吴又可曰。疫疠之邪。从口鼻而入。舍于伏脊之内。去表不远。附胃亦近。乃表里之
分界。即内经疟论所谓横连膜原者也。其热淫不正之气。本气充满者。或不受邪。
适有内因。便乘外因。感之浅者。或俟有触而发。若感之深者。中而即病也。其始阳
格于内。营卫营运之机。阻抑于表。遂觉凛凛恶寒。甚则四肢厥逆。至阳气困郁而
通。厥回而中外皆热。昏昧不爽。壮热自汗。此时邪伏膜原。纵使有汗。热不得解。必
俟伏邪已溃。表气潜行于内。精气自内达表。表里相通。振栗大汗。邪方外出。此名
战汗。脉静身凉而愈也。若伏邪未尽。必复发热。其热有久有浅。因所感之轻重也。
因元气之盛衰也。要皆始先恶寒。既而发热。至于发出。方显变证。其证或从外解。
或从内陷。外解则易。内陷则难。更有先后表里不同。有先表后里者。有先里后表
者。有但表而不复里者。有但里而不复表者。有表而里再表者。有里而表再里者。
有表里分传者。有表多于里者。有里多于表者。此为九传。从外解者。或发烦。或战
汗自汗。从内陷者。胸膈痞闷。心下胀满。腹中痛。燥结便秘。热结旁流。协热下利。或
呕吐恶心。谵语舌黄。及黑苔芒刺等证。因证用治。脉不浮不沉而数。昼夜皆热。日
晡益甚。头疼身痛。不可用辛热药汗之。又不可下。宜用达原饮。以透膜原之邪为
当也。若见各经。加入引各经药。不可执滞。感之轻者。舌苔亦薄。脉亦不甚数。如此
者。必从汗解。如不能得汗。邪气盘错于膜原。表里不相通达。未可强汗。衣被逼汗。
汤火劫汗也。感之重者。舌上苔如粉渍。药后反从内陷。舌根先黄。渐至中央。此邪
渐入胃也。前方用大黄下之。若脉长洪而数大汗多。此邪气适离膜原。欲表未表。
白虎汤证也。如舌上纯黄色。兼见里证。此邪已入胃。乃承气汤证也。有两三日即
离膜原者。有半月十日不传者。有初得之四五日。厌厌聂聂。至五六日。陡然势张
者。凡元气胜者。毒易传化。元气薄者。邪不易化。即不易传。故曰邪与元气。不两立
也。倘有他病久亏。适又感邪。能感而不能化。安望其传。不传则邪不去。淹留日久。
愈沉愈伏。因误进参、 。愈壅愈固。不死不休也。
达原饮
槟榔（二钱） 草果（五分） 浓朴（一钱） 知母（一钱）
芍药（一钱） 甘草（五分） 黄芩（一钱）
上七味。以水二钟。煎八分温服。
疫邪为病。有从战汗解者。有从自汗盗汗不解者。有无汗竟全归胃者。有自汗淋
漓。热渴反甚。终得战汗而解者。有胃气壅抑。必从下而得战汗解者。有汗解未尽。
越三四日前热复发者。有发黄因下。而复热发出斑者。有竟从发斑而愈者。有里
证急。虽有斑不愈者。此虽传变不常。要亦为常变也。又有局外之变者。男子适逢
使内。邪热乘虚陷于下焦。气道不施。以致小便淋塞。少腹胀满。至夜发热。以导赤
五苓散之类。分毫不效。与大承气一服。小便如注而愈。女子经水适来适断。失血
崩带。及心痛疝气。痰火喘哮。凡此皆非常变。大抵邪行如水。惟洼处受之。此妙喻
也。要之新疫而来旧病。但治其疫。他病自已也。
疫发一二日。舌上苔白如粉。早服达原饮一服。午后舌色变黄。随见胸膈满痛。大
渴烦燥。此伏邪之毒传里也。前方加大黄下之。烦热稍减。傍晚复加躁烦。发热通
舌变黑。刺生。鼻如烟煤。此邪毒最重。复合瘀胃。急投承气汤。抵暮大下。至夜半热
退。次早苔刺如失。一日有此三变。数日之法。一日行之。因其毒甚。故传变亦速。用
药不得不紧。设用缓剂。必无救矣。每见瘟疫二三日即死者。皆此类也。
疫病初起。脉虽数。未至洪大。其邪尚在膜原。宜达原饮。若误用白虎。既无破结之
能。但求清热。是犹扬汤止沸耳。邪入胃者。非承气不愈。误用白虎。既无夺邪之能。
徒伐胃气。反抑邪毒。致脉不行。反变细小。倘认阳证阴脉。妄言不治。因见脉微。复
不敢下。逡巡死耳。当此之际。惟急投承气汤。庶可救也。
疫发于半表半里。一定之法也。至于传变。出表入里。表里分传。俱未可定。医见有
表有里。乃引经论。先解其表。乃攻其里。此大谬也。尝见大剂麻黄。一毫无汗。转加
烦热者何耶。盖发汗者。以邪气在表。故用表药。即得宣其气而使之出也。今邪在
里。里气结滞。阳气不得即达于表。即四肢未免微厥。又安能气势蒸蒸而达乎外。
譬之水注。闭其后窍。则前窍不得涓滴。与此欲汗之义相类。故必承气解其里。里
气一通。不待发散。多有自汗而解者。其义可知也。设下后脉浮而微数。身微热。神
思不爽。此邪热浮于肌表。而里已无滞也。再与白虎汤。则余热复得清散。外即蒸
蒸汗解。仍此意也。若下后脉空而数。按之豁然如无。宜白虎加人参汤。覆杯即汗
解。下后脉数而浮。原当汗解。迁延五六日。脉证不改。仍不得汗者。以其反复数下。
致血液枯。正气微故也。用白虎加人参汤。以凉解中外。鼓舞元气。开泄腠理。即得
汗而解也。里证脉沉而数。当下之。下之当得汗解。脉改浮矣。今不得汗。二三日脉
更沉者。膜原之邪。仍瘀到胃也。更宜下之。或脉浮即与白虎汤。里证下后。热退身
凉。越几日复热者。非关饮食劳复。乃膜原之余邪复聚。医者不知。每归咎于病者
误也。仍下之为当。但制剂宜轻耳。
应下失下。口燥舌干而渴。身反热减。四肢时厥。欲得被近火。此阳气伏也。既下厥
回。脉大而数。舌上生津。不思水饮。此里邪去而郁阳暴伸也。宜柴胡清燥汤。去栝
蒌根、知母。加葛根。随其性而升泄之。
柴胡清燥汤
白芍药 当归 生地黄 陈皮 甘草 竹心 灯心 栝蒌根
知母 柴胡
上九味。水煎温服。
温病下后。二三日舌上复生苔刺。邪未尽也。再下之。苔刺虽去。而烦热未除。更下
之。热渴已减。日后更复热复苔者。更下之。不以数计。总之有是证。则用是药耳。医
者经历未到。中道生疑。往往失治。但其中有间日一下者。有连下三四日者。有下
二日间一日者。其后轻重缓急。有应用柴胡清燥汤者。有用犀角地黄汤者。至投
承气。何日多与少与。亦皆治法。苟或不明。亦足误事。然数下之证。亦仅见也。
疫病下后。脉证俱平。腹中有块。按之则痛。自觉有所阻而微闷。或时升降之气。往
来不利。常作蛙声。此邪气已尽。其宿结尚未除也。此不可攻。攻之陡损元气。须饮
食渐进。胃气渐复。津液润下。常见病疫愈。HT 粥半月。结块方下。坚黑如石者。又有
气促之病。过月余其块方消者。此又无形之结也。不可不知。
瘟疫下后。脉证俱平。大便十数日不行。时时作呕。此为下膈之证。盖下不能通。必
反于上。宜调胃承气汤热服。宿垢顿下。呕吐立止。慎不可补也。
凡疫邪贵乎早下。但见舌黄。心腹胀满。便可选用承气以驱其邪。乘人气血未乱。
津液未枯。投剂不致掣肘。勿拘下不厌迟之说也。且疫证之下。与伤寒异。伤寒必
俟结定而后攻。疫邪正欲驱热以为用。况疫气多湿。岂能即结。迁延不下。但蒸作
极臭如败酱。如藕泥。临死不结者多矣。
疫邪传里。遗热下焦。小便不利。邪无输泄。经气郁滞。其传为瘅。身目如金。宜茵陈
蒿汤。若用茵陈五苓散不效。此皆胃家移热。是以大黄为专功也。
茵陈蒿汤
茵陈蒿（二钱） 山栀子（一钱） 大黄（五钱） 水姜（三片）
上四味。以水一斗。先煮茵陈。减六升。内三味。煮取三升。去滓。分温三服。
疫邪在胸膈。满闷喜呕。腹不满。欲吐不吐。欲饮不饮。此邪与痰饮结滞也。宜瓜蒂散吐之。
瓜蒂散
胡瓜蒂（一钱） 赤小豆（一钱） 生栀仁（二钱）
上水煎。分二服。缓下。无瓜蒂。用淡豆豉二钱。
疫气留血分。里气壅闭。不下则斑不出。出则毒邪从外解矣。如下后斑渐出。更不
可下。设有下证。宜少与承气缓服。倘大下则元气不振。斑毒内陷则危。宜托里举
斑汤。如下后斑毒隐伏。反见循衣撮空脉微者。本方加人参三钱。得补发出者不死。
举斑汤
白芍药（一钱） 当归（一钱） 升麻（五分） 柴胡（七分）
白芷（七分） 穿山甲（二钱） 水姜（一片）
上七味。水煎温服。
疫病日久失下。自利纯臭水。昼夜十数行。口燥唇干舌裂。此热结旁流也。急下。以
大承气去其宿垢顿止。胃实失下。郁而为黄。热更不减。抟血为瘀。故经气不为热
郁。不致发黄。热邪不干血分。不致蓄血。同受其邪。故发黄而兼蓄血。非蓄血而致
发黄也。但蓄血一行。热随血泄。黄随泄减。故治黄茵陈蒿汤。治蓄血桃仁承气汤。
去桂枝、甘草。加牡丹皮、当归、芍药。
桃仁承气汤
桃仁（十八粒碎） 甘草（二钱） 大黄（四钱酒浸） 芒硝（二钱）
桂枝（二钱）
上水煎。热服。
胃移热于下焦气分。小便不利。热结膀胱也。若移热于下焦血分。膀胱蓄血也。夫蓄血证。
在小便利不利也。故昼日稍减。夜发热谵语者瘀血也。未行。桃仁承气下之。后用犀角地黄调之。
犀角地黄汤
地黄（一两） 赤芍药（二钱） 犀角（二钱镑） 牡丹皮（二钱）
上四味。以水二钟。煎八分。温服无时。
凡失下。以致循衣摸床。撮空肉惕。目不了了。邪热愈盛。元气将脱者。势不可竟下。
又不得不下。不得已用陶氏黄龙汤下之。（黄龙汤即大承气汤加甘草人参当归）因不下必死。当于
死中求生也。得下后用生脉散。加地黄、当归、白芍药、知母、陈皮、甘草。
疫病有首尾能食者。此邪不实于胃。切勿绝其饮食。但少少与之耳。
凡大下后调理。清燥养营汤。
清燥养营汤
知母 栝蒌根 当归 白芍药
生地黄 陈皮 甘草 灯心
上八味。水煎温服。
如表有余热。柴胡养营汤（即小柴胡去半夏人参加陈皮当归芍药浓朴生地黄大黄枳实生姜）
如有痰饮。胸膈不清者。宜栝贝养营汤。
栝贝养营汤
栝蒌根 贝母 栝蒌仁 苏子
橘红 白芍药 当归 知母 生姜
上九味。水煎温服。
舌苔。邪在膜原故白。在胃则黄。苔老则沉香色。白者不可下。黄者下。黑者急下。下
后苔不脱。舌刺舌裂。舌短舌硬舌卷。白沙苔。黑硬苔。皆当下。白苔滑泽。邪在膜原。
倘别有下证。宜达原饮加大黄。若大汗脉洪大而渴。白虎汤未可下也。惟目赤咽
干。气喷如火。小便黄赤。涓涓作痛。扬手掷足。脉沉数。下之无疑。有心下痛。腹胀满。
头痛。下之立止。初起未可下。如血液枯竭者为虚燥。宜导。
统论伤寒与时疫异同。夫伤寒必有感冒之因。恶风发寒。头痛身痛。发热而仍恶
寒。脉浮紧无汗。为伤寒。脉浮缓有汗。为中风。时疫初起。原无感冒之因。忽觉凛凛。
以后但热而不恶寒。然亦有所触而发者。或饥饱劳役。或焦思怒郁。皆能触动其
邪也。然不因有所触。而自发者居多。且伤寒投剂。一汗即解。时疫发散。虽汗不解。
伤寒不染。时疫能染。伤寒之邪。自毫窍入。时疫之邪。自口鼻入。伤寒感而即病。时
疫感而后发。伤寒汗解在前。时疫汗解在后。伤寒可使立汗。时疫俟其内溃。自汗
盗汗战汗。伤寒不发斑。时疫能发斑。伤寒感邪在经。以经传经。时疫感邪在内。邪
溢于经。经不自传。伤寒感发甚暴。时疫多有淹缠二三日。或渐加重。或至五六日。
忽然加重。伤寒初起。以发表为先。时疫初起。以疏利为主。其所同者。皆能传胃。至
是同归于一。故用承气导邪而出。故伤寒时疫。始异而终同也。伤寒之邪。自外传
内。原无根蒂。惟其传法。有进无退。故下之皆能病愈。时疫之发。始则匿于膜原。根
深蒂固。时发与营卫交并。客邪由经之处。营卫未有不被其伤者。故曰溃。然不溃
则不能传。不传则邪不能出。邪不出而疾不愈。乃时疫下后。多有不能即愈者何
耶。盖疫邪多有表里分传者。因有一半向外。邪传留于肌肉。一半向里。邪传留于
胃家。惟传于胃。故里气结滞。里结表气因亦不通。于是肌肉之邪。不得即达于肌
表。下后里气一通。表气亦顺。向郁肌肉者。方能尽达于表。或斑或汗。然后可以谋
治而愈。伤寒下后。无有此法。虽曰终同。实不同也。
凡阳证似阴者。伤寒与瘟疫多有之。其阴证似阳者。正伤寒有之。温疫必无此证。
宜辨之。夫阳证似阴。外虽寒而内有热。故小便必赤涩。若阴证似阳者。格阳之证
也。上热下寒。故小便清白。但以小便赤白为据。万不失一。
凡四损不可治。大劳大欲。大病久病后。气血俱虚。阴阳并竭。正气先亏。邪气自陷也。
夫人疫发。见证或轻。虽有头疼身热自汗。而饮食不绝。力可徒步。又乌知其疫也。
况脉又不浮不沉而数。病患无处追求。每每妄诉病情。医家不辨是非。便引东垣
吴又可说：疫疠之邪，从口鼻而入，潜伏于伏脊之内（指脊柱深处，即膜原部位），距离体表不远，依附于胃腑也很近，这是表里之间的分界区域。这正是《内经·疟论》所说的“横连膜原”的意思。那些热毒炽盛的不正之气，如果人体正气充足，或许不会受邪；若恰好有内因（如饮食劳倦等），便乘虚结合外因致病。感受较浅的，或许要等到有触动才发作；若感受深重的，则中邪后立即发病。
起初阳气被格拒于内，营卫运行的机制在体表受到阻抑，于是感到凛凛恶寒，甚至四肢厥冷。直到阳气困郁而通达，厥逆回退，内外都发热，神志昏昧不清，壮热自汗。此时邪气潜伏在膜原，即使有汗，热也不能解除，必须等到伏邪溃散，表气潜行入内，精气由内达表，表里相通，出现振栗大汗，邪气方才外出。这叫做“战汗”，脉象平静、身体凉爽后痊愈。如果伏邪未尽，必定再次发热。热的程度有深有浅，取决于感邪的轻重和元气的盛衰。总之都是先恶寒，继而发热，到了发出阶段，才显现出变证。其证候有的从外表解，有的从内陷。外解则容易，内陷则困难。更有先后表里不同的情况，有先表后里的，有先里后表的，有只见表证不再见里证的，有只见里证不再见表证的，有表证之后又见表证的，有里证之后又见里证的，有表里同时传变的，有表证多于里证的，有里证多于表证的。这称为“九传”。
从外表解的，或出现烦躁，或战汗、自汗而解。从内陷的，胸膈痞闷，心下胀满，腹中痛，燥结便秘，热结旁流（燥屎内结而水液旁流），协热下利，或呕吐恶心，谵语舌黄，以及黑苔芒刺等证候。根据证候进行治疗，脉象不浮不沉而数，昼夜皆热，日晡（下午3-5点）加重，头疼身痛，不可用辛热药发汗，也不可用攻下药，宜用达原饮，以透达膜原之邪为当。如果见到各经的症状，加入引经药即可，不可固执拘泥。
感邪轻的，舌苔也薄，脉象也不甚数，这样的人，必定从汗解。如果不能得汗，说明邪气盘踞在膜原，表里不相通达，不可强行发汗。那种衣服逼汗、汤火劫汗的方法，是错误的。感邪重的，舌上苔如粉渍状，服药后反而从内陷，舌根先黄，渐至中央，这是邪气逐渐进入胃腑。前方用大黄攻下。如果脉长洪而数，大汗多，这是邪气刚刚离开膜原，想要外达但尚未完全外达，属于白虎汤证。如果舌上纯黄色，兼见里证，这是邪气已入胃，属于承气汤证。
有两三天就离开膜原的，有半月十日不传变的，有初得病四五日，症状轻微，到五六日突然势张的。凡是元气胜者，毒邪容易传化；元气薄弱者，邪气不易传化，即不易传变。所以说邪气与元气是不两立的。如果有其他疾病久亏，又适逢感邪，能感邪而不能化，怎能指望它传变？不传变则邪气不去，淹留日久，愈沉愈伏，如果误进人参、黄芪等补药，愈壅滞坚固，不死不休。
达原饮
槟榔（二钱） 草果（五分） 浓朴（一钱） 知母（一钱）
芍药（一钱） 甘草（五分） 黄芩（一钱）
以上七味药，用水二钟，煎至八分，温服。
疫邪致病，有从战汗解的，有从自汗盗汗不解的，有无汗竟全归胃的，有自汗淋漓，热渴反而加重，最终通过战汗而解的，有胃气壅抑，必须通过攻下才能战汗而解的，有汗解未尽，过了三四天前热复发的，有发黄因攻下，而复热发出斑的，有竟从发斑而愈的，有里证急迫，虽有斑也不愈的。这些虽然传变无常，但也属于常变之中。又有局外的变证，男子适逢房事，邪热乘虚陷入下焦，气道不通，导致小便淋涩闭塞，少腹胀满，夜间发热，用导赤散、五苓散之类，分毫不效，给予大承气汤一服，小便如注而愈。女子经期适来或适断，失血崩带，及心痛疝气，痰火喘哮，凡此皆是非常变证。大抵邪气运行如水，只在洼处聚集，这是巧妙的比喻。总之新来的疫病并发旧病，只需治疗疫病，其他病自然痊愈。
疫病发作一二日，舌上苔白如粉，早晨服用达原饮一服，午后舌色变黄，随即出现胸膈满痛，大渴烦躁，这是伏邪之毒传里。前方加大黄攻下，烦热稍减，傍晚又加躁烦，发热通舌变黑，生刺，鼻如烟煤，这是邪毒最重，复合瘀胃，急投承气汤，至暮时大下，至夜半热退，次早苔刺消失。一天内有这三种变化，几天的治法，一天完成。因为毒邪很盛，所以传变也快，用药不得不紧。如果用缓剂，必无救矣。每见瘟疫二三日即死的，都是这类情况。
疫病初起，脉虽数，未至洪大，邪气尚在膜原，宜用达原饮。如果误用白虎汤，既无破结的能力，只求清热，这犹如扬汤止沸。邪入胃者，非承气汤不能愈。误用白虎汤，既无夺邪的能力，徒然伐伤胃气，反而抑制邪毒，导致脉象不行，反变细小。如果认作阳证阴脉，妄言不治，因为见到脉微，又不敢攻下，犹豫不决而死。当此之际，只有急投承气汤，才可以挽救。
疫邪发于半表半里，是固定的规律。至于传变，出表入里，表里分传，都未可定。医生见有表有里，便引用经论，先解其表，再攻其里，这是大错。曾见用大剂量麻黄，一毫无汗，反而加重烦热，为什么呢？因为发汗是因为邪气在表，所以用表药，宣发其气使之外出。现在邪在里，里气结滞，阳气不能立即到达体表，所以四肢未免微厥，又怎么能气势蒸蒸而达于外呢？譬如注水，闭住后窍，前窍不得涓滴，这与欲汗的道理相似。所以必须用承气汤解其里，里气一通，不待发散，多有自汗而解的。道理可知。如果下后脉浮而微数，身微热，神思不爽，这是邪热浮于肌表，而里已无滞。再给白虎汤，则余热得以清散，外面即蒸蒸汗解，仍是这个意思。如果下后脉空而数，按之豁然如无，宜用白虎加人参汤，覆杯即汗解。下后脉数而浮，原应当汗解，迁延五六日，脉证不改，仍不得汗，是因为反复多次攻下，导致血液枯竭，正气微弱。用白虎加人参汤，以凉解中外，鼓舞元气，开泄腠理，即可得汗而解。里证脉沉而数，当下之。下之应当得汗解，脉改浮。现在不得汗，二三日脉更沉，是膜原之邪，仍瘀阻到胃。更宜下之。或者脉浮即给白虎汤。里证下后，热退身凉，过了几天又发热，不是关饮食劳复，而是膜原之余邪复聚。医者不知，每每归咎于病人误治。仍以下之为当，但制剂宜轻。
应下而未下，口燥舌干而渴，身反热减，四肢时厥，欲得被近火，这是阳气伏匿。既然下后厥回，脉大而数，舌上生津，不思水饮，这是里邪去而郁阳暴伸。宜用柴胡清燥汤，去掉栝蒌根、知母，加葛根，随其性而升泄之。
柴胡清燥汤
白芍药 当归 生地黄 陈皮 甘草 竹心 灯心 栝蒌根
知母 柴胡
以上九味药，水煎温服。
温病下后，二三日舌上再生苔刺，邪气未尽。再下之。苔刺虽去，而烦热未除，更下之。热渴已减，日后更复热复苔者，更下之。不以次数计。总之有是证，则用是药。医者经历未到，中途生疑，往往失治。但其中有间日一下的，有连下三四日的，有下二次间一日一次的。其后轻重缓急，有用柴胡清燥汤的，有用犀角地黄汤的。至于投承气汤，何日多与少与，也都是治法。如果不明白，也足以误事。然而数下的证候，也只见于此类。
疫病下后，脉证俱平，腹中有块，按之则痛，自觉有所阻而微闷，或时升降之气，往来不利，常作蛙声，这是邪气已尽，其宿结尚未除也。此不可攻，攻之陡损元气。须饮食渐进，胃气渐复，津液润下，常见病疫愈。喝粥半月，结块方下。坚黑如石者，又有气促之病，过月余其块方消者，这又是无形之结。不可不知。
瘟疫下后，脉证俱平，大便十数日不行，时时作呕，此为下膈之证。盖下不能通，必反于上，宜调胃承气汤热服。宿垢顿下，呕吐立止。慎不可补也。
凡疫邪贵乎早下。但见舌黄，心腹胀满，便可选用承气以驱其邪。乘人气血未乱，津液未枯，投剂不致掣肘。勿拘“下不厌迟”之说。且疫证之下，与伤寒异。伤寒必俟结定而后攻，疫邪正欲驱热以为用，况疫气多湿，岂能即结。迁延不下，但蒸作极臭如败酱，如藕泥，临死不结者多矣。
疫邪传里，遗热下焦，小便不利，邪无输泄，经气郁滞，其传为瘅（疸），身目如金，宜茵陈蒿汤。若用茵陈五苓散不效，此皆胃家移热，是以大黄为专功也。
茵陈蒿汤
茵陈蒿（二钱） 山栀子（一钱） 大黄（五钱） 水姜（三片）
以上四味药，用水一斗，先煮茵陈，减六升，内三味，煮取三升，去滓，分温三服。
疫邪在胸膈，满闷喜呕，腹不满，欲吐不吐，欲饮不饮，这是邪与痰饮结滞。宜瓜蒂散吐之。
瓜蒂散
胡瓜蒂（一钱） 赤小豆（一钱） 生栀仁（二钱）
以上用水煎，分二服，缓下。无瓜蒂，用淡豆豉二钱。
疫气留血分，里气壅闭，不下则斑不出，出则毒邪从外解矣。如下后斑渐出，更不可下。设有下证，宜少与承气缓服。倘大下则元气不振，斑毒内陷则危。宜托里举斑汤。如下后斑毒隐伏，反见循衣撮空、脉微者，本方加人参三钱，得补发出者不死。
举斑汤
白芍药（一钱） 当归（一钱） 升麻（五分） 柴胡（七分）
白芷（七分） 穿山甲（二钱） 水姜（一片）
以上七味药，水煎温服。
疫病日久失下，自利纯臭水，昼夜十数行，口燥唇干舌裂，这是热结旁流。急下，以大承气去其宿垢顿止。胃实失下，郁而为黄，热更不减，抟血为瘀，故经气不为热郁，不致发黄。热邪不干血分，不致蓄血。同受其邪，故发黄而兼蓄血，非蓄血而致发黄也。但蓄血一行，热随血泄，黄随泄减。故治黄茵陈蒿汤，治蓄血桃仁承气汤，去桂枝、甘草，加牡丹皮、当归、芍药。
桃仁承气汤
桃仁（十八粒碎） 甘草（二钱） 大黄（四钱酒浸） 芒硝（二钱）
桂枝（二钱）
以上水煎，热服。
胃移热于下焦气分，小便不利，热结膀胱也。若移热于下焦血分，膀胱蓄血也。夫蓄血证，在小便利不利也。故昼日稍减，夜发热谵语者瘀血也。未行，桃仁承气下之。后用犀角地黄调之。
犀角地黄汤
地黄（一两） 赤芍药（二钱） 犀角（二钱镑） 牡丹皮（二钱）
以上四味药，用水二钟，煎八分，温服无时。
凡失下，以致循衣摸床，撮空肉惕，目不了了，邪热愈盛，元气将脱者，势不可竟下。又不得不下。不得已用陶氏黄龙汤下之。（黄龙汤即大承气汤加甘草人参当归）因不下必死，当于死中求生也。得下后用生脉散，加地黄、当归、白芍药、知母、陈皮、甘草。
疫病有首尾能食者，此邪不实于胃，切勿绝其饮食。但少少与之耳。
清燥养营汤
知母 栝蒌根 当归 白芍药
生地黄 陈皮 甘草 灯心
以上八味药，水煎温服。
如表有余热，柴胡养营汤（即小柴胡去半夏人参加陈皮当归芍药浓朴生地黄大黄枳实生姜）。
如有痰饮，胸膈不清者，宜栝贝养营汤。
栝贝养营汤
栝蒌根 贝母 栝蒌仁 苏子
橘红 白芍药 当归 知母 生姜
以上九味药，水煎温服。
舌苔，邪在膜原故白，在胃则黄。苔老则沉香色。白者不可下，黄者下，黑者急下。下后苔不脱，舌刺舌裂，舌短舌硬舌卷，白沙苔，黑硬苔，皆当下。白苔滑泽，邪在膜原。倘别有下证，宜达原饮加大黄。若大汗脉洪大而渴，白虎汤未可下也。惟目赤咽干，气喷如火，小便黄赤，涓涓作痛，扬手掷足，脉沉数，下之无疑。有心下痛，腹胀满，头痛，下之立止。初起未可下，如血液枯竭者为虚燥，宜导。
统论伤寒与时疫异同。夫伤寒必有感冒之因，恶风发寒，头痛身痛，发热而仍恶寒，脉浮紧无汗，为伤寒。脉浮缓有汗，为中风。时疫初起，原无感冒之因，忽觉凛凛，以后但热而不恶寒。然亦有所触而发者，或饥饱劳役，或焦思怒郁，皆能触动其邪也。然不因有所触，而自发者居多。且伤寒投剂，一汗即解，时疫发散，虽汗不解。伤寒不染，时疫能染。伤寒之邪，自毫窍入，时疫之邪，自口鼻入。伤寒感而即病，时疫感而后发。伤寒汗解在前，时疫汗解在后。伤寒可使立汗，时疫俟其内溃，自汗盗汗战汗。伤寒不发斑，时疫能发斑。伤寒感邪在经，以经传经，时疫感邪在内，邪溢于经，经不自传。伤寒感发甚暴，时疫多有淹缠二三日，或渐加重，或至五六日，忽然加重。伤寒初起，以发表为先，时疫初起，以疏利为主。其所同者，皆能传胃，至是同归于一，故用承气导邪而出。故伤寒时疫，始异而终同也。伤寒之邪，自外传内，原无根蒂，惟其传法，有进无退，故下之皆能病愈。时疫之发，始则匿于膜原，根深蒂固，时发与营卫交并，客邪由经之处，营卫未有不被其伤者，故曰溃。然不溃则不能传，不传则邪不能出，邪不出而疾不愈。乃时疫下后，多有不能即愈者何耶？盖疫邪多有表里分传者，因有一半向外，邪传留于肌肉，一半向里，邪传留于胃家。惟传于胃，故里气结滞，里结表气因亦不通，于是肌肉之邪，不得即达于肌表。下后里气一通，表气亦顺，向郁肌肉者，方能尽达于表，或斑或汗，然后可以谋治而愈。伤寒下后，无有此法，虽曰终同，实不同也。
凡阳证似阴者，伤寒与瘟疫多有之。其阴证似阳者，正伤寒有之，温疫必无此证，宜辨之。夫阳证似阴，外虽寒而内有热，故小便必赤涩。若阴证似阳者，格阳之证也。上热下寒，故小便清白。但以小便赤白为据，万不失一。
凡四损不可治，大劳大欲，大病久病后，气血俱虚，阴阳并竭，正气先亏，邪气自陷也。夫人疫发，见证或轻，虽有头疼身热自汗，而饮食不绝，力可徒步，又乌知其疫也。况脉又不浮不沉而数，病患无处追求，每每妄诉病情，医家不辨是非，便引东垣
Wu Youke stated: The pathogenic factor of epidemic pestilence enters through the mouth and nose, and lodges within the "Fu Ji" (deep area along the spine, referring to the Mo Yuan/Membrane Source). It is not far from the exterior, yet close to the Stomach, marking the boundary between the interior and exterior. This corresponds to what the *Nei Jing* (Inner Canon) in the *Malaria Treatise* calls "horizontally connecting the Mo Yuan." The abnormal heat-inducing qi, if the body's original qi is sufficient, may not be affected. However, if there are internal factors present, it combines with external factors to cause disease. Those who contract a mild infection may only develop symptoms upon being triggered, whereas those with severe contraction fall ill immediately.
Initially, Yang Qi is blocked internally, and the mechanism of Ying and Wei circulation is obstructed at the exterior, leading to chills and aversion to cold, even to the point of cold limbs. Only when the constrained Yang Qi becomes unblocked do the cold limbs recede, resulting in fever throughout the body and mind, confusion, high fever with spontaneous sweating. At this stage, the pathogen lies hidden in the Mo Yuan. Even if sweating occurs, the heat cannot resolve until the hidden pathogen dissipates, the exterior qi moves inward, and the essence qi reaches the exterior from within, allowing communication between interior and exterior. This leads to shivering and profuse sweating, after which the pathogen exits outward. This is called "Zhan Han" (Battle Sweat), followed by a calm pulse and cool body indicating recovery. If the hidden pathogen remains, fever will recur. The depth and duration of fever depend on the severity of the infection and the strength of the original qi. Generally, it starts with chills, followed by fever, and only manifests as transformed patterns when emerging. The patterns may resolve from the exterior or sink into the interior. Resolution from the exterior is easier; sinking into the interior is difficult. There are various sequences of exterior and interior transmission: exterior then interior, interior then exterior, exterior only without returning to interior, interior only without returning to exterior, exterior followed by repeated exterior, interior followed by repeated interior, simultaneous exterior-interior transmission, more exterior than interior, and more interior than exterior. These are known as the "Nine Transmissions."
Resolution from the exterior may involve irritability, battle sweat, or spontaneous sweating. Sinking into the interior presents with chest and diaphragm fullness and oppression, epigastric distension, abdominal pain, dry constipation, heat-binding with peripheral flow (dry stool impaction with liquid leakage), diarrhea with heat, vomiting, nausea, delirium, yellow tongue coating, black coating with prickles, and other signs. Treatment should be based on the pattern. The pulse is neither floating nor deep but rapid, with fever day and night, worsening in the late afternoon (Shen hour). Headache and body ache are present. Acrid-hot herbs for sweating should not be used, nor purgatives. Instead, Da Yuan Yin (Reach the Origin Decoction) should be used to penetrate the Mo Yuan pathogen. If symptoms of specific meridians appear, add guiding herbs accordingly, avoiding rigid adherence.
For mild infections, the tongue coating is thin, and the pulse is not very rapid. Such cases must resolve through sweating. If sweating does not occur, it indicates the pathogen is entrenched in the Mo Yuan, blocking interior-exterior communication. Forced sweating via clothing or hot baths is incorrect. For severe infections, the tongue coating resembles powder stain. After medication, the pathogen may sink inward; the root of the tongue turns yellow first, spreading to the center, indicating the pathogen entering the Stomach. Use Rhubarb (Da Huang) in the previous formula to purge. If the pulse is long, surging, and rapid with profuse sweating, the pathogen has just left the Mo Yuan and desires to exit but has not fully done so; this is a Bai Hu Tang (White Tiger Decoction) pattern. If the tongue is purely yellow with interior signs, the pathogen has entered the Stomach; this is a Cheng Qi Tang (Order the Qi Decoction) pattern. Some leave the Mo Yuan in two to three days; some remain unchanged for ten to fifteen days; some show mild symptoms for four to five days, then suddenly intensify on the fifth or sixth day. Those with strong original qi transform pathogens easily; those with weak original qi do not. Thus, pathogen and original qi are incompatible. If pre-existing deficiency exists alongside new infection, transformation and transmission may fail. Without transmission, the pathogen remains, lingering longer and sinking deeper. Mistaken use of Ginseng (Ren Shen) or Astragalus (Huang Qi) causes stagnation and consolidation, potentially fatal.
**Da Yuan Yin (Reach the Origin Decoction)**
Betel Nut (Bing Lang, 2 qian), Caoguo (Tsao-ko Fruit, 0.5 qian), Magnolia Bark (Nou Pu, 1 qian), Anemarrhena (Zhi Mu, 1 qian), Peony (Shao Yao, 1 qian), Licorice (Gan Cao, 0.5 qian), Scutellaria (Huang Qin, 1 qian).
Seven ingredients. Decoct in 2 cups of water to 0.8 cup, take warm.
Epidemic pathogens cause disease resolving via battle sweat, spontaneous/night sweat without resolution, no sweat leading entirely to the Stomach, profuse sweat with worsening thirst/heat resolving finally via battle sweat, Stomach Qi stagnation requiring purgation to achieve battle sweat, incomplete sweat resolution with recurrence after 3-4 days, jaundice due to purgation followed by heat and macules, resolution solely via macules, urgent interior patterns where macules do not indicate cure. Although variable, these are common transformations. External variations include men engaging in intercourse during illness, allowing heat to sink to the Lower Jiao, causing urinary obstruction, lower abdominal fullness, and night fever. Dao Chi San and Wu Ling San are ineffective; Da Cheng Qi Tang cures it. Women with irregular menstruation, hemorrhage, leukorrhea, heart pain, hernia, phlegm-fire asthma, etc., represent unusual variations. Pathogens move like water, settling in depressions. New epidemics superimposed on old diseases require treating the epidemic alone; other conditions resolve spontaneously.
On days 1-2 of epidemic onset, white powder-like tongue coating suggests morning dose of Da Yuan Yin. By afternoon, yellow coating, chest/diaphragm pain, extreme thirst, and irritability indicate pathogen toxin transmitting inward. Add Rhubarb to purge. Irritability decreases slightly, but worsens by evening with black tongue and prickles, nose resembling coal smoke, indicating severe toxin combined with stomach stasis. Urgently administer Cheng Qi Tang. Profuse stool passage by nightfall resolves fever by midnight. Tongue prickles disappear next morning. Three changes in one day compress several days' treatment due to intense toxicity and rapid transmission. Slow remedies fail. Many die within 2-3 days from such cases.
Early epidemic pulse is rapid but not surging-large; pathogen remains in Mo Yuan. Use Da Yuan Yin. Mistaken use of Bai Hu Tang lacks breaking power and only clears heat, like stirring boiling water. Pathogen in Stomach requires Cheng Qi Tang. Mistaken Bai Hu Tang damages Stomach Qi and suppresses toxin, making pulse imperceptible or fine. Do not mistake Yang pattern for Yin pulse and declare incurable. Hesitation due to faint pulse leads to death. Urgent Cheng Qi Tang is the only salvation.
Epidemic pathology originates in half-exterior/half-interior. Transmission direction is unpredictable. Physicians seeing both exterior and interior signs may wrongly treat exterior first, then interior. Using large doses of Ephedra (Ma Huang) yields no sweat and increases irritability because sweating targets exterior pathogens. Here, pathogen is interior, causing Qi stagnation preventing Yang from reaching the surface, hence cold limbs. Like closing the rear outlet stops front flow, sweating is impossible. Purge interior with Cheng Qi Tang first. Once interior Qi flows, spontaneous sweating often resolves the condition. If post-purge pulse is floating-mildly rapid with slight fever and mental cloudiness, heat floats on muscle layer while interior is clear. Re-administer Bai Hu Tang to clear residual heat, leading to steaming sweat resolution. If post-purge pulse is empty-rapid and hollow, use Bai Hu Tang plus Ginseng for immediate sweat resolution. If post-purge pulse is rapid-floating, sweating should occur; if delayed 5-6 days without sweat due to repeated purging depleting blood and weakening Zheng Qi, use Bai Hu Tang plus Ginseng to cool interior/exterior, boost Qi, open pores, and induce sweat. Interior pattern with deep-rapid pulse requires purging; expect sweat and floating pulse afterward. If no sweat and pulse deepens after 2-3 days, Mo Yuan pathogen still blocks Stomach; purge again. If pulse floats, give Bai Hu Tang. If fever returns days after interior purgation and cooling, not due to diet/labor relapse, but re-aggregation of residual Mo Yuan pathogen, purge again with lighter dosage.
Failure to purge when indicated leads to dry mouth/tongue/thirst, reduced body heat, intermittent cold limbs, desire for warmth, indicating hidden Yang. Post-purge, cold limbs return, pulse large-rapid, tongue moist, no thirst, indicating interior pathogen gone and constrained Yang expands. Use Chai Hu Qing Zao Tang, removing Trichosanthes Root (Gua Lou Gen) and Anemarrhena (Zhi Mu), adding Kudzu (Ge Gen) to ascend and vent.
**Chai Hu Qing Zao Tang (Bupleurum Clearing Dryness Decoction)**
Peony (Bai Shao Yao), Angelica (Dang Gui), Rehmannia (Sheng Di Huang), Tangerine Peel (Chen Pi), Licorice (Gan Cao), Bamboo Heart (Zhu Xin), Juncus (Deng Xin), Trichosanthes Root (Gua Lou Gen), Anemarrhena (Zhi Mu), Bupleurum (Chai Hu).
Nine ingredients. Decoct in water, take warm.
Post-purge warm disease shows tongue prickles again after 2-3 days, indicating remaining pathogen. Purge again. If prickles go but irritability/heat persist, purge again. If heat/thirst decrease but recur later, purge again. Countless purges may be needed. Treat according to pattern. Inexperienced physicians hesitate, causing missed treatments. Regimens vary: every other day, consecutive days, or alternating. Later stages may require Chai Hu Qing Zao Tang or Xi Jiao Di Huang Tang. Dosage of Cheng Qi Tang varies by method. Failure to understand leads to error. Multiple purges are rare.
Post-epidemic purgation with normalized pulse/symptoms but abdominal mass, tenderness, obstruction sensation, poor Qi movement, and frog-like sounds indicate exhausted pathogen but retained accumulation. Do not attack; this damages Qi. Gradual diet restores Stomach Qi and fluids. Boiling congee for half a month dissolves masses. Hard black stones may take over a month to dissolve if associated with shortness of breath. This is formless accumulation; note this.
Post-plague purgation with normalized pulse/symptoms but 10+ days constipation and occasional vomiting indicates Lower Ge syndrome. Downward blockage forces reflux upward. Administer Tiao Wei Cheng Qi Tang hot. Accumulation passes, vomiting stops. Do not tonify.
Epidemic pathogens benefit from early purging. Yellow tongue, epigastric/abdominal fullness warrant Cheng Qi Tang to expel pathogen while Qi/Blood/Fluids are intact. Ignore "purging is never too late" dogma. Plague purging differs from Cold Damage. Cold Damage waits for solidification before attacking; plague pathogens use heat for action and often involve dampness, resisting quick solidification. Delayed purging results in foul-smelling putrid matter.
Pathogen transmitting inward leaving heat in Lower Jiao causes difficult urination, stagnant channel Qi, transforming into Jaundice (Dan). Body/eyes turn golden. Use Yin Chen Hao Tang. If Yin Chen Wu Ling San fails, heat transferred from Stomach requires Rhubarb's specific action.
**Yin Chen Hao Tang (Artemisia Capillaris Decoction)**
Artemisiae Scopariae Herba (Yin Chen Hao, 2 qian), Gardenia (Shan Zhi Zi, 1 qian), Rhubarb (Da Huang, 5 qian), Ginger (Sheng Jiang, 3 slices).
Four ingredients. Decoct in 10 cups, boil Artemisia first to reduce by 6 cups, add others, boil to 3 cups, strain, divide into 3 warm doses.
Pathogen in Chest/Diaphragm causes fullness, desire to vomit, non-distended abdomen, inability to vomit/drink. Pathogen-phlegm fluid stagnation. Use Gua Di San to induce vomiting.
**Gua Di San (Melon Seed Powder)**
Melon Seeds (Hu Gua Di, 1 qian), Red Adzuki Bean (Chi Xiao Dou, 1 qian), Gardenia Kernel (Sheng Zhi Ren, 2 qian).
Decoct in water, divide into 2 doses, slow purge. Substitute with Fermented Soybean (Dan Dou Chi, 2 qian) if unavailable.
Pathogen lingering in Blood level, interior Qi blocked. No purging means no macules; emergence allows toxin exit externally. Post-purge gradual macule emergence contraindicates further purging. If purgation signs exist, give small amounts of Cheng Qi Tang slowly. Heavy purging weakens Qi, risking macule toxin sinking inward (critical). Use Tuo Li Ju Ban Tang. If post-purge macules hide with finger-picking/pulselessness, add 3 qian Ginseng to original formula to boost and emit; survival possible.
**Ju Ban Tang (Macule Elevation Decoction)**
Peony (Bai Shao Yao, 1 qian), Angelica (Dang Gui, 1 qian), Cimicifuga (Sheng Ma, 0.5 qian), Bupleurum (Chai Hu, 0.7 qian), Angelica Dahurica (Bai Zhi, 0.7 qian), Pangolin Scale (Chuan Shan Jia, 2 qian), Ginger (Sheng Jiang, 1 slice).
Seven ingredients. Decoct in water, take warm.
Long-standing untreated epidemic with pure foul watery diarrhea 10+ times/day, dry mouth/lips/cracked tongue indicates Heat-Binding with Peripheral Flow. Urgent purging with Da Cheng Qi Tang removes accumulation, stopping diarrhea. Stomach excess untreated leads to yellowing; persistent heat coagulates blood into stasis. Channel Qi not heat-constrained prevents jaundice; Heat not affecting Blood level prevents Blood Stasis. Both can occur together (Jaundice + Blood Stasis), not Stasis causing Jaundice. Once Blood Stasis moves, heat drains with blood, jaundice fades. Treat Jaundice with Yin Chen Hao Tang; Treat Blood Stasis with Tao Ren Cheng Qi Tang, removing Cinnamon Twig (Gui Zhi) and Licorice (Gan Cao), adding Moutan (Mu Dan Pi), Angelica (Dang Gui), Peony (Shao Yao).
**Tao Ren Cheng Qi Tang (Peach Kernel Order the Qi Decoction)**
Peach Kernel (Tao Ren, 18 crushed), Licorice (Gan Cao, 2 qian), Rhubarb (Da Huang, 4 qian wine-soaked), Mirabilite (Mang Xiao, 2 qian), Cinnamon Twig (Gui Zhi, 2 qian).
Decoct in water, take hot.
Stomach heat transferring to Lower Jiao Qi level causes difficult urination (Heat binding Bladder). Transfer to Blood level causes Bladder Blood Stasis. Differentiation lies in urination. Daytime slight relief, night fever/delirium indicates Blood Stasis. Unmoved? Purge with Tao Ren Cheng Qi Tang. Follow with Xi Jiao Di Huang Tang for regulation.
**Xi Jiao Di Huang Tang (Rhinoceros Horn Rehmannia Decoction)**
Rehmannia (Di Huang, 1 liang), Red Peony (Chi Shao Yao, 2 qian), Rhinoceros Horn (Xi Jiao, 2 qian shaved), Moutan (Mu Dan Pi, 2 qian).
Four ingredients. Decoct in 2 cups to 0.8 cup, take warm anytime.
Failure to purge leads to picking clothes, grasping at air, muscle twitching, unclear vision, increasing pathogen heat, impending Qi collapse. Cannot simply purge heavily, yet must purge. Use Tao Shi's Huang Long Tang (Da Cheng Qi Tang plus Licorice, Ginseng, Angelica) to save life from death. Post-purge, use Sheng Mai San plus Rehmannia, Angelica, Peony, Anemarrhena, Tangerine Peel, Licorice.
Epidemics where patient eats well throughout indicate pathogen not solidifying in Stomach. Do not restrict food; offer small amounts frequently.
Post-heavy purging regulation uses Qing Zao Yang Ying Tang.
**Qing Zao Yang Ying Tang (Clear Dryness Nourish Ying Decoction)**
Anemarrhena (Zhi Mu), Trichosanthes Root (Gua Lou Gen), Angelica (Dang Gui), White Peony (Bai Shao Yao), Rehmannia (Sheng Di Huang), Tangerine Peel (Chen Pi), Licorice (Gan Cao), Juncus (Deng Xin).
Eight ingredients. Decoct in water, take warm.
If exterior residual heat persists, use Chai Hu Yang Ying Tang (Xiao Chai Hu Tang minus Pinellia/Ginseng, plus Tangerine Peel, Angelica, Peony, Magnolia Bark, Rehmannia, Rhubarb, Immature Bitter Orange, Ginger).
If phlegm-fluid clouds chest/diaphragm, use Gua Bei Yang Ying Tang.
**Gua Bei Yang Ying Tang (Trichosanthes & Fritillaria Nourish Ying Decoction)**
Trichosanthes Root (Gua Lou Gen), Fritillaria (Bei Mu), Trichosanthes Seed (Gua Lou Ren), Perilla Seed (Su Zi), Tangerine Peel (Ju Hong), White Peony (Bai Shao Yao), Angelica (Dang Gui), Anemarrhena (Zhi Mu), Ginger (Sheng Jiang).
Nine ingredients. Decoct in water, take warm.
Tongue coating: White indicates Mo Yuan pathogen; Yellow indicates Stomach. Old coating turns dark brown. White coating: do not purge. Yellow: purge. Black: urgent purge. Post-purge non-shedding coating, tongue prickles/cracks, short/stiff/curled tongue, white sand-like coating, hard black coating all require purging. White slippery coating indicates Mo Yuan pathogen. If other purgation signs exist, use Da Yuan Yin plus Rhubarb. Profuse sweat, surging-large pulse, thirst: Bai Hu Tang, do not purge. Only if red eyes, dry throat, fiery breath, yellow-red painful urination, restlessness, deep-rapid pulse is purging unquestionable. Epigastric pain, abdominal fullness, headache resolve immediately with purging. Early stage: do not purge. Blood depletion causes false dryness; use guiding methods.
Comparison of Cold Damage and Epidemic Disease: Cold Damage has感冒 (wind-cold invasion) cause: aversion to wind/cold, headache/body ache, fever with persistent aversion to cold, floating-tight pulse without sweat (Cold Damage); floating-slow pulse with sweat (Wind Strike). Epidemic onset lacks invasion cause; sudden chills, then fever without aversion to cold. Triggered by hunger/fullness, labor, or emotion, but mostly spontaneous. Cold Damage resolves with one sweat; Epidemic sweating fails. Cold Damage is not contagious; Epidemic is. Cold Damage enters hair follicles; Epidemic enters mouth/nose. Cold Damage causes immediate illness; Epidemic causes delayed illness. Cold Damage sweating comes first; Epidemic sweating comes last (after internal dissolution, spontaneous/night/battle sweat). Cold Damage does not cause macules; Epidemic does. Cold Damage transmits via meridians; Epidemic originates internally, overflowing into meridians (meridians don't transmit themselves). Cold Damage is acute; Epidemic lingers/worsens gradually or suddenly. Cold Damage starts with releasing exterior; Epidemic starts with venting/draining. Both transmit to Stomach, converging to use Cheng Qi Tang to guide pathogen out. Thus, they start differently but end similarly. Cold Damage pathogen enters from outside, no root, advances only, so purging cures. Epidemic hides in Mo Yuan, rooted deeply, interacting with Ying/Wei, damaging them ("dissolving"). Without dissolution, no transmission; without transmission, no exit; without exit, no cure. Why doesn't post-epidemic purging always cure? Because pathogens often transmit simultaneously exterior/interior. Half stays in muscles, half in Stomach. Stomach blockage prevents exterior Qi flow, trapping muscle pathogen. Post-purge interior flow smooths exterior Qi, allowing trapped muscle pathogen to reach surface as macules/sweat. Cold Damage purging lacks this mechanism. Though ending similarly, processes differ.
Yang patterns mimicking Yin occur in both Cold Damage and Plague. Yin patterns mimicking Yang occur in true Cold Damage but never in Warm Epidemic. Distinguish them. Yang mimicking Yin: exterior cold but interior heat, urine red/astringent. Yin mimicking Yang: Floating Yang pattern, upper heat/lower cold, urine clear/white. Urine color is the definitive key.
Four Damages (Si Sun) are incurable: excessive labor/desire, post-severe/prolonged illness, Qi/Blood deficiency, Yin/Yang exhaustion, Zheng Qi deficit leading to pathogen sinking. Epidemic presentation may be mild: headache, fever, sweat, normal appetite, walking ability mask the disease. Pulse is neither floating nor deep but rapid. Patients seek blame elsewhere, complaining falsely. Physicians failing to discern right/wrong quote Dong Yuan...