出张石顽《伤寒绪论》，中间略据鄙见补注。
舌苔之名，始于长沙，以其邪气结里，如有所怀，故谓之胎。（一谓之苔，如地之生苔者。）伤寒邪在
表，则苔不生。邪热传里，则苔渐生，自白而黄，黄而黑，黑甚则燥裂矣。要以滑润而白者为表邪，灰黑湿
润无苔为阴寒，（此即舌质之变色也。）灰黑薄滑为夹冷食，皆不可用寒凉攻下之剂。然中暑夹血，多
有中心黑润者，又不可拘此说。若黄黑灰色而干燥纹裂者为热极，万无虚寒夹血之理。（亦有因极热忽地饮冷
而胃口之血瘀结，见黑苔者。）惟屡经汗下，舌虽干而有微薄苔，却无燥裂芒刺，此为津液耗亡，不可误认
实热而攻之，必致不救。《金镜》三十六治法，举世宗之。又《观舌心法》一百三十八图，条分缕
析，辨证最详。其间论红为瘟热，紫为酒毒，霉酱为夹食，蓝为肝脏纯色，迥出前人未备，所嫌舍本逐末，未
免繁紊无纲领。因括其捷要，辨论于下∶
如白苔者，邪伤气分，肺主气而色白，又主皮毛，故凡白苔，犹带表证；仲景以为胸中有寒，止宜和解，
禁用攻下，攻下必致结痞，变证不测。若温病、热病，一发便壮热，昏愦燥渴，舌正赤（此即舌质）而有白
滑苔，即当用白虎汤汗之。（白虎汤虽可生汗，初起总宜略加表药。）时疫初起，舌上白苔如积粉者，达原饮
解之。若伤寒邪入胃腑，则白苔中黄；邪传少阴，则白中变黑。若纯色为一经证，边与中间两色俱传经证。若
从根至尖直分两路者，是合病与夹阴舌也。合病则白中兼两路黄，夹阴则白中兼两路黑润及灰色也。从
根至尖横分两三截苔色者，是并病舌也。（合病并病，分别含混。合病者，一邪而伤两经也，或虽
由此经传彼经，而仍是寒邪，谓两经合病于一邪也。并病者，此经寒邪蕴为彼经热病，或一经而有寒热之两
病，谓两邪并病于一身也。舌苔之直分横截，与此浑不相涉。直分二三路者，以表里分也。中间为里，两边为
表，左为肝胆，右为脾胃。横分两三截者，以三焦分也。尖为上焦，中为中焦，根为下焦，视其
色以决其寒热虚实也。）故尖白根黄，尖白根黑，及半边苔滑者，虽证类不同，皆属半表半里。白苔多而滑、
黄黑苔少者，表证多也，尚宜和解。黄黑苔多而白苔少，或生芒刺黑点干燥者，里证多也，必下无疑。虽
中心黄黑，而滑润边白者，此为表证未尽。（所谓表证未尽，即风寒尚未全化热也。鄙见即化热，仍是表
邪，与真正里证，总是不同。）伤寒则大柴胡两解之，温热时疫则凉膈散或白虎合承气攻下之。又伤寒坏病，
虽白而浓，甚燥裂者，此为邪耗津液，宜小柴胡稍加芒硝微利之。纯白滑苔，为胃虚寒饮结聚膈上之候，每
于十三四日过经致变，不可泛视也。一种白浓苔，如煮熟色到底不变者，必里挟寒物留滞不
散，致脉伏不出，乃心脾气绝，肺气受伤也，慎不可下。（寒滞不化，可用温下。）宜枳实理中汤，热甚，合
小陷胸下之。至于能食自利而白苔滑者，为脏结难治也。黄连汤、连理汤、备
急丸选用，间有得生者。
黄苔者，阳明腑实也。黄湿而滑者，为热未盛，结当未定，不可便攻，攻之必致初硬后溏也。冬时宜
确守此例，俟结定乃攻，不得已，大柴胡微利之。若在夏月，一见黄苔，便宜攻下。以夏月伏阴在内，多有下
证最急而苔不燥者，不可泥也。若黄而燥者，为热已盛，峻下无疑。黄而生芒刺黑点者，为热势极。黄而瓣
裂者，为胃液干，下证尤急也。诸黄苔皆属胃热，分缓急轻重下之。有种根黄而硬，尖白而中不甚
干，亦不滑，短缩不能伸出，谵妄烦乱者，（与前条半表半里证不同。）此痰挟宿食占据中宫也，大承气加
生姜半夏主之。有舌色青紫（此即舌质。）而苔却黄浓，甚则纹裂，但觉口燥，舌仍不干者，此阴
证夹食也。（青紫是有瘀血，非阴证也，是湿邪蕴积，深陷于血分之象。）脉
或沉细而伏，或虚大而涩，按其心下或脐旁硬痛，（结痰与瘀血相挟，多有此脉象证候。）
而时失气者，（若常失气，非有宿食燥屎，即当为气脱矣。）急宜大承气，另煎生附子佐大黄下之。若脉虚大
者，黄龙汤主之，热极烦躁者，更加生地、麦冬，夏月尤宜。若冬时阴证夹食，而舌上苔黄不燥者，宜用附
子理中合小承气下之。大抵舌有积苔，虽见阴象，亦是虚中有实，急当攻下无疑，但下法与寻常不同耳。又
中宫有痰饮水血者，舌多不燥，不可因其不燥，而延缓时日致误也。凡温病热病稍见黄白苔，无论燥润，即宜
凉膈双解。时行疫疠稍见白苔，即宜白虎、达原。若见黄黑，无论干湿，大承调胃，急夺无疑。
黑苔者，少阴肾色也。（血分瘀浊之极也。燥硬而隐隐见紫者，是
因热灼，以致血败。柔润而隐隐见淡者，水饮结而气不流行，以致血瘀也。）若五六日后，热传少阴，火
乘水位，亢极之火，不为水衰，反兼水化，（五行空谈，陋习也。此只是热邪深入，阴液全干，血瘀气浊，发
见枯滞之死色也。）如火过炭黑是也。始因表证失汗，（所以瘀也。）致邪入少阴，下之即愈。然有屡下，
热不减，苔不退者，此必宿食留滞于中宫也，宜黄龙汤加炮姜、川连。有误用汗下太过，津
液枯竭，（所以瘀也。）而苔燥黑者，此为坏病，须量人虚实为治。虚者其苔必薄而润，生脉散合附子理中；
实者其苔必浓而燥，生脉合黄连解毒；（解毒即三黄汤。）一则阴虚阳亢，一则阳虚阴
亢，不可不审。热势盛剧，则黑苔上生芒刺，及燥裂分隔瓣者，须用青布蘸薄荷汤拭润，更以姜片刮去芒刺，
撅起隔瓣，看刺下瓣底，（即舌质也。）色红可治，急下之；若俱黑，不治矣。又黑苔腐烂者，心肾俱绝；
舌黑而卷缩者，肝绝；皆不可治。舌黑及灰或黄，而发 生虫腐烂，虽为湿热，亦属
肝伤，俱为危候。又中间一路润黑燥苔，质润而苔燥也。两边
或黄或白者，两感舌也。（此或夙有蓄血，内正虚，外邪实，非两感也。篇中说两感皆未合。）
边黄则调胃承气，边白则大柴胡下之。若中间一路黑滑薄苔，两边白滑，此表里俱虚，胃中虽有留结，急
宜附子汤温之。凡黑苔多凶，（心气为瘀血所阻，邪气内溃甚速。）黑而干燥或芒刺瓣裂，皆为实热，急宜
下夺。黑薄湿润，或兼白滑者，皆为阴寒，急当温经也。一种中黑而枯，或略有微刺，色虽黑而中无积苔，舌
形枯瘦，而不甚赤，（此即舌质。）其证烦渴耳聋，身热不止，大便五六日或十余日不行，腹不硬
满，按之不痛，神识不昏，昼夜不得睡，稍睡或呢喃一二句，或带笑，或叹息，此为津枯血燥之候，急宜
炙甘草汤，或生料六味丸，换生地，合生脉散，加桂，滋其化源，庶或可生。误与承气必死，误与四逆亦死。
凡舌苔或半黄半黑，或半黄半白，或中燥边滑，或尖干根润，皆为传并之邪，寒热不和之候。大抵尖黑稍轻，
根黑至重，黄黑宜大承气，兼白者宜凉膈散，分缓急下之。若全黑，为死现舌，不治。（心血全瘀，）夏
月热病，邪火时火，内外燔灼，苔黑易生，犹可攻治。冬月伤寒，舌苔全黑，决难救也。（此乃指黑而润者，
是血因寒而瘀，夏热瘀易行，冬寒瘀难行也，若热瘀，即冬夏皆凶。）然中暑误认外感，而加
温复，多致中黑，边极红而润，脉必虚大，急用白虎汤清之，虚者加人参、竹叶。如更误认阴寒，而与热药，
必致烦躁不救也。夏月中暑，多有黑舌，黑而中干者，白虎无疑。黑而滑润，或边白者，必夹寒食。（前以
此为两感，为表里俱虚，此以为夹寒食，当以此文为得之。然尚遗却蓄血一证。蓄血有寒有热，亦辨于苔之
润燥也。夹痰者，多见灰色之苔，总因邪气关及血分致此。）古法用大顺散，然不若理中合小陷胸最当。若直
中少阴真寒，始病不发热，舌心便黑色，（如此必昏厥矣。）非由黄白变化，其苔虽黑而滑，舌亦
瘦小，此真脏寒，必厥冷，自利呕吐，脉沉迟，四逆附子辈急温
之，稍缓则不可救。
灰黑舌者，足三阴互病，如以青黄和入黑中，则为灰色也。（痰水主于脉中，致血微停瘀也。）然有传
经直中之殊，盖传经热邪，始自白苔而黄，黄而灰黑，或生芒刺黑点，纹裂干燥，不拘在根在尖，俱宜攻下
泄热，有淡灰色，中起深黑重晕者，（此病久寒热互结，或夙有痰饮蓄血，又新加以停滞也。若因内传一次，
即见一重也，于理难通，或者邪气化寒、化热、化燥、化湿，转变一次，即增一重，亦或伤冷、伤热、伤食、
伤饮，多伤一次，即增一重也。）乃温病热毒。急用凉膈双解治之。热毒内传一次，见晕一重，传二、三次，
见二、三重也。若见三重者，不治。若直中三阴，始病无燥热，便见灰色，舌润无苔，更不变别色者，此
必内夹寒食，及冷痰水饮，或蓄血如狂等证，当随证治之。又有感冒夹食，屡经汗下消导，二便已通，而舌
上灰黑未退或湿润，或虽不湿，亦不干燥者，不可因其湿，误认为寒，妄投姜附。亦不可因其不润，误与
硝黄。此因汗下过伤津液，虚火上炎所致，其脉必虚微少力，治宜救阴为急，虽无心悸脉代，当
用炙甘草汤主之。内有生地、阿胶、麻仁、麦冬之甘润，可以滋阴润燥。盖阳邪亢盛，则
用硝黄以救阴，阴血枯涸，则宜生地以滋阴，可不辨乎。
红色者，心之正色也。若红极为温热之毒，蕴于心胃，及瘟疫热毒内盛也。若湿者，不可便下，解
毒汤或白虎。红中有白苔者，更感非时之寒也，桂枝白虎汤。红中夹两路灰色苔者，温热而夹寒食也，凉膈
散加消导药一、二味。红中有黑苔者，热毒入少阴也，大承气合白虎汤。红极有黄黑芒刺
者，热毒入腑也，调胃承气汤。红极有紫红斑，及遍身发斑者，阳毒入心也，人参白虎汤加犀角、黄连。红极
而纹裂者，燥热入肝也，大承气加柴胡、白芍，甚则加芩、连。坑烂者，
湿热入脾也，小承气加芩、连、半夏。白 者，火气燔灼也，（浮浅不入血脉，止起白 。）三黄石膏去麻
黄。紫疮者，火气郁伏也，解毒汤。红星者，（即红珠鼓起也。）心包火炎也，凉膈散。一种柔
嫩如新生，望之似润，而燥涸殆甚者，为妄行汗下，津液竭
也，多不治。急宜生脉散和人参三白汤主之。舌痿不能转动者，肝绝，舌忽瘦而长，心绝也。
紫色者，酒后伤寒也。世俗庸愚，往往受寒，不服汤药，用姜、葱、酒发汗，汗未当而酒毒藏于心包，
多有此证。（有化为湿温者，有化为酒毒者，推其所以，皆由寒气束于大表，酒力不能外行，
而内积于胃与包络也。）若纯紫，或中间略带白苔而润者，宜葛根汤加石膏。若紫中有红斑，或紫而干黄，
紫而短缩，俱宜凉膈散下之。若全紫而干，如煮熟肝者，死肝色也，其证必厥冷，脉必沉滑。（血脉瘀阻，阳
郁不达。）此阳极似阴也。急宜当归四逆汤加酒大黄下之。（再加桃仁。）然多不救。（当归四逆尚嫌近补，
大黄又嫌泄气。此证宜宣散，而化血通脉，使血开气达。）大抵深紫而赤者，是阳热酒毒，宜用苦寒解毒。
（宜重化瘀。）若淡紫而带青滑者，是则中肾肝阴证，急宜吴茱萸汤、四逆汤温之。（宜兼化瘀。）然
亦有中心生薄青紫苔，或略带灰黑而不燥不湿下证复急者，此热邪伤于血分也，犀角地黄汤加酒大黄微利之。
（红紫二舌，均指舌质言之，固无红苔，亦断无紫苔，其有见紫苔者，必舌面已腐，或微黑
苔，与赤红相映而然也。）
霉酱色苔舌者，乃夹食伤寒也。食填太阴，郁遏不得发越，久之 而成酱色也。其证腹满时痛者，桂枝
加枳、朴、橘、半，痛甚加大黄。因冷食不消，加炮姜、浓朴，甚则调胃承气加炮姜下之。如胃气绝，脉结
代，唇吊齿燥，下利者死。（按∶此即沉香色也。总是血瘀气浊所致。湿热夹痰，亦常有之，不仅夹食也。）
蓝苔色舌者，肝脏纯色也。（含糊。）伤寒日久，屡经汗下，失于调理，致胃气伤极，心火无气，脾
土无根据，则肺金不生；肝木无制，侮于脾土，故苔色如靛；或兼身生蓝斑，乃心脾肺三脏气绝于内也，必死。
如微蓝色，而不甚深，或略见蓝纹者，为木受金伤，脏气未绝，脉不沉涩，而微弦者，可治。
（此语极有道理，惜欠发明。沉涩者，正气不至，脉形断续不匀也。微弦者，气能至而血阻之，故脉形绷
急也。）小柴胡加肉桂、炮姜主之。（按∶常见痫厥，及胃气久痛者，舌体全蓝，此亦瘀血在胃，肝气不舒
也。故青黑蓝绛，皆谓之浊，皆涉血分，须辨寒、热，燥、湿及痰血、宿食、燥屎、症块而治之，
总以松动血分为主。）舌之证类虽繁，不外八种苔色，撮其大要，亦辨证之一助也。（张石顽《伤寒绪论》。）
出自张石顽的《伤寒绪论》，其中略加了我个人的见解作为补注。
“舌苔”这一名称，始于长沙（指张仲景），因为邪气结聚在体内，如同有所孕育，所以称为胎。（另一种说法称为苔，就像地面上生长青苔一样。）伤寒病邪在体表时，舌上不生苔。邪热传入体内后，舌苔逐渐生成，由白色转为黄色，由黄色转为黑色，黑色严重时则出现干燥裂纹。一般来说，滑润而白色的舌苔属于表邪；灰黑色、湿润且无苔的是阴寒证（这实际上是舌质的变色）；灰黑色且薄而滑润的是夹杂冷食所致，这些情况都不可使用寒凉攻下的方剂。然而，中暑兼有瘀血的患者，舌中心常呈黑润色，又不宜拘泥于上述说法。如果是黄、黑、灰色且干燥、有裂纹的舌苔，则是热极的表现，绝无虚寒夹瘀血的道理。（也有因极度发热时突然饮用冷饮，导致胃脘部血液瘀结，而出现黑苔的情况。）只有经过多次发汗和攻下治疗后，舌面虽然干燥但有微薄之苔，却没有燥裂和芒刺，这是津液耗竭亡失的表现，不可误认为是实热证而进行攻下治疗，否则必然导致死亡。《金镜录》中的三十六治法，被世人所尊崇。还有《观舌心法》中的一百三十八幅图，条理清晰，辨证最为详细。其中论述红色为瘟热，紫色为酒毒，霉酱色为夹食，蓝色为肝脏的本色，这些都超出了前人的记载，可惜舍本逐末，未免繁杂混乱而无纲领。因此我概括其要点，在下文进行辨论：
如果是白苔，说明邪气损伤了气分。肺主气，其色白，又主皮毛，所以凡是白苔，都带有表证的特征。张仲景认为胸中有寒，只宜和解，禁用攻下，若强行攻下必然导致痞满结聚，变证莫测。如果是温病、热病，一发病就出现高热、神志昏沉、烦躁口渴，舌质正红（这就是舌质）而表面有白滑苔，就应当使用白虎汤来发汗。（白虎汤虽然能生津发汗，但初起时总宜略微加入解表药。）时疫初起，舌上白苔如积粉状，用达原饮来解除。如果伤寒邪气传入胃腑，则白苔中泛黄；邪气传入少阴经，则白苔中变黑。如果舌苔颜色纯粹单一，是一经病的证候；边缘与中间两种颜色同时出现，是传经的病证。如果从舌根到舌尖直分为两路，这是合病与夹阴舌。合病则白苔中兼有两路黄色；夹阴则白苔中兼有两路黑润及灰色。如果从舌根到舌尖横分为两三截不同颜色的苔，这是并病舌。（合病与并病的概念区分含混不清。所谓合病，是一个邪气同时伤害两条经脉；或者虽然由此经传到彼经，但仍然是寒邪，称为两经合病于一邪。所谓并病，是此经的寒邪郁滞转化为彼经的热病，或者一经之中同时存在寒热两种病证，称为两邪并病于一身。舌苔的直分与横截，与此概念毫无关系。直分二三路，是以表里来划分的。中间为里，两边为表，左边对应肝胆，右边对应脾胃。横分两三截，是以三焦来划分的。舌尖为上焦，舌中为中焦，舌根为下焦，观察其颜色来判断寒热虚实。）所以，舌尖白而舌根黄，舌尖白而舌根黑，以及半边苔滑润的，虽然症状类别不同，都属于半表半里证。白苔多且滑润、黄黑苔少的，表证较多，仍宜和解。黄黑苔多而白苔少，或生有芒刺、黑点且干燥的，里证较多，必定需要攻下，没有疑问。即使中心黄黑，但边缘滑润且白的，这是表证尚未完全解除。（所谓表证未尽，即风寒尚未完全化热。我的观点是，即使化热，仍属表邪，与真正的里证总是不同的。）伤寒则用大柴胡汤表里双解；温热时疫则用凉膈散或白虎汤合承气汤攻下。另外，伤寒坏病，舌苔虽白而浓厚，甚至燥裂的，这是邪气耗伤津液，宜用小柴胡汤稍加芒硝轻微通利。纯白滑苔，是胃虚寒饮结聚在膈上的征象，常在十三四天过后经气传变时发生变故，不可忽视。还有一种白浓苔，像煮熟的颜色到底不变化的，必然是里部挟带寒物留滞不散，导致脉伏不出，这是心脾气绝、肺气受伤的表现，千万不可攻下。（寒滞不化，可用温下法。）宜用枳实理中汤，如果热势甚重，合用小陷胸汤攻下。至于能进食且自利（腹泻）而舌苔白滑的，是脏结证，难以治疗。可选用黄连汤、连理汤、备急丸，偶尔有获救的。
黄苔，属于阳明腑实证。黄而湿滑的，说明热势未盛，结聚尚未确定，不可立即攻下，攻下必然导致初硬后溏。冬季应当严格遵循此例，等待结聚确定后再攻下，不得已时，用大柴胡汤轻微通利。如果在夏季，一见黄苔，就适宜攻下。因为夏季体内潜伏阴气，多有最急需攻下的证候而舌苔不干燥的情况，不可拘泥。如果黄而干燥的，说明热势已盛，峻猛攻下无疑。黄而生有芒刺黑点的，说明热势极盛。黄而有瓣状裂纹的，说明胃液干枯，攻下的证候尤为紧急。各种黄苔都属于胃热，需根据缓急轻重进行攻下。有一种舌根黄而硬，舌尖白而中间不甚干燥，也不滑润，舌体短缩不能伸出，伴有谵语妄言、烦躁混乱的，（这与前面的半表半里证不同。）这是痰浊挟带宿食占据中焦，用大承气汤加生姜、半夏主治。有舌色青紫（这就是舌质）而舌苔却黄浓，甚至出现裂纹，只感觉口燥，但舌面仍然不干润的，这是阴证夹食。（青紫是有瘀血，并非单纯的阴证，而是湿邪蕴积，深陷于血分的表现。）脉象或沉细而伏，或虚大而涩，按压心下或脐旁感到硬痛，（结痰与瘀血相挟，多有这种脉象证候。）并且时常放屁的，（如果经常放屁，不是有宿食燥屎，就是气脱了。）急需大承气汤，另煎生附子佐助大黄攻下。如果脉象虚大的，用黄龙汤主治，热极烦躁的，再加生地、麦冬，夏季尤其适宜。如果冬季阴证夹食，而舌上苔黄不干燥的，宜用附子理中汤合小承气汤攻下。大抵舌上有积苔，即使见到阴象，也是虚中有实，急需攻下无疑，只是攻下的方法与寻常不同罢了。另外，中焦有痰饮、水气、瘀血的，舌苔大多不干燥，不可因为舌苔不干燥，就拖延时日以致误事。凡是温病热病稍微见到黄白苔，无论干燥还是湿润，就宜用凉膈散双解。时行疫病稍微见到白苔，就宜用白虎汤、达原饮。如果见到黄黑苔，无论干湿，大承气汤、调胃承气汤急夺邪气无疑。
黑苔，是少阴肾的颜色。（这是血分瘀浊到了极点。干燥坚硬且隐隐见紫色的，是因为热邪灼烧，导致血液败坏。柔润且隐隐见淡色的，是水饮结聚而气机不流通，导致血瘀。）如果五六日后，热邪传入少阴，火邪乘袭水位，亢极的火邪，不为水衰所制，反而兼有水化，（五行空谈，是陋习。这只是热邪深入，阴液全干，血瘀气浊，呈现出枯滞的死色。）就像火过后的木炭那样。起初因为表证失于发汗，（所以导致瘀血。）致使邪气入少阴，攻下即可痊愈。但是有屡次攻下，热势不减，舌苔不退的，这必然是宿食留滞在中焦，宜用黄龙汤加炮姜、川连。有误用发汗和攻下太过，导致津液枯竭，（所以导致瘀血。）而舌苔燥黑的，这是坏病，必须衡量病人的虚实进行治疗。虚证的舌苔必薄而润，用生脉散合附子理中汤；实证的舌苔必浓而燥，用生脉散合黄连解毒汤；（解毒汤即三黄汤。）一个是阴虚阳亢，一个是阳虚阴亢，不可不仔细审察。热势盛剧，则在黑苔上生芒刺，及干燥裂开分隔成瓣的，须用青布蘸薄荷汤擦拭润湿，再用姜片刮去芒刺，撬起隔瓣，看刺下瓣底（即舌质）的颜色，如果色红可治，急下之；如果全部发黑，则无法治疗。另外黑苔腐烂的，心肾俱绝；舌黑而卷缩的，肝绝；都无法治疗。舌黑及灰或黄，而生虫腐烂的，虽然是湿热，也属于肝伤，都是危重证候。又一种中间一路润黑、周围干燥的舌苔，是舌质润而舌苔燥。两边或黄或白的，是两感舌。（这可能是素来有蓄血，内里正气虚，外邪实，并非两感证。篇中说两感皆未符合。）边黄则用调胃承气汤，边白则用大柴胡汤攻下。如果中间一路黑滑薄苔，两边白滑，这是表里俱虚，胃中虽有留结，急需附子汤温补。凡黑苔多主凶险，（心气被瘀血阻滞，邪气内溃迅速。）黑而干燥或有芒刺瓣裂的，皆为实热，急需攻下夺邪。黑而薄湿润，或兼白滑的，皆为阴寒，急需温经。一种舌中黑而枯，或略有微刺，颜色虽黑但中间无积苔，舌形枯瘦，而不甚赤红的，（这就是舌质。）其症状为烦渴耳聋，身热不止，大便五六日或十余日不行，腹部不硬满，按压不痛，神识不昏迷，昼夜不得睡眠，稍睡或呢喃一二句，或带笑，或叹息，这是津枯血燥的证候，急需炙甘草汤，或生料六味丸换生地，合生脉散，加桂枝，滋养化源，或许可以存活。误用承气汤必死，误用四逆汤亦死。
凡是舌苔或半黄半黑，或半黄半白，或中燥边滑，或尖干根润，都是传经并病之邪，寒热不和的证候。大抵舌尖黑较轻，舌根黑至重，黄黑者宜大承气汤，兼白者宜凉膈散，根据缓急攻下。如果全黑，是死现舌，无法治疗。（心血完全瘀阻。）夏季热病，邪火与时火内外燔灼，舌苔黑易生，还可以攻治。冬季伤寒，舌苔全黑，决难救活。（这里指的是黑而润的，是血因寒而瘀，夏季热瘀易行，冬季寒瘀难行，如果是热瘀，则冬夏皆凶。）然而中暑误认作外感，而加上温复疗法，多导致舌中黑，边缘极红而润，脉必虚大，急需白虎汤清解，虚者加人参、竹叶。如果再误认作阴寒，而给予热药，必然导致烦躁无法救治。夏季中暑，多有黑舌，黑而中间的干燥的，白虎汤无疑。黑而滑润，或边缘白的，必然夹寒食。（以前将此视为两感，视为表里俱虚，此处视为夹寒食，以此文为准。然而还遗漏了蓄血一证。蓄血有寒有热，也要辨别舌苔的润燥。夹痰者，多见灰色之苔，总因邪气波及血分导致此象。）古法用大顺散，然而不如理中汤合小陷胸汤恰当。如果直中少阴真寒，初起不发热，舌心便呈黑色，（如此必昏厥矣。）不是由黄白变化而来，其苔虽黑而滑，舌体也瘦小，这是真脏寒，必然四肢厥冷，自利呕吐，脉沉迟，四逆汤、附子类方剂急需温补，稍迟缓则不可救。
灰黑舌，是足三阴经互相患病，如将青黄混合入黑中，则为灰色。（痰水主要在于脉中，导致血液轻微停瘀。）然而有传经直中之别，大概传经的热邪，开始是白苔转黄，黄转灰黑，或生芒刺黑点，纹裂干燥，不管在根还是在尖，都宜攻下泄热。有淡灰色，中间起深黑重晕的，（这是病久寒热互结，或素来有痰饮蓄血，又新加以停滞。如果因内传一次，就见一重，于理难通，或许是邪气化寒、化热、化燥、化湿，转变一次，即增一重，或者是伤冷、伤热、伤食、伤饮，多伤一次，即增一重。）这是温病热毒。急需凉膈散双解治疗。热毒内传一次，见晕一重，传二、三次，见二、三重。如果见三重，则无法治疗。如果直中三阴，初起无燥热，便见灰色，舌润无苔，更不变其他颜色，这必然是内夹寒食，及冷痰水饮，或蓄血如狂等证，当随证治疗。又有感冒夹食，屡经发汗、攻下、消导，二便已通，而舌上灰黑未退或湿润，或虽不湿，也不干燥的，不可因其湿润，误认为寒，妄投姜附。也不可因其不润，误用硝黄。这是因为汗下过度损伤津液，虚火上炎所致，其脉必虚微少力，治疗宜救阴为急，虽然没有心悸脉代，也当用炙甘草汤主治。内有生地、阿胶、麻仁、麦冬的甘润，可以滋阴润燥。大概阳邪亢盛，则用硝黄以救阴，阴血枯涸，则宜生地以滋阴，可不分辨吗？
红色，是心的正色。如果红至极点是温热之毒，蕴结于心胃，及瘟疫热毒内盛。如果湿润的，不可立即攻下，用解毒汤或白虎汤。红中有白苔的，是更感非时之寒，用桂枝白虎汤。红中夹两路灰色苔的，是温热而夹寒食，用凉膈散加消导药一、二味。红中有黑苔的，是热毒入少阴，用大承气汤合白虎汤。红至极点有黄黑芒刺的，是热毒入腑，用调胃承气汤。红至极点有紫红斑，及遍身发斑的，是阳毒入心，用人参白虎汤加犀角、黄连。红至极点而纹裂的，是燥热入肝，用大承气汤加柴胡、白芍，甚则加黄芩、黄连。坑烂的，是湿热入脾，用小承气汤加黄芩、黄连、半夏。白色的，是火气燔灼，（浮浅不入血脉，只起白斑。）用三黄石膏汤去麻黄。紫疮的，是火气郁伏，用解毒汤。红星的，（即红珠鼓起。）是心包火炎，用凉膈散。一种柔嫩如新生，望之似润，而燥涸极其严重的，是妄行汗下，津液竭尽，大多无法治疗。急需生脉散和人参三白汤主治。舌痿不能转动的是肝绝，舌忽然瘦而长的是心绝。
紫色，是酒后伤寒。世俗庸医愚夫，往往受寒后不服汤药，用姜、葱、酒发汗，汗未出透而酒毒藏于心包，多有此证。（有的化为湿温，有的化为酒毒，推究其原因，都是因为寒气束于体表，酒力不能外行，而内积于胃与心包络。）如果纯紫，或中间略带白苔而润的，宜葛根汤加石膏。如果紫中有红斑，或紫而干黄，紫而短缩的，都宜凉膈散攻下。如果全紫而干，像煮熟的肝脏，是死肝色，其症状必然厥冷，脉必沉滑。（血脉瘀阻，阳气郁滞不达。）这是阳极似阴。急需当归四逆汤加酒大黄攻下。（再加桃仁。）然而大多无法救治。（当归四逆汤尚嫌偏补，大黄又嫌泄气。此证宜宣散，而化瘀通脉，使血开气达。）大抵深紫而赤的，是阳热酒毒，宜用苦寒解毒。（宜重化瘀。）如果淡紫而带青滑的，则是中肾肝阴证，急需吴茱萸汤、四逆汤温补。（宜兼化瘀。）然而也有中心生薄青紫苔，或略带灰黑而不燥不湿，攻下证候又急的，这是热邪伤于血分，用犀角地黄汤加酒大黄轻微通利。（红紫二舌，均指舌质而言，本来就没有红苔，也断无紫苔，那些见到紫苔的，必然是舌面已腐，或微黑苔，与赤红相映才这样。）
霉酱色苔舌，是夹食伤寒。食物填塞太阴，郁遏不得发散，久而久之而成酱色。其症状腹部胀满时痛的，用桂枝加枳壳、厚朴、橘皮、半夏，痛甚加大黄。因冷食不消，加炮姜、厚朴，甚则调胃承气汤加炮姜攻下。如果胃气绝，脉结代，唇吊齿燥，下利的，死。（按：这就是沉香色。总是血瘀气浊所致。湿热夹痰，也常有这种情况，不仅限于夹食。）
蓝苔色舌，是肝脏的本色。（含糊不清。）伤寒日久，屡经发汗攻下，失于调理，导致胃气伤极，心火无气，脾土无根据，则肺金不生；肝木无制，侮于脾土，所以苔色如靛蓝；或兼身生蓝斑，是心脾肺三脏气绝于内，必死。如果微蓝色，而不甚深，或略见蓝纹的，是木受金伤，脏气未绝，脉不沉涩，而微弦的，可治。（这话极有道理，可惜缺乏阐明。沉涩者，正气不至，脉形断续不匀。微弦者，气能至而血阻之，故脉形绷急。）用小柴胡汤加肉桂、炮姜主治。（按：常见痫厥，及胃气久痛者，舌体全蓝，这也是瘀血在胃，肝气不舒。所以青黑蓝绛，都称之为浊，都涉及血分，须辨别寒、热，燥、湿及痰血、宿食、燥屎、症块而治疗，总以松动血分为主。）舌的证类虽然繁多，不外乎八种苔色，撮取其大要，也是辨证的一个帮助。（张石顽《伤寒绪论》。）
From Zhang Shiwen's *Shanghan Xulun* (Treatise on the Sequel to Cold Damage), with slight annotations added based on my own views.
The term "tongue coating" (She Tai, tongue coating) originated from Changsha (referring to Zhang Zhongjing). Because pathogenic factors are knotted in the interior, as if something is gestating, it is called "tai" (fetus/germ). (Another term used is "tai", like moss growing on the ground.) When the pathogen of cold damage is at the exterior, no coating forms on the tongue. When pathogenic heat transmits to the interior, the coating gradually appears, turning from white to yellow, and from yellow to black; when black becomes severe, dryness and fissures appear. Generally, a slippery and white coating indicates exterior pathogenic factors; gray-black, moist, and without coating indicates yin-cold (this is actually a change in the color of the tongue body); gray-black, thin, and slippery indicates retention of cold food. In these cases, cold-cooling purgative formulas must not be used. However, in cases of summerheat combined with blood stasis, the center of the tongue is often black and moist, so one should not rigidly adhere to this rule. If the coating is yellow, black, or gray, dry, and fissured, it indicates extreme heat, and there is absolutely no possibility of deficiency-cold combined with blood stasis. (There are also cases where extreme heat followed by sudden ingestion of cold drinks causes blood stasis in the stomach region, resulting in a black coating.) Only after repeated sweating and purging, if the tongue is dry but has a very thin coating, without dryness, fissures, or prickles, does this indicate exhaustion of body fluids. It must not be mistaken for excess heat and treated with purgatives, otherwise death is inevitable. The thirty-six treatment methods in *Jingxian* (Golden Mirror) are revered by the world. Furthermore, the 138 diagrams in *Guan She Xinfa* (New Methods for Observing the Tongue) are detailed and well-organized in differentiation. Among them, red is discussed as epidemic heat, purple as alcohol toxin, moldy-soybean color as food retention, and blue as the pure color of the liver. These exceed previous records, but unfortunately, they lose sight of the root for the branches, becoming somewhat chaotic and lacking a guiding principle. Therefore, I have summarized their essentials and discuss them below:
If the coating is white, it indicates that the pathogen has injured the qi level. The lung governs qi, its color is white, and it governs the skin and hair. Therefore, any white coating carries characteristics of an exterior syndrome. Zhang Zhongjing believed that cold in the chest requires only harmonization and strictly prohibits purging; purging will inevitably lead to fullness and obstruction, with unpredictable complications. If it is warm disease or febrile disease, presenting immediately with high fever, stupor, restlessness, and thirst, with a red tongue body (this refers to the tongue body itself) covered by a white-slippery coating, Baizhu Tang (White Tiger Decoction) should be used to induce sweating. (Although Baizhu Tang can generate fluids and induce sweating, in the early stage, it is generally advisable to add a small amount of exterior-releasing herbs.) In the early stage of epidemic diseases, if the white coating on the tongue resembles accumulated powder, Dayuan Yin (Origin-Reaching Decoction) should be used to resolve it. If the pathogen of cold damage enters the stomach fu organ, the white coating turns yellow in the center; if the pathogen transmits to the Shaoyin channel, the white coating turns black. If the coating color is uniform, it is a syndrome of a single channel; if two colors appear simultaneously at the edges and center, it is a transmitting syndrome. If the tongue is divided straight into two paths from root to tip, it is a Hebing (Combined Disease) or Jia Yin (Clasping Yin) tongue. In Hebing, the white coating includes two paths of yellow; in Jia Yin, the white coating includes two paths of black-moist and gray coatings. If the tongue is divided horizontally into two or three sections of different colored coatings from root to tip, it is a Bingbing (Concurrent Disease) tongue. (The distinction between Hebing and Bingbing is ambiguous. Hebing refers to one pathogen injuring two channels simultaneously, or although transmitting from one channel to another, it remains cold pathogen, meaning two channels are combined under one pathogen. Bingbing refers to cold pathogen in one channel transforming into heat disease in another, or one channel having both cold and heat syndromes, meaning two pathogens concurrently affect the body. The straight division and horizontal segmentation of tongue coatings are unrelated to these concepts. Straight division into two or three paths divides by interior and exterior: the center is interior, the sides are exterior; the left corresponds to Liver/Gallbladder, the right to Spleen/Stomach. Horizontal division into two or three sections divides by Sanjiao: the tip is Upper Jiao, the middle is Middle Jiao, the root is Lower Jiao. Observe the color to determine cold, heat, deficiency, and excess.) Therefore, a white tip and yellow root, a white tip and black root, or a slippery half-tongue, although the symptoms differ, all belong to the Half-Exterior Half-Interior syndrome. More white coating and slippery, with less yellow/black coating, indicates more exterior syndrome, still suitable for harmonization. More yellow/black coating and less white coating, or presence of prickles, black spots, and dryness, indicates more interior syndrome, definitely requiring purging. Even if the center is yellow/black but the edges are slippery and white, this indicates the exterior syndrome is not fully resolved. (What is meant by "exterior syndrome not fully resolved" is that wind-cold has not completely transformed into heat. My view is that even if it transforms into heat, it still belongs to exterior pathogen, which is always different from true interior syndrome.) For cold damage, Dahuang Chaihu Tang (Major Rhabarber and Bupleurum Decoction) resolves both exterior and interior; for warm diseases and epidemics, Liangge San (Cooling the Chest Powder) or Baihu Tang combined with Chengqi Tang purges the interior. Additionally, in complicated cases of cold damage, if the coating is white but thick, even dry and fissured, this indicates the pathogen has consumed body fluids. Xiaochaihu Tang (Minor Bupleurum Decoction) with a little Mangxiao (Mirabilite) should be used for mild purgation. Pure white-slippery coating indicates deficiency-cold and fluid retention knotting above the diaphragm due to stomach deficiency. This often leads to changes after passing through the meridian cycle on the thirteenth or fourteenth day and should not be overlooked. Another type is a thick white coating that remains unchanged like cooked color throughout; this indicates retention of cold pathogenic substances in the interior that do not dissipate, leading to hidden pulse, indicating exhaustion of Heart and Spleen qi and injury to Lung qi. Purging must be strictly avoided. (For cold stagnation that does not transform, warm purging can be used.) Zhishi Lizhong Tang (Immature Bitter Orange and Spleen-Nourishing Decoction) is indicated; if heat is severe, combine with Xiaoxianxiong Tang (Minor Chest-Hamstring Decoction) to purge. As for those who can eat and have spontaneous diarrhea with white-slippery coating, this is Zangjie (Organ Knotting), which is difficult to treat. Huanglian Tang, Lianli Tang, or Beijij Wan may be selected, with occasional survival.
Yellow coating indicates Yangming Fu excess. Yellow, wet, and slippery indicates heat is not yet intense, and the knotting is not yet fixed; immediate purging should be avoided, as purging will lead to initial hardness followed by loose stools. In winter, this rule should be strictly observed, waiting until the knotting is fixed before purging; if unavoidable, use Dahuang Chaihu Tang for mild purgation. In summer, upon seeing a yellow coating, purging is appropriate. This is because summer involves latent yin inside the body, and there are many cases where purging is most urgent despite non-dry coating; one should not be dogmatic. If yellow and dry, heat is intense, and vigorous purging is indicated. Yellow with prickles and black spots indicates extreme heat intensity. Yellow with lobulated fissures indicates dryness of stomach fluids, making purging especially urgent. All yellow coatings belong to stomach heat; purging should be adjusted according to severity and urgency. There is a case where the root is yellow and hard, the tip is white, the middle is not very dry nor slippery, the tongue is short and cannot extend, accompanied by delirium and restlessness (different from the previous half-exterior half-interior syndrome). This is phlegm combined with retained food occupying the center. Dachengqi Tang (Major Order the Qi Decoction) with Shengjiang (Fresh Ginger) and Banxia (Pinellia) is indicated. There is a case where the tongue body is cyan-purple (this refers to the tongue body) but the coating is thick yellow, even fissured, feeling dry in the mouth but the tongue surface is not dry. This is yin syndrome combined with food retention. (Cyan-purple indicates blood stasis, not merely yin syndrome; it is a sign of damp-pathogen accumulation sinking deep into the blood level.) The pulse may be deep, fine, and hidden, or deficient, large, and choppy. Pressing the epigastrium or beside the navel reveals hardness and pain (phlegm knotting and blood stasis together often present with this pulse and symptom pattern), and frequent passage of gas. (Frequent passage of gas indicates either retained food/dry stool or qi collapse.) Urgently use Dachengqi Tang, decocting Sheng Fuzi (Raw Aconite) separately to assist Dahuang in purging. If the pulse is deficient and large, Huanglong Tang (Yellow Dragon Decoction) is indicated; for extreme heat and restlessness, add Shengdi (Rehmannia) and Maidong (Ophiopogon), especially suitable in summer. In winter, for yin syndrome combined with food retention with yellow non-dry coating, use Fuzi Lizhong Tang combined with Xiaochengqi Tang (Minor Order the Qi Decoction) to purge. Generally, if there is accumulated coating on the tongue, even if yin signs are seen, it is deficiency mixed with excess, requiring urgent purging, though the method differs from ordinary cases. Furthermore, if there is phlegm, fluid, water, or blood stasis in the center, the tongue coating is mostly not dry. Do not delay treatment because the coating is not dry. Whenever warm disease or febrile disease shows slight yellow-white coating, regardless of dryness or moisture, Liangge Shuangjie (Cooling the Chest Dual Resolution) is appropriate. For seasonal epidemics showing slight white coating, Baihu Tang and Dayuan Yin are appropriate. If yellow-black coating is seen, regardless of dryness or moisture, Dachengqi or Tiaowei Chengqi Tang should be used urgently to seize the pathogen.
Black coating is the color of Shaoyin Kidney. (This is extreme turbidity and stasis in the blood level. Dry and hard with faint purple indicates burning by heat causing blood deterioration. Soft and moist with faint pale color indicates water-fluid retention blocking qi circulation, causing blood stasis.) If after five or six days, heat transmits to Shaoyin, fire attacks the water position, the hyperactive fire, instead of being controlled by water deficiency, assumes water transformation (Five Elements theory is empty talk and a bad habit; this simply means heat pathogen has penetrated deeply, yin fluids are completely exhausted, blood is stasis and qi is turbid, presenting a withered and stagnant death color), like charcoal after fire. Initially due to failure to sweat for exterior syndrome (causing stasis), the pathogen enters Shaoyin; purging cures it. However, in cases of repeated purging where heat does not decrease and coating does not recede, this is due to retained food in the center. Huanglong Tang with Pao Jiang (Roasted Ginger) and Chuan Lian (Coptis) is indicated. If excessive sweating and purging were mistakenly used, leading to exhaustion of fluids (causing stasis) and dry black coating, this is a complicated disease. Treatment must be based on assessing deficiency and excess. Deficiency presents with thin, moist coating; Shengmai San combined with Fuzi Lizhong Tang is used. Excess presents with thick, dry coating; Shengmai San combined with Huanglian Jiedu Tang (Coptis Detoxification Decoction) is used. (Jiedu Tang is Sanhuang Tang.) One is yin deficiency with yang hyperactivity, the other is yang deficiency with yin hyperactivity; careful examination is required. If heat is extremely intense, prickles appear on the black coating, and it dries and separates into lobes. Use a blue cloth dipped in Bohe Tang (Mint Decoction) to wipe and moisten, then use ginger slices to scrape off prickles and lift the lobe edges to observe the base (the tongue body). If red, it is treatable; purge urgently. If entirely black, it is untreatable. Black coating rotting indicates exhaustion of Heart and Kidney; black tongue curling inward indicates exhaustion of Liver; both are untreatable. Black, gray, or yellow tongue with worm-like rotting, although due to damp-heat, also indicates Liver injury and is critical. Another type is a central moist black coating with dry surroundings, indicating moist tongue body but dry coating. Yellow or white on both sides indicates Lianggan (Dual Infection) tongue. (This might be pre-existing blood stasis, internal deficiency, external excess, not necessarily Lianggan. The text states Lianggan cases do not fit here.) Yellow edges suggest Tiaowei Chengqi Tang; white edges suggest Dahuang Chaihu Tang to purge. If the center has thin black-slippery coating and sides are white-slippery, this indicates both exterior and interior deficiency. Although there is retention in the stomach, Fuzi Tang should be used urgently to warm. Most black coatings are ominous (Heart qi blocked by blood stasis, pathogen溃 rapidly inside). Black, dry, or with prickles/fissures indicates excess heat, requiring urgent purging. Thin, moist black, or with white-slippery, indicates yin-cold, requiring urgent warming of meridians. A type with black, withered center, or slight prickles, black color but no accumulated coating in the center, withered and thin tongue shape, not very red (this is the tongue body), with symptoms of restlessness, thirst, deafness, continuous fever, constipation for 5-6 or 10+ days, abdomen not hard/full, painless on pressure, clear consciousness but unable to sleep day or night, muttering slightly when sleeping, smiling, or sighing, indicates exhaustion of fluids and dryness of blood. Jiugao Gancao Tang (Honey-Fried Licorice Decoction) or Shengli Liuwei Wan (Six-Ingredient Rehmannia Pill with Raw Rehmannia) combined with Shengmai San and Guizhi (Cinnamon Twig) to nourish the source of transformation is urgent. Mistaken use of Chengqi Tang leads to death; mistaken use of Sini Tang also leads to death.
Whenever the tongue coating is half-yellow half-black, half-yellow half-white, dry in center and slippery at edges, or dry at tip and moist at root, it indicates transmitting and concurrent pathogenic factors, and disharmony of cold and heat. Generally, black tip is slightly mild, black root is severe. Yellow-black requires Dachengqi Tang; if mixed with white, Liangge San is suitable. Purge according to urgency. If entirely black, it is a death-sign tongue, untreatable (complete blood stasis in Heart blood). In summer febrile diseases, with evil fire and seasonal fire burning internally and externally, black coating generates easily but can still be treated with purging. In winter cold damage, entirely black coating is difficult to save. (This refers to black and moist, where blood stasis is caused by cold; summer heat allows easier blood flow, winter cold makes blood stasis harder to move; if heat-stasis, both seasons are fatal.) However, if summerheat is mistaken for exterior sensation and treated with warming/recovering methods, the center often becomes black, edges very red and moist, pulse deficient and large. Baihu Tang should be used urgently to clear; add Renshen (Ginseng) and Zhuye (Bamboo Leaf) for deficiency. If further mistaken for yin-cold and given hot medicines, restlessness and death will result. Summer summerheat often presents with black tongue. Black with dry center indicates Baihu Tang is certain. Black with slippery/moist texture or white edges indicates cold-food retention. (Previously considered Lianggan or interior-exterior deficiency, here considered cold-food retention, which is more accurate. However, blood stasis was omitted. Blood stasis has cold and heat types, distinguished by coating moisture/dryness. Phlegm retention often shows gray coating, generally due to pathogen affecting blood level.) Ancient methods used Dashun San, but Lizhong Tang combined with Xiaoxianxiong Tang is more appropriate. If direct invasion of Shaoyin True Cold occurs, starting without fever, the tongue center is black (leading to coma/collapse), not changing from yellow/white. Coating is black but slippery, tongue is thin/small. This is True Organ Cold, with cold limbs, spontaneous diarrhea, vomiting, deep-slow pulse. Sini Tang and Fuzi-type formulas should be used urgently to warm; delay leads to untreatability.
Gray-black tongue indicates mutual disease of the three Foot-Yin channels. Mixing green-yellow into black creates gray. (Phlegm-water resides in vessels, causing slight blood stasis.) However, there is difference between transmitting and direct invasion. Transmitting heat pathogen starts as white, turns yellow, then gray-black, possibly with prickles, black spots, fissures, dryness, regardless of root or tip; purging and clearing heat is indicated. Light gray with deep black concentric rings in the center (due to long-standing cold-heat knotting, or pre-existing phlegm/fluid/blood stasis, plus new retention. If each transmission created one ring, it would be illogical; perhaps each transformation of pathogen into cold/heat/dry/damp adds a ring, or each injury from cold/heat/food/fluid adds a ring). This is warm disease heat toxin. Urgently use Liangge Shuangjie. Heat toxin transmitting once shows one ring; twice or thrice shows two or three rings. Three rings indicate untreatability. Direct invasion of Three Yin, starting without dry-heat, showing gray immediately, moist tongue without coating, not changing color, indicates internal cold-food retention, cold-phlegm/water-fluid, or blood stasis with mania. Treat according to syndrome. Also, cold with food retention, after repeated sweating/purging/digestion aids, with open bowels/bladder, but gray-black coating remains moist or not dry. Do not mistake moisture for cold and misuse Jiang/Fu Zi. Do not mistake lack of dryness for absence of need to avoid Xiaoshi/Huanglian. This is due to excessive sweating/purging damaging fluids, causing deficient fire to flare up. Pulse is deficient, minute, weak. Treatment urgently needs to nourish yin. Even without palpitations or intermittent pulse, Jiugao Gancao Tang is indicated. Contains Ganrun (sweet/moist) herbs like Shengdi, Ejiao, Huma Ren, Maidong to nourish yin and moisten dryness. Generally, if yang pathogen is hyperactive, use Xiaoshi/Huanglian to save yin; if yin-blood is exhausted, use Shengdi to nourish yin. Can this be ignored?
Red is the proper color of the Heart. Extreme red indicates warm-heat toxin accumulating in Heart/Stomach, or epidemic heat toxin internally盛. If moist, do not purge immediately; use Jiedu Tang or Baihu Tang. Red with white coating indicates contraction of out-of-season cold; Guizhi Baihu Tang is indicated. Red with two paths of gray coating indicates warm-heat with cold-food retention; Liangge San with one or two digestive herbs is indicated. Red with black coating indicates heat toxin entering Shaoyin; Dachengqi Tang combined with Baihu Tang is indicated. Extreme red with yellow-black prickles indicates heat toxin entering Fu organs; Tiaowei Chengqi Tang is indicated. Extreme red with purple-red macules and generalized maculation indicates Yang Du (Yang Toxin) entering Heart; Renshen Baihu Tang with Xijiao (Rhinoceros Horn) and Huanglian is indicated. Extreme red with fissures indicates dry-heat entering Liver; Dachengqi Tang with Chaihu and Baishao is indicated; add Qin and Lian if severe. Ulcerated/rotten indicates damp-heat entering Spleen; Xiaochengqi Tang with Qin, Lian, Banxia is indicated. White patches indicate fire blazing (superficial, not entering vessels, only appearing as white patches); Sanhuang Shigao Tang minus Mahuang is indicated. Purple ulcers indicate fire郁伏 (stagnant/deep); Jiedu Tang is indicated. Red stars (raised red beads) indicate Heart Pericardium fire flaming up; Liangge San is indicated. A type tender like new growth, looking moist but extremely dry/dehydrated internally, results from reckless sweating/purging exhausting fluids; mostly untreatable. Urgently use Shengmai San and Renshen Sanbai Tang. Tongue flaccid and immobile indicates Liver exhaustion; suddenly thin and elongated tongue indicates Heart exhaustion.
Purple indicates post-alcohol cold damage. Vulgar doctors and fools often, after catching cold, refuse herbal medicine, using ginger, scallion, and wine to sweat. If sweat is incomplete, wine toxin hides in the Heart Pericardium, often causing this syndrome. (Some transform into damp-warmth, some into wine toxin. The cause is cold binding the great exterior, wine power unable to exit outward, accumulating internally in Stomach and Pericardium.) Pure purple, or center slightly white and moist, suggests Gegen Tang (Kudzu Decoction) plus Shigao (Gypsum). Purple with red macules, or purple-dry-yellow, purple-shortened, all suggest Liangge San to purge. Entirely purple and dry, like cooked liver, is dead Liver color, with cold limbs and deep-slippery pulse (blood vessel stasis, yang depression failing to reach). This is extreme yang resembling yin. Urgently use Danggui Sini Tang (Angelica Decoction for Cold Extremities) plus Jiuhuang (Wine-processed Rhubarb) to purge. (Add Taoren/Peach Kernel.) However, mostly untreatable. (Danggui Sini Tang is still too tonifying; Huanglian is too draining. This syndrome requires dispersing, resolving stasis, unblocking vessels, opening blood, and reaching qi.) Generally, deep purple with red indicates yang-heat wine toxin; bitter-cold detoxification is suitable. (Focus on resolving stasis.) Pale purple with green-slippery indicates Kidney/Liver yin syndrome; Wuzhuyu Tang and Sini Tang should be used urgently to warm. (Should also resolve stasis.) However, there are cases with thin cyan-purple coating in center, or slight gray-black, neither dry nor wet, with urgent purging indications. This is heat pathogen injuring blood level; Xijiao Dihuang Tang plus Jiuhuang for mild purging is indicated. (Red and purple tongues refer to the tongue body; there is no such thing as red coating or purple coating. Those appearing purple are likely rotted tongue surface, or slight black coating reflecting against red, creating the illusion.)
Moldy-soybean color coating indicates cold damage with food retention. Food fills Taiyin, depressed and unable to vent, eventually becoming soybean color. Symptoms include abdominal fullness and intermittent pain; Guizhi Tang plus Zhishi, Houpo, Ju Pi, Banxia is used. Severe pain adds Dahuang. Due to undigested cold food, add Pao Jiang and Houpo; severely, Tiaowei Chengqi Tang plus Pao Jiang purges. If Stomach qi exhausts, pulse is knotted/intermittent, lips hang, teeth dry, with diarrhea, death ensues. (Note: This is also沉香色 (Sandalwood color). Always caused by blood stasis and turbid qi. Damp-heat with phlegm also commonly presents this, not just food retention.)
Blue coating indicates pure Liver color. (Vague.) Long-standing cold damage, repeatedly sweated and purged, neglected care, leads to extreme Stomach qi injury, Heart fire lacks qi, Spleen earth lacks foundation, thus Lung metal fails to generate; Liver wood lacks control, insults Spleen earth, so coating color is like indigo. Or accompanied by blue macules on body, indicating exhaustion of Heart, Spleen, Lung qi internally; death is certain. If light blue, not deep, or slight blue streaks, indicates Wood injured by Metal, organ qi not exhausted, pulse not deep-choppy but slightly wiry; treatable. (This statement is very reasonable but lacks elaboration. Deep-choppy means righteous qi does not arrive, pulse form is discontinuous/uneven. Slightly wiry means qi arrives but blood blocks it, hence tense pulse form.) Xiaochaihu Tang plus Rougui (Cinnamon Bark) and Pao Jiang is indicated. (Note: Commonly seen in epilepsy/collapse and chronic Stomach pain, whole tongue is blue. This is also blood stasis in Stomach, Liver qi not soothing. Thus cyan, black, blue, crimson are all called turbid, involving blood level. Must differentiate cold/heat, dry/damp, phlegm/blood, retained food/dry stool, masses, treating primarily by loosening blood level.) Although tongue syndromes are numerous, they do not exceed eight coating colors. Summarizing the essentials assists in differentiation. (Zhang Shiwen, *Shanghan Xulun*.)