者，脉证全在表也，然太早太过，则津液竭而变生焉。有不可汗者，诸虚损咽干口燥，咽痛疮疡，
淋沥，经水适至，诸失血，吐沫咳嗽坏证，脐中上下左右动气，风温、风湿、湿温、脉迟微涩者，或厥而脉紧
者，俱宜和解，不宜汗。若强发之，病微者难瘥，剧者言乱目眩而死。
不可下，诸虚咽肿呕厥结胸，动气与脉浮脉虚带表。
可下者，脉证全在里也，然太早太过，则水谷脱而变生焉。有不可下者，诸虚，咽肿，呕吐厥逆，结胸
不转矢气，脐中左右上下动气，脉浮细虚微涩，带表恶寒等证。下之则危，随宜以温热药救之。
阴虚挟火而脉数，（不可）灸之者消；
阴阳二毒，及少阴证吐利，及口和背恶寒脉微涩，属阳虚者，宜灸。阴虚挟火脉微数者，不宜灸。盖外
火能助内火，火炎则下体必重痹，骨焦肉消，或因此遗精潮咳见红，皆火气之所使也。《活人》云∶凡灸后，
烧针后，证与火邪发狂者同，小柴胡加龙骨牡蛎治之。
膈寒肢冷而脉微，（不可）吐之者夭。
膈上寒饮干呕，少阴病也；四肢冷，胃亏也；脉微，下虚也。误吐内烦，损伤元气，遂致不救者有之。若
应吐而反温之，则毒瓦斯郁结于胃，而为发狂等证。
急下以救水，存液之机甚微；
伤寒，热气入脏，流于少阴之经，咽路焦，口燥渴，肾水干也；热病，热不已，目睛不和，亦肾水干也，
皆急下以救肾水。阳明发热汗多，或已汗不解，腹满痛，及狂谵不大便者，皆急下以存胃液。伤寒脉弦而迟，
弦为寒，迟为脏；脉大而紧，大为阳，紧为寒，俱谓之阳中伏阴，急下以分阴阳。又下利三部脉平，心下硬者，
内实也；下利脉迟而滑，或浮大按之反涩，恶食者，皆胃有宿食也。但宿食忌巴霜，只宜大黄荡涤。
急温以和阳，止呕之功非小。
脉沉厥冷，膈上寒饮干呕，或时头痛，皆寒气上攻也，急温之，三味参萸汤。内寒已极，厥逆吐利，不
渴静蜷，阳和之气欲绝，六脉若有若无，急温之，四逆汤。凡言急者，病势已笃，将有变革，非若他病可以缓也。
他如太阳汗出不止，汗后恶风，汗后烦躁，心悸身痛，皆宜急用附子加于桂枝，芍药之类三阳脉迟腹痛，建中
汤当先施也。但一服，中病即止，伤寒之药皆然。
过经（不解）汗下从轻，
伤寒六日，传经一遍，七日当解，再传至于十三日以上不愈，谓之过经。汗下失宜，以致邪气留连不已，
神昏谵语，胸满潮渴，随其表里证见而调之，或从轻再汗再下。如脉乱发躁，尺寸陷者危。如脉缓安睡，邪未
净者，正未复耳，参胡芍药汤调之。有大便下利而脉和者，知医以丸药下与，停留余热。凡过经气虚，或加异
气，宜与坏证参看。
尺迟暂补何忌。
凡尺寸迟弱，血少也。不问风寒初证杂证，俱忌汗吐下，宜先以小建中汤，或黄 建中汤救脉。如素实
者，小柴胡汤亦好，俟脉不迟，方可施治。
发表攻里温里之方，扶阳助阴抑阴之义。
此阴阳，指表里言。病者为虚，不病者为实。表病里和，则邪出于外而为阳虚阴盛，故发表不远热，而用
辛甘之剂，所以扶阳也。里病表和，则邪入于内而为阴虚阳盛，故攻里不远寒，而用酸苦之药，所以扶阴也。
若阴经自受寒邪，则为脏病投阴，阳气将脱，急宜辛热回阳抑阴。故曰∶桂枝下咽，阳盛则毙；承气入胃，阴盛
乃亡。实实虚虚，损不足而益有余，医杀之耳。此汗、下之杼机。
法以得中为贵，不及愈于太过；
法，谓汗、吐、下、温、解五法，各有不同。汗有大汗发表，微汗解肌，以别轻重。下有急下、少与、微
和、渗利，以厘清浊。温有兼补者。
吐有宣涌、探引，或只宽利而不敢吐者。和解则一而已。或曰伤寒无补法，热气得补复盛，更复下之，是重困
也，惟虚烦里寒阴证，不在此例。得中者，五法洞中恳剧；太过者，粗工猛进；不及者，中工从缓从轻。凡伤
寒汗下药，一服中病即止，不必尽剂，与杂病不同。伤寒不过汗吐下三证，若用之得当，有何传变，全在医者
精明审处之耳。
证有似是而非，不识宁可不治。
伤寒题目未定之时，不知有无风湿、劳役、痰食等项相兼，似是而非，最宜详辨，故不知者，宁可不治。
班固有言曰∶有病不治得中医。倘一药之误，悔将噬脐。噫！古以医药救夭札，今以医药治其生，治生可也，
而误人于死，岂不与谋劫者同哉！慎之！慎之！
上一段论表里阴阳汗吐下温解法。
脉象涩、面色白且带有忧色、气喘咳嗽、鼻衄的，是兼有肺燥；脉象微、面色黑、易惊恐、耳闭、气逆而泄泻的，是兼有肾寒。凡是邪气出于外则为腑、为表，进入内则为脏、为里。不论涉及何脏何腑，表证必然归属于太阳经，里证必然归属于阳明经。唉！治疗方法没有固定的模式，但疾病有其确定的本质，明白了这一点，就能领悟百病的机关，一悟即通，又何必怀疑手经不受病呢！
上一段论述六经的正病。
表证可用发汗法，里证可用攻下法，
表证属于太阳经。凡是见到头痛、发热、恶寒、大小便正常、腰项脊背强痛、脉象浮紧的，就是表证，不论患病天数多少，都应当及时解表，不宜使用攻下渗利之法。有汗的为表虚证，宜用解肌法；无汗的为表实证，宜用发汗法。但是发汗也有轻重不同，古人说春夏适宜发汗，是借天时来比喻阳邪在体表。其实春季阳气尚微弱，秋季阳气欲收敛，都不可以大汗。夏季天气热，玄府（汗孔）开放，不必大汗。冬季阳气伏藏，感冒轻者，尤其不宜发汗。只有伤寒重症，时令严寒，皮毛坚致，非大汗不能使邪气散出，这是不得已而采取的权宜之计。至于阴证，只有四肢厥冷而无汗的，如果妄用发汗触动经脉就会死亡；如果有表邪，可用辛温热药微汗以发散之。里证起初脉象浮大，现在变为沉数；起初神志清醒安静，现在躁动不安；起初头痛发热恶寒，现在不恶寒反而恶热，烦躁加倍加重，胸部连及脐腹部胀满疼痛，腋下掌心自汗，导致胃干粪燥，大便不通，小便赤涩，口渴，发狂，说胡话，掀开衣服被子，扬手掷足，六脉有力，这就是传经的热证。又说阳盛误用发汗就会死亡。或者有初病就见此证的，不论天数多少，都应当及时通利，错过攻下的时机则血气不通而发生厥逆。又有说法说，纯然是表证而里无一毫病痛的，当解表时不要攻里；纯然是里证而表无一毫病痛的，当攻里时不要解表；如果表里症状都出现，或者表多里少，表急里缓，就先治其表而后攻其里；或者里多表少，里急表缓，就先攻其里而后救其表。还有表虚里实，药物宜用辛凉；里虚表实，药物宜用辛热，都以里证为主，内气正气恢复后才能治疗表证。虽然调理内部最为紧急，但解表也不可迟缓，表里的虚实，医理就非常明确了。
表里各半者，用宣吐与和解法；
凡是生病，或渴或不渴，或胸中烦或不烦，或呕或不呕，或腹胁痛或不痛，或咳嗽，或心下悸动，或小便不利，或有其他各种症状，都是少阳经所主。邪气在表则多寒；邪气在里则多热；邪气在半表半里，则寒热往来。邪气在表，则心腹不满；邪气在里，则心腹胀满；邪气在半表半里，则胸胁满闷。邪气在表，则呻吟不安；邪气在里，则狂言乱语；邪气在半表半里，则想说话却说不出来。邪气在表，则小便清亮而易解；邪气在里，则小便浑浊而难解；邪气在半表半里，或腹泻或不便。邪气在表，则不烦不渴不呕；邪气在里，则烦满而渴。所以如果出现烦或呕的症状，说明邪气正在从表传入里。如果见到耳聋、胁痛、寒热往来、呕吐且口苦、胸胁紧满，脉象弦数的，就是半表半里证。脉象大，胸满多痰的，或者挟带宿食，可以用吐法。《百问》说：气浮于上部，填塞心胸，头痛多涎，这是吐证。《内经》说：病位高的，因而使其涌越而出。脉象虽大但没有顽痰的，不可用吐法，只应当和解。古人说春季适宜吐，是顺应阳气发生于上；秋冬适宜下，是顺应阳气收敛于内。这也是说常法罢了，有病都应当权变处理。
阳证可用寒凉药，阴证可用温热药，
概括来说，三阳经的病就是阳证，手三阳经从头走足，所以有头疼身热等症；三阴经的病就是阴证，足三阴经从足走腹，所以有腹痛自利等症。然而阴阳都有表里二证，阳证的表里都归于热而已，阴证的表证郁滞似阳，入里则有传经和直中的区别。大致阳证的表证，发热恶寒，大小便正常，面色光亮声音洪亮，鼻息往来如常，手足温暖。阳证的里证，嘴唇焦裂舌苔干燥，指甲红润，身体轻便易于转侧，烦躁口渴，掀衣，扬手掷足，大便或闭结或硬结，小便或赤或涩，脉象浮洪数，宜用汗、吐、下、和四法治疗。阴证的表证，无热恶寒，面色惨淡声音短促，鼻息往来气冷，手足厥逆。阴证的里证，嘴唇紫暗舌体卷缩，指甲青黑，身体沉重难于转侧，不渴，拉衣覆盖，卧姿多蜷曲双脚，大便泄利，小便清白，脉象细沉微，往往与阳证相反。大概阳证自下而上发展，所以初起有头疼，阴证则没有头疼。阳证自外传入，所以郁滞而为热，阴证则没有身热反而厥冷。阳证摇手掷足，阴证则卧姿多蜷曲双脚。阳证内热而渴，阴证则不渴。阳证二便闭结，阴证二便清且利。只有腹痛与呕吐，阴阳二证都有，但阴证脉象沉微。凡是说阳证，多因风寒暑湿所致，邪气生于太阳经；凡是说阴证，多因饮食起居喜怒所致，邪气生于少阴经。所以说伤寒挟带内伤的，十居八九，这是阴阳正病。
阴阳极甚者，采用从治法并非错误。
阳邪不深，不能导致厥逆；阴邪不重，不能导致烦躁。这是水极似火，火极似水，称为反化，是亢极则害的道理。阳证出现潮汗、便秘、尿赤、满闷、口渴、发狂、谵语，甚至斑疹出血、气喘急促，然而热极忽然伏于内，所以身体寒冷四肢厥逆，状若阴证。但身体虽冷却不欲近衣被，神志虽昏但气色光润，脉象必沉滑而有力，这是阳极似阴，宜用大柴胡汤攻下，或用白虎汤、竹叶石膏汤。阴证出现厥冷、呕吐、泄利，不渴、安静、蜷卧，甚至咽痛、郑声（语言重复低微），然而寒极忽然火浮于外，发生烦躁扰乱，状若阳证。但身体虽烦躁却拉衣遮盖双目，口虽燥渴却饮水不下，脉象必沉细无力，这是阴极似阳，宜用通脉四逆汤。从治法，就是反攻法，热药冷服，冷药热服，或者热药为主而佐以凉药，或者冷药为主而佐以热剂，也不是像庸医那样截然错误的区分。假如有热病服热药而愈的，一定是先前服寒药过多；寒病服寒药而愈的，一定是先前服热药过多罢了。如果用寒治热，用热治寒，这叫逆治。逆治，就是正治。正治的方法，谁不知道呢！
表里俱无，不可犯上犯下；
伤寒，头痛寒热，是表证。口失滋味，腹中不和，或闭或泄，是里证。如果四五日后，以至过经十三日，既无表证，又无里证，身体微热的，是虚热，用小柴胡汤和解。不可用汗、吐法侵犯上焦清气，不可用大下法侵犯下焦胃气。如果身体热，眼睛看不清，眼球转动不灵活，大便硬的，才可用大柴胡汤、小承气汤攻下。假如已经攻下而脉数，消谷善饥，六七日不大便的，是瘀血症。
表里俱有，要察看孰少孰多。
表里症状都出现，必须分清楚多少再治。脉浮大为表，烦渴尿赤为里，用五苓散主治。头疼身热便闭为里，小便清利为表，用桂枝汤主治。心满不食便闭为里，恶寒头汗为表，用小柴胡汤主治。太阳病因过早攻下而协热下利，心下痞硬的，叫做表里不解，用桂枝人参汤。太阳病因过早攻下而腹痛有积滞的，叫做太阳太阴，又叫里传表，用桂枝加芍药汤，严重的加大黄。太阳病过早攻下导致利不止，脉促，喘而汗出，表未解的，用葛根芩连汤。脉弦胸满的，用栀豉汤吐之。通治表多里少的，用白虎汤或合用小柴胡汤。里多表少的，用五苓散或合用小柴胡汤。表里俱急的，用防风通圣散、大柴胡汤。
应当发汗而误用攻下，则会导致瘀血、懊憹、痞气、结胸的祸患；
太阳证，脉浮紧的，宜发汗。而发汗后不解的，再给予发汗。如果错失发汗时机，则寒邪传经，应当看传过哪一经，变出什么病。如果应当发汗反而误用攻下渗利，表邪乘虚内陷，则热蓄于里，变为瘀血、懊憹、痞气、结胸等证。
应当攻下而误用发汗，则会导致惊悸、惕惧、亡阳、谵语、厥竭的祸患。
里证具备而脉沉实的，宜攻下。如果攻下后热不退，脉未调和的，还应当衡量虚实再次攻下。如果错失攻下时机则邪气无从出路，或者应当攻下反而误用发汗，则津液内竭，变为动悸等证。
不可发汗的情况：诸虚损、咽疮、淋证、血证、坏证、动气与风温风湿脉迟；
可发汗的，脉证全在表也，然而太早太过，则津液枯竭而变生他病。有不可发汗的，诸虚损咽干口燥，咽痛疮疡，淋沥，月经适至，各种失血，吐沫咳嗽坏证，脐中上下左右动气，风温、风湿、湿温、脉迟微涩的，或者厥而脉紧的，都宜和解，不宜发汗。如果强行发汗，病轻者难愈，病重者言语错乱目眩而死。
不可攻下的情况：诸虚损、咽肿、呕吐、厥逆、结胸、动气与脉浮脉虚带表。
可攻下的，脉证全在里也，然而太早太过，则水谷脱失而变生他病。有不可攻下的，诸虚损，咽肿，呕吐厥逆，结胸不转矢气，脐中左右上下动气，脉浮细虚微涩，带表恶寒等证。攻下则危险，随宜用温热药救治。
阴虚挟火而脉数，（不可）灸之者会消耗阴液；
阴阳二毒，以及少阴证吐利，以及口中和背恶寒脉微涩，属阳虚的，宜灸。阴虚挟火脉微数的，不宜灸。因为外火能助内火，火炎则下体必重痹，骨焦肉消，或者因此遗精、潮咳、见红，都是火气的作用。《活人书》说：凡灸后，烧针后，证候与火邪发狂相同的，用小柴胡加龙骨牡蛎汤治疗。
膈寒肢冷而脉微，（不可）吐之者会致死。
膈上寒饮干呕，是少阴病；四肢冷，是胃亏；脉微，是下虚。误用吐法导致内烦，损伤元气，遂致不治的有这种情况。如果应当吐而反用温法，则毒瓦斯郁结于胃，而为发狂等证。
急下以救肾水，存留阴液的时机非常微妙；
伤寒，热气入脏，流于少阴之经，咽路焦，口燥渴，是肾水干涸；热病，热不已，目睛不和，也是肾水干涸，都应当急下以救肾水。阳明发热汗多，或者已汗不解，腹满痛，以及狂谵不大便的，都应当急下以存胃液。伤寒脉弦而迟，弦为寒，迟为脏；脉大而紧，大为阳，紧为寒，都叫作阳中伏阴，急下以分阴阳。又下利三部脉平，心下硬的，是内实；下利脉迟而滑，或浮大按之反涩，恶食的，都是胃有宿食。但宿食忌用巴豆霜，只宜用大黄荡涤。
急温以调和阳气，止呕的功效不小。
脉沉厥冷，膈上寒饮干呕，或时头痛，都是寒气上攻，急温之，用三味参萸汤。内寒已极，厥逆吐利，不渴静蜷，阳和之气欲绝，六脉若有若无，急温之，用四逆汤。凡是说急的，病势已重，将有变革，不像其他病可以缓慢处理。其他如太阳汗出不止，汗后恶风，汗后烦躁，心悸身痛，都宜急用附子加于桂枝、芍药之类。三阳脉迟腹痛，建中汤应当先施用。但一服，中病即止，伤寒的药物都是这样。
过经（不解）汗下从轻，
伤寒六日，传经一遍，七日当解，再传至于十三日以上不愈，叫做过经。汗下失宜，以致邪气留连不已，神昏谵语，胸满潮渴，随其表里证见而调之，或从轻再汗再下。如脉乱发躁，尺寸脉陷下的危重。如脉缓安睡，邪未净的，是正气未复，用参胡芍药汤调之。有大便下利而脉和的，知道医生用丸药攻下，停留余热。凡是过经气虚，或夹杂异气，宜与坏证参看。
尺脉迟暂且补益有何忌讳。
凡是尺寸脉迟弱，是血少。不问风寒初证杂证，都忌汗吐下，宜先用小建中汤，或黄芪建中汤救脉。如素体实者，小柴胡汤也好，等到脉不迟，方可施治。
发表攻里温里之方，扶阳助阴抑阴之义。
这里的阴阳，指表里而言。病者为虚，不病者为实。表病里和，则邪出于外而为阳虚阴盛，所以发表不远热，而用辛甘之剂，所以扶阳。里病表和，则邪入于内而为阴虚阳盛，所以攻里不远寒，而用酸苦之药，所以扶阴。若阴经自受寒邪，则为脏病投阴，阳气将脱，急宜辛热回阳抑阴。所以说：桂枝下咽，阳盛则毙；承气入胃，阴盛乃亡。实实虚虚，损不足而益有余，是医生杀人罢了。这是汗、下的关键。
法以得中为贵，不及优于太过；
法，谓汗、吐、下、温、解五法，各有不同。汗有大汗发表，微汗解肌，以别轻重。下有急下、少与、微和、渗利，以厘清浊。温有兼补的。
吐有宣涌、探引，或只宽利而不敢吐的。和解则只有一种。有人说伤寒无补法，热气得补复盛，更复下之，是重困也，惟虚烦里寒阴证，不在此例。得中的，五法洞中肯綮；太过的，粗工猛进；不及的，中工从缓从轻。凡是伤寒汗下药，一服中病即止，不必尽剂，与杂病不同。伤寒不过汗吐下三证，若用之得当，有何传变，全在医者精明审处之耳。
证有似是而非，不认识宁可不予治疗。
伤寒题目未定之时，不知有无风湿、劳役、痰食等项相兼，似是而非，最宜详辨，故不知者，宁可不治。班固有言曰：有病不治得中医。倘一药之误，悔将噬脐。唉！古以医药救夭札，今以医药治其生，治生可也，而误人于死，岂不与谋劫者同哉！慎之！慎之！
上一段论述表里阴阳汗吐下温解法。
Pulse is choppy, complexion is white with an expression of sorrow, accompanied by panting and coughing, and epistaxis: this indicates a concurrent dryness in the Lung. Pulse is faint, complexion is black, prone to fear, ear congestion, rebellious Qi leading to diarrhea: this indicates a concurrent cold in the Kidney. Generally, when pathogenic factors emerge outward, they affect the Fu organs and the Exterior; when they enter inward, they affect the Zang organs and the Interior. Regardless of which Zang or Fu organ is involved, Exterior syndromes invariably belong to the Taiyang (Greater Yang) channel, and Interior syndromes invariably belong to the Yangming (Bright Yang) channel. Alas! Treatment methods are not fixed, but diseases have definite characteristics. Understanding this allows one to comprehend the mechanisms of all diseases with a single insight, and why should one doubt that the Hand channels do not receive disease?
The preceding paragraph discusses the primary diseases of the Six Channels.
Exterior syndromes can be treated with sweating, and Interior syndromes with purgation.
Exterior syndromes belong to the Taiyang channel. Whenever headache, fever, aversion to cold, normal bowel and bladder functions, stiffness of the waist, neck, and spine, and a floating-tight pulse are present, it is an Exterior syndrome. Regardless of the number of days since onset, exterior-releasing measures should be taken promptly, and purgative or draining methods should be avoided. Sweating indicates an Exterior deficiency syndrome, suitable for muscle-relieving methods; no sweating indicates an Exterior excess syndrome, suitable for sweating methods. However, sweating methods vary in intensity. The ancients stated that sweating is appropriate in spring and summer, using the seasonal climate as an analogy for yang pathogens being on the exterior. In reality, in spring, yang Qi is still weak; in autumn, yang Qi is about to converge; thus, heavy sweating should be avoided in both seasons. In summer, the weather is hot, and the xuankou (sweat pores) are open, so heavy sweating is unnecessary. In winter, yang Qi is hidden and stored; for mild colds, sweating is particularly inappropriate. Only in severe cases of Shanghan (Cold Damage), when the season is bitterly cold and the skin and hair follicles are tight, can heavy sweating disperse the pathogen; this is a necessary expedient. For Yin syndromes, if there is only cold extremities without sweating, reckless sweating will disturb the meridians and cause death. If there is an exterior pathogen, mild sweating with pungent-warm herbs can disperse it. Interior syndromes initially present with a floating and large pulse, now becoming deep and rapid; initially clear-minded and quiet, now restless and agitated; initially headache, fever, and aversion to cold, now no longer averse to cold but rather averse to heat, with doubled restlessness and irritability, distension and pain extending from the chest to the umbilicus and abdomen, spontaneous sweating in the axillae and palms, leading to dry stomach and hardened stool, constipation, dark and scanty urination, thirst, mania, delirium, throwing off clothes and blankets, flinging hands and legs, and strong pulses in all six positions: this is a transmitted heat syndrome. It is also said that misusing sweating in Yang excess leads to death. If these symptoms appear at the onset of illness, regardless of the duration, prompt purgation is required; failing to purge will lead to obstruction of Qi and blood and result in cold extremities. Furthermore, if the syndrome is purely Exterior with no trace of Interior involvement, do not attack the Interior when treating the Exterior; if it is purely Interior with no trace of Exterior involvement, do not release the Exterior when attacking the Interior. If both Exterior and Interior signs are present, or if Exterior is predominant and Interior is minor, or if Exterior is urgent and Interior is slow, treat the Exterior first and then the Interior. If Interior is predominant and Exterior is minor, or if Interior is urgent and Exterior is slow, attack the Interior first and then rescue the Exterior. Additionally, for Exterior deficiency and Interior excess, use pungent-cool herbs; for Interior deficiency and Exterior excess, use pungent-warm herbs. In both cases, focus on the Interior; once the internal Qi is rectified, the Exterior can be treated. Although addressing the Interior is most urgent, releasing the Exterior cannot be delayed. The distinction between Exterior/Interior and Deficiency/Excess makes medical principles clear.
When Exterior and Interior are equally involved, use emesis and harmonizing methods.
In any illness, whether thirsty or not, whether vexed in the chest or not, whether vomiting or not, whether abdominal or hypochondriac pain exists or not, whether coughing occurs, whether palpitations in the epigastrium are present, or whether urination is difficult, or other various symptoms arise, these are governed by the Shaoyang (Lesser Yang) channel. Pathogens in the Exterior tend to cause cold; pathogens in the Interior tend to cause heat; pathogens in the Half-Exterior/Half-Interior cause alternating chills and fever. Pathogens in the Exterior do not cause fullness in the heart and abdomen; pathogens in the Interior cause fullness in the heart and abdomen; pathogens in the Half-Exterior/Half-Interior cause fullness in the chest and hypochondrium. Pathogens in the Exterior cause groaning and restlessness; pathogens in the Interior cause wild talk and confusion; pathogens in the Half-Exterior/Half-Interior cause a desire to speak but inability to do so. Pathogens in the Exterior result in clear and easy urination; pathogens in the Interior result in turbid and difficult urination; pathogens in the Half-Exterior/Half-Interior may cause diarrhea or normal urination. Pathogens in the Exterior cause no vexation, thirst, or vomiting; pathogens in the Interior cause vexation, fullness, and thirst. Therefore, if vexation or vomiting appears, it indicates the pathogen is transmitting from the Exterior to the Interior. If deafness, hypochondriac pain, alternating chills and fever, vomiting with bitter taste, tight fullness in the chest and hypochondrium, and a string-taut and rapid pulse are observed, it is a Half-Exterior/Half-Interior syndrome. A large pulse with chest fullness and much phlegm, or retention of undigested food, may be treated with emesis. *Baiwen* states: Qi floating in the upper part, blocking the chest and heart, headache with excessive saliva—this is an indication for emesis. *Neijing* states: "Where the pathology is high, induce vomiting to expel it." If the pulse is large but there is no stubborn phlegm, emesis is contraindicated; harmonizing is appropriate. The ancients said spring is suitable for emesis to follow the rising of Yang Qi; autumn and winter are suitable for purgation to follow the converging of Yang Qi inward. This describes the general rule, but treatment must adapt to specific conditions.
Yang syndromes can be treated with cold, and Yin syndromes with warm.
Generally, diseases of the Three Yang channels are Yang syndromes; the Hand Three Yang channels run from head to foot, hence symptoms like headache and body heat. Diseases of the Three Yin channels are Yin syndromes; the Foot Three Yin channels run from foot to abdomen, hence symptoms like abdominal pain and spontaneous diarrhea. However, both Yin and Yang have Exterior and Interior syndromes. Yang syndromes' Exterior and Interior both manifest as heat. Yin syndromes' Exterior stagnation may resemble Yang, but upon entering the Interior, there is a distinction between transmitted disease and direct transmission. Generally, Yang Exterior syndromes present with fever and aversion to cold, normal bowel/bladder function, bright complexion and loud voice, normal nasal respiration, and warm hands and feet. Yang Interior syndromes present with cracked lips and dry tongue, ruddy nails, ease of movement, restlessness and thirst, throwing off clothes, flinging limbs, constipation or hard stools, dark or scanty urine, and a floating, surging, rapid pulse; treat with sweating, emesis, purgation, and harmonizing methods. Yin Exterior syndromes present with no fever but aversion to cold, pale complexion and short voice, cold nasal respiration, and cold extremities. Yin Interior syndromes present with purple lips and curled tongue, cyanotic/black nails, heaviness of body and difficulty moving, no thirst, pulling clothes over oneself, sleeping curled up, diarrhea, clear and profuse urine, and a fine, deep, faint pulse; these are often opposite to Yang syndromes. Yang syndromes develop from bottom to top, so headache appears early; Yin syndromes do not have headache. Yang syndromes transmit from outside, causing stagnation and heat; Yin syndromes have no body heat but instead cold extremities. Yang syndromes involve flinging limbs; Yin syndromes involve sleeping curled up. Yang syndromes have internal heat and thirst; Yin syndromes have no thirst. Yang syndromes have closed bowels and bladder; Yin syndromes have clear and loose bowels and bladder. Abdominal pain and vomiting occur in both, but Yin pulse is deep and faint. Yang syndromes are mostly caused by wind, cold, summerheat, and dampness, originating from the Taiyang channel. Yin syndromes are mostly caused by diet, lifestyle, and emotions, originating from the Shaoyin channel. Thus, it is said that eight or nine out of ten cases of Shanghan involve internal injury; these are the primary diseases of Yin and Yang.
When Yin and Yang reach extremes, following treatment is not an error.
If Yang pathogen is not deep, it cannot cause cold extremities; if Yin pathogen is not severe, it cannot cause restlessness. This is "water extreme resembling fire, fire extreme resembling water," called reverse transformation, meaning extreme exuberance causes harm. Yang syndromes with tidal sweating, constipation, dark urine, fullness, thirst, mania, and delirium, or even petechiae, bleeding, and panting, may suddenly have heat concealed internally due to extreme heat, resulting in cold body and cold extremities, resembling Yin syndromes. However, although the body is cold, the patient does not desire warmth; although confused, the complexion is lustrous; the pulse is deep, slippery, and forceful. This is Yang extreme resembling Yin; treat with Da Chai Hu Tang (Major Bupleurum Decoction) for purgation, or Bai Hu Tang (White Tiger Decoction), or Zhu Ye Shi Gao Tang (Bamboo Leaf and Gypsum Decoction). Yin syndromes with cold extremities, vomiting, and diarrhea, no thirst, quietness, and curling up, or even sore throat and monotonous speech, may suddenly have fire floating externally due to extreme cold, causing restlessness and agitation, resembling Yang syndromes. However, although restless, the patient pulls clothes over their eyes; although mouth is dry and thirsty, they cannot swallow water; the pulse is deep, fine, and weak. This is Yin extreme resembling Yang; treat with Tong Mai Si Ni Tang (Pulse-Restoring Four Reversal Decoction). Following treatment involves counteracting treatment: taking warm medicine cold, cold medicine hot, warm medicine as sovereign with cool ministers, or cool medicine as sovereign with warm ministers. This is not as clearly erroneous as common physicians might think. If a heat disease is cured by warm medicine, it is because too much cold medicine was taken previously; if a cold disease is cured by cold medicine, it is because too much warm medicine was taken previously. Using cold to treat heat and warm to treat cold is called contrary treatment (Ni Zhi). Contrary treatment is actually correct treatment (Zheng Zhi). Who does not know the method of correct treatment?
When neither Exterior nor Interior is involved, do not attack the upper or lower.
Shanghan with headache, chills, and fever is Exterior. Loss of taste, abdominal discomfort, constipation or diarrhea is Interior. If after four or five days, or even thirteen days past the channel cycle, there are neither Exterior nor Interior signs, but slight fever remains, it is deficient heat; treat with Xiao Chai Hu Tang (Minor Bupleurum Decoction) to harmonize. Do not use sweating or emesis to damage the clear Qi of the Upper Jiao; do not use drastic purgation to damage the Stomach Qi of the Lower Jiao. If there is body heat, unclear vision, unresponsive pupils, and hard stool, then Da Chai Hu Tang or Xiao Cheng Qi Tang (Minor Order the Qi Decoction) can be used for purgation. If purgation has already been performed, the pulse is rapid, food is digested quickly, and there is no bowel movement for six or seven days, it is a blood stasis syndrome.
When both Exterior and Interior are present, examine which is less and which is more.
When Exterior and Interior signs coexist, determine their proportion before treating. Floating and large pulse indicates Exterior; vexation, thirst, and red urine indicate Interior; treat with Wu Ling San (Five-Ingredient Powder with Poria). Headache, body heat, and constipation indicate Interior; clear and free urination indicates Exterior; treat with Gui Zhi Tang (Cinnamon Twig Decoction). Chest fullness, loss of appetite, and constipation indicate Interior; aversion to cold and sweating on the head indicate Exterior; treat with Xiao Chai Hu Tang. If Taiyang disease is treated with premature purgation leading to協熱下利 (diarrhea with accompanying heat) and epigastric hardness, it is called unresolved Exterior and Interior; treat with Gui Zhi Ren Shen Tang (Cinnamon Twig and Ginseng Decoction). If premature purgation causes abdominal pain with accumulation, it is called Taiyang-Taiyin syndrome, or Interior transmitting to Exterior; treat with Gui Zhi Jia Shao Yao Tang (Cinnamon Twig Decoction plus Peony Root), adding Da Huang (Rhubarb) for severe cases. If premature purgation causes persistent diarrhea, hurried pulse, panting, and sweating, indicating the Exterior is not resolved, treat with Ge Gen Qin Lian Tang (Kudzu, Scutellaria, and Coptis Decoction). String-taut pulse with chest fullness: treat with Zhi Chi Tang (Gardenia and Fermented Soybean Decoction) via emesis. For predominantly Exterior, use Bai Hu Tang or combine with Xiao Chai Hu Tang. For predominantly Interior, use Wu Ling San or combine with Xiao Chai Hu Tang. For simultaneous urgency of Exterior and Interior, use Fang Feng Tong Sheng San (Saposhnikovia Decoction to Unblock the Whole Body) or Da Chai Hu Tang.
Misusing purgation when sweating is indicated leads to blood stasis, ao nao (restlessness), pi qi (stagnant qi), and jie xiong (chest binding).
For Taiyang syndrome with a floating-tight pulse, sweating is indicated. If sweating fails to resolve it, repeat sweating. If the opportunity to sweat is missed, the cold pathogen transmits through the channels; observe which channel it has entered and what disease has emerged. If sweating is indicated but purgation is mistakenly used, the exterior pathogen sinks inward due to deficiency, heat accumulates in the Interior, and transforms into blood stasis, ao nao, pi qi, jie xiong, and other syndromes.
Misusing sweating when purgation is indicated leads to palpitations, fright, loss of Yang, delirium, and exhaustion of cold extremities.
When Interior signs are complete and the pulse is deep and solid, purgation is indicated. If fever persists and the pulse remains unharmonized after purgation, assess deficiency and excess and purge again if necessary. If purgation is missed, the pathogen has no outlet. If purgation is indicated but sweating is mistakenly used, internal fluids are exhausted, transforming into palpitations and other syndromes.
Contraindications for sweating: all deficiencies, throat ulcers, strangury, bleeding disorders, ruined syndromes, moving Qi, wind-warmth, wind-dampness, and slow pulse.
Sweating is indicated when pulse and signs are entirely in the Exterior. However, if done too early or excessively, fluids are exhausted and complications arise. Contraindications include all deficiency consumptions with dry throat and mouth, sore throat and ulcers, strangury, menstruation just beginning, all hemorrhages, retching/coughing ruined syndromes, moving Qi around the umbilicus (up, down, left, right), wind-warmth, wind-dampness, damp-warmth, slow/fine/choppy pulse, or cold extremities with a tight pulse. These should be harmonized, not sweated. Forcing sweating in mild cases leads to difficult recovery; in severe cases, confusion and dizziness lead to death.
Contraindications for purgation: all deficiencies, throat swelling, vomiting, cold extremities, chest binding, moving Qi, floating/virtual pulse, and Exterior signs.
Purgation is indicated when pulse and signs are entirely in the Interior. However, if done too early or excessively, water and grain are depleted and complications arise. Contraindications include all deficiencies, throat swelling, vomiting, cold extremities, chest binding without passing gas, moving Qi around the umbilicus, fine/virtual/faint/choppy pulse, and Exterior signs like aversion to cold. Purgation here is dangerous; rescue with warm herbs as appropriate.
Yin deficiency with fire and rapid pulse: moxibustion is contraindicated as it consumes Yin.
Yin-Yang dual toxins, Shaoyin syndrome with vomiting and diarrhea, and mouth comfort with back aversion to cold and fine/choppy pulse belong to Yang deficiency and are suitable for moxibustion. Yin deficiency with fire and fine/rapid pulse is unsuitable for moxibustion. External fire aids internal fire; if fire blazes, the lower body becomes severely numb, bones burn, and flesh wastes away. This may lead to seminal emission, tidal cough, and hemoptysis, all caused by fire Qi. *Huo Ren* states: After moxibustion or burning needles, if symptoms resemble fire-pathogen mania, treat with Xiao Chai Hu Tang plus Long Gu (Dragon Bone) and Mu Li (Oyster Shell).
Cold in the diaphragm, cold extremities, and faint pulse: emesis is contraindicated as it causes death.
Cold fluid in the diaphragm with dry retching is a Shaoyin disease; cold extremities indicate Stomach deficiency; faint pulse indicates lower deficiency. Mistaken emesis causes internal vexation and damages Yuan Qi, potentially leading to untreatable conditions. If emesis is indicated but warming is used instead, toxic vapors stagnate in the Stomach, causing mania and other syndromes.
Urgent purgation to save Kidney Water: the opportunity to preserve fluids is critical.
In Shanghan, heat enters the Zang and flows into the Shaoyin channel, scorching the throat, causing dry mouth and thirst, indicating dried-up Kidney Water. In heat diseases, persistent heat with unresponsive eyes also indicates dried-up Kidney Water; both require urgent purgation to save Kidney Water. In Yangming, fever with profuse sweating, or sweating that fails to resolve the condition, abdominal fullness and pain, mania, delirium, and constipation all require urgent purgation to preserve Stomach fluids. In Shanghan, string-taut and slow pulse: taut indicates cold, slow indicates Zang involvement; large and tight pulse: large indicates Yang, tight indicates cold; both are called "Yang containing hidden Yin," requiring urgent purgation to differentiate Yin and Yang. Diarrhea with level pulses in all three positions and hardness under the heart indicates interior excess. Diarrhea with slow and slippery pulse, or large and floating pulse that feels choppy on pressure, with food aversion, indicates retained food in the Stomach. Retained food contraindicates croton seed (Ba Shuang); only Da Huang (Rhubarb) should be used to cleanse.
Urgent warming to harmonize Yang: its anti-emetic effect is significant.
Deep pulse with cold extremities, cold fluid in the diaphragm with dry retching, or occasional headache indicates attacking cold Qi; warm urgently with San Wei Can Yu Tang (Three-Ingredient Ginseng and Cornus Decoction). Extreme internal cold with cold extremities, vomiting, diarrhea, no thirst, quietness, curling up, impending loss of Yang-harmonizing Qi, and imperceptible pulses requires urgent warming with Si Ni Tang (Four Reversal Decoction). "Urgent" means the disease is severe and liable to change, unlike other diseases that can be treated slowly. Other examples: Taiyang non-stop sweating, aversion to wind after sweating, restlessness after sweating, palpitations and body pain—all require urgent addition of Fu Zi (Aconite) to Gui Zhi Tang (Cinnamon Twig Decoction) and Shao Yao (Peony Root). For Three Yang slow pulse and abdominal pain, Jian Zhong Tang (Build the Middle Decoction) should be applied first. Take one dose, stop when the disease is addressed; this applies to all Shanghan medicines.
After the channel cycle (unresolved), sweating and purgation should be mild.
Shanghan transmits through the channels in six days; it should resolve on the seventh day. If it continues beyond thirteen days without resolution, it is called "passing the channel." Improper sweating or purgation leaves pathogenic factors lingering, causing confusion, delirium, chest fullness, and tidal thirst. Adjust according to Exterior/Interior signs, possibly repeating mild sweating or purgation. Chaotic pulse with restlessness and sunken寸关尺 (cun, guan, chi) positions indicate danger. Slow pulse with peaceful sleep indicates residual pathogen and unrecovered Zheng Qi; treat with Shen Hu Shao Yao Tang (Ginseng, Bupleurum, and Peony Decoction). Diarrhea with harmonious pulse indicates previous purgation with pill medicine leaving residual heat. Qi deficiency after passing the channel, or mixed pathogenic factors, should be viewed alongside ruined syndromes.
Slow Chi pulse: temporary tonification is acceptable.
Slow and weak cun and chi pulses indicate blood deficiency. Regardless of initial wind-cold or miscellaneous diseases, sweating, emesis, and purgation are contraindicated. First use Xiao Jian Zhong Tang (Minor Build the Middle Decoction) or Huang Qi Jian Zhong Tang (Astragalus Build the Middle Decoction) to restore the pulse. If constitutionally robust, Xiao Chai Hu Tang is also good. Wait until the pulse is no longer slow before proceeding with treatment.
Formulas for releasing Exterior, attacking Interior, and warming Interior: the meaning of supporting Yang, assisting Yin, and suppressing Yin.
Here, Yin and Yang refer to Interior and Exterior. Disease represents deficiency; health represents excess. Exterior disease with Interior harmony means pathogen exits outward, resulting in Yang deficiency and Yin excess. Thus, releasing Exterior does not avoid heat, using pungent-sweet agents to support Yang. Interior disease with Exterior harmony means pathogen enters inward, resulting in Yin deficiency and Yang excess. Thus, attacking Interior does not avoid cold, using sour-bitter drugs to support Yin. If Yin channels directly receive cold pathogen, it is a Zang disease receiving Yin, with Yang Qi about to collapse; urgently use pungent-hot drugs to restore Yang and suppress Yin. Thus it is said: "Gui Zhi entering the throat, Yang excess leads to death; Cheng Qi entering the stomach, Yin excess leads to demise." Exaggerating excess and depleting deficiency, damaging the insufficient and benefiting the surplus—is killing by the physician. This is the key to sweating and purgation.
Methods value balance; insufficiency is better than excess.
Methods refer to sweating, emesis, purgation, warming, and harmonizing, each varying. Sweating includes heavy sweating to release Exterior and mild sweating to relieve muscles, distinguishing severity. Purgation includes urgent purgation, small doses, mild harmonizing, and draining, clarifying turbidity. Warming includes combined tonification. Emesis includes inducing vomiting and probing/guiding, or merely relieving fullness without daring to vomit. Harmonizing is singular. Some say Shanghan has no tonification method, as heat gains strength with tonification and requires further purgation, causing double distress; however, deficiency vexation, Interior cold, and Yin syndromes are exceptions. Balancing means the five methods hit the mark precisely; excess means rash advancement by crude practitioners; insufficiency means cautious slowness by intermediate practitioners. For Shanghan sweating/purgation drugs, stop after one dose if effective; do not finish the decoction, differing from miscellaneous diseases. Shanghan involves only sweating, emesis, and purgation; if used correctly, transmission is prevented. Success depends entirely on the physician's acuity and judgment.
Syndromes may seem similar yet be different; ignorance warrants abstaining from treatment.
When the Shanghan diagnosis is undecided, one may not know if wind-dampness, labor, phlegm, or food retention are concurrent. Similarity masking difference requires careful differentiation; thus, if unsure, it is better not to treat. Ban Gu said: "Not treating a disease yields a middle-class physician." One mistaken herb brings regret too late. Alas! Ancients used medicine to save lives from plague; today, medicine is used to sustain life. Sustaining life is good, but mistaking someone for death is akin to robbery! Be cautious! Be cautious!
The preceding paragraph discusses methods for Exterior/Interior, Yin/Yang, sweating, emesis, purgation, warming, and harmonizing.