伤寒自表传里。温热自里达表。全以舌苔为验。传里浅深。及里结多寡。亦以舌苔
为验。里热渐清。谷气渐进。亦以舌苔为验。试先举观舌形之要诀。
凡舌膜由三焦腠理直接胃肠。舌本由经络直通心脾肾。故舌尖主上脘。亦主心。舌中主
中脘。统主胃与小肠。舌根主下脘。亦主肾与大肠。四边属脾。此为观形分部之要诀。
【荣斋按】舌苔两字，当分别看。舌是舌的本质，苔是舌上所生的垢腻。舌以候元
气的盛衰，苔以察病症之浅深。至于分部，可区别为五∶（1）舌尖──候上焦心肺之
疾。（2）舌中央──候胃与大小肠之疾。（3）舌根──候肾与二便之疾。（4）舌旁
──左以候肝胆之疾，右以候脾肺之疾。（5）舌边──候三焦膜原与两胁之疾。这里，
以前后分三部，察上中下三焦；以旁边分两部，察左右两方。它与脉位之前以候前，后
以候后，理相一贯。由于经验的证明，心热则舌尖红而起刺，胃有积滞则中腻，脾肾虚
寒则根滑而白，肝胆湿热则舌旁黄腻，三焦蕴火，或湿温伏邪，则苔虽白而舌边必红绛
；方寸之地，部位分明，是信而有征的。
凡出舌长而尖者。热未甚。尚宜透邪。出舌圆而平者。热已甚。急宜清热。出舌短。不
能出齿外而形方者。热盛极。速宜泻火。若女劳复及产后坏症。舌出数寸者必死。又
当别论。此为观验出舌之要诀。
凡舌伸之无力者。中气虚。宜补中。满伸似有线吊者。舌系燥。宜润燥。麻木而伸
不出者。肝风挟痰。宜熄风化痰。伸以 唇者。心脾热。宜泻火清热。伸出弄唇者。中
蛇毒。宜解毒。伸出不收者。脾涎浸。宜控涎。如舌缩而边卷者。胃液燥极。宜清胃润
燥。润之而舌仍卷者。病去而舌气未和。尚可养营益气。若卷而缩短者。厥阴气绝。舌质
痿缩也。不治。垢腻揩去而舌仍缩者。亦不治。此为观舌伸缩之要诀。
凡舌颤掉不安者。曰舌战。由气虚者蠕蠕微动。由肝风者习习煽动。宜参舌色以辨
之。如色深红鲜红而战者。宜凉血熄风。紫红瘀红而战者。宜泻火熄风。嫩红而战者。
宜养血熄风。淡红而战者。宜峻补气血。若舌软而不能动
者。曰舌痿。有暴痿久痿之别。暴痿多由于热灼。每现于舌干之时。亦宜辨其舌色。
如色深红而痿者。宜清营兼益气。紫红而痿者。宜清肝兼通腑。鲜红而痿者。宜滋阴兼
降火。惟色淡红而痿者。宜大补气血。如病久而舌色绛嫩者。阴亏已极。津气不能分布
于舌本。无药可治。此为观舌痿战之要诀。
【廉勘】久病舌痿。由舌筋之麻痹。及舌实质之痿缩而来。或偏侧。或偏瘫。则又
为神经软瘫。如延髓球麻痹。脊髓性筋肉痿缩等症。治宜大补气血。或可侥幸于什一。
至舌挺出时振颤者。多见于温热病及酒客神经衰弱症。
凡病而有苔者多里滞。宜导滞。无苔者多中虚。宜补中。病本无苔而忽有者。胃浊
上泛。宜泄浊。病本有苔而忽无者。胃阴将涸。宜救阴。其苔半布者。有偏外、偏内、
偏左、偏右之别。偏外者外有内无。邪虽入里未深。而胃气先匮。宜祛邪兼益胃。偏
内者内有外无。胃滞虽减。而肠积尚存。宜通肠兼消滞。素有痰饮者。亦多此苔。宜蠲
饮。偏左者左有右无。偏右者右有左无。皆半表半里症。但看苔色之多少。白色多。表症多
。但宜和解佐温佐清。随症酌加。黄黑灰多。或生芒刺。及黑点燥裂。则里热已结。急
宜和解兼下。又有从根至尖。直分两条者。则合病与夹阴寒症。从根至尖。横分两三截
者。是并病症也。均宜随症用药。苔虽有形可据。皆为偏而不全。即全舌其苔满布者。
虽多湿痰食滞。亦宜辨其为白砂苔。兼四边舌肉紫红者。为湿遏热伏之温邪。伏于膜原
。急宜达原以透邪。白碱苔。兼四边舌肉皆腻者。为脾胃湿阻气滞。与食积相搏。急宜
芳淡兼消导。此为观舌有无积苔。及苔偏全之要诀。
凡舌有断纹裂纹。如人字川字爻字及裂如直槽之类。虽多属胃燥液涸。由于实热内逼
。急宜凉泻以清火。然中有直裂者。多属胃气中虚。却宜补阴益气。切忌凉泻。更有本
无断纹。而下后反见人字裂纹者。此属肾气凌心。急
宜纳气补肾。若苔点如粞者。虫蚀居多。即苔现槟榔纹。隐隐有点者。亦属虫积。皆宜
杀虫祛积。此为观舌断纹细点之要诀。
【廉勘】舌上面本有细点如刺。名曰味蕾。主辨味。无火则平如无点。有火则突而
起点。究竟有虫与否。还宜详审现症确凿。始可投杀虫祛积之剂。
凡苔起瓣晕。皆脏腑实火熏蒸。多见于温毒温疫等病。瓣则黑色居多。晕则灰黑色
居多。瓣有多少。一二瓣尚轻。三四瓣已重。六七瓣极重而难治。晕有层数。一晕尚轻。
二晕为重。三晕多死。亦有横纹二三层者。与此不殊。宜泻火解毒。急下存阴。服至瓣
晕退净。而其人气液渐复者。庶能救活。此为观舌瓣晕之要诀。
凡舌肿胀增大。不能退场门者。须参舌色以辨之。如色白滑黑滑者。多由于水气浸淫
。宜通阳利水。黄腻满布者。由湿热郁而化毒。毒延于口。宜大泻湿火以祛毒。紫暗者
。多由于酒毒冲心。心火炎上。宜泻火通瘀。白腻黄腻者。多由于痰浊相搏。满则上溢
。宜蠲痰泄浊。若舌瘦小。甚则瘪薄者。亦须兼辨其色。淡红嫩红者。心血内亏。宜养
血补心。紫绛灼红者。内热风消。宜清热熄风。若色干绛。甚则紫黯如猪腰色者。皆由
心肝血枯。舌质萎缩。不治。此为观舌胀瘪之要诀。
凡舌斜偏一边者为舌歪。色紫红而势急者。多由于肝风发痉。宜熄风镇痉。色淡红
而势缓者。多由于中风偏枯。歪在左。宜养血益气。从阴引阳。歪在右。宜补气舒筋。从
阳引阴。然多不治。若舌有血痕伤迹者为舌碎。其因有四。一因舌衄。二因抓伤。三因
溃疡。四因斑痕。各宜对症施治。此为观舌歪碎之要诀。
凡舌起瘰而凸者。多见于温病、热病、温毒、时疫等证。皆属胃肠实热。枭毒内伏
。急宜大剂凉泻。速攻其毒。若凹陷而有缺点者。其症有虚有实。实者多由于口糜。厥后舌起糜点。糜点脱去。则现凹点。由于霉毒上升者宜去霉解毒。由于胃肾阴虚。浊腐蒸腾者。宜救阴去腐。果能毒去腐褪。则新肉渐生。凹点自满。虚者由胃阴中竭。心气不能上布于舌本。气盛则凸。气陷则凹。眼眶亦然。不独舌起凹点也。病已不治。可按脉证以决死期。此为观舌凸凹之要诀。
廉勘∶凡舌起瘰而突者。即舌上乳嘴肿。当辨其为热毒。为癌肿。为霉毒性护膜肿。此为最要，若舌起凹点者。多由于乳嘴凹陷。当辨其舌生溃疡。及霉毒性溃疡，如无。则为脏形痿顿。乳嘴缩小成凹，决无方法可治。
伤寒病邪从体表传入体内。温热病邪从体内透达体表。全凭舌苔的变化来验证。病邪传入体内的深浅程度，以及体内邪气结聚的多少，也通过舌苔来验证。体内的热邪逐渐清除，谷气（脾胃运化之气）逐渐恢复，同样以舌苔的变化作为验证依据。现在先列举观察舌形的主要诀窍。
大凡舌膜由三焦腠理直接连接胃肠。舌根由经络直通心、脾、肾。因此，舌尖主要对应上脘，也对应心脏；舌中部主要对应中脘，统管胃与小肠；舌根部主要对应下脘，也对应肾脏与大肠；舌的四周边缘属于脾脏。这是观察舌形分部的主要诀窍。
【徐荣斋按语】“舌苔”这两个字，应当分开来看。“舌”是舌的本质，“苔”是舌面上生长的垢腻物。通过舌质可以候察元气的盛衰，通过舌苔可以察知病症的浅深。至于分部诊断，可以分为五类：（1）舌尖——候察上焦心肺的疾病。（2）舌中央——候察胃与大小肠的疾病。（3）舌根——候察肾与二便（大小便）的疾病。（4）舌旁——左侧候察肝胆的疾病，右侧候察脾肺的疾病。（5）舌边——候察三焦膜原与两胁的疾病。这里，以前后分为三部，察看上、中、下三焦；以旁边分为两部，察看左右两方。这与脉诊部位前部候前、后部候后的道理是一致的。由于经验的证明，心热则舌尖红且起刺，胃有积滞则舌中苔腻，脾肾虚寒则舌根滑而白，肝胆湿热则舌旁苔黄腻，三焦蕴火，或湿温伏邪，则苔虽白但舌边必呈红绛色；方寸之地，部位分明，这是确凿可信的。
凡是伸出的舌头长而尖者，说明热邪不严重，尚宜透发邪气。伸出的舌头圆而平者，说明热邪已经很重，急宜清热。伸出的舌头短，不能伸出齿外且形状方正者，说明热邪极盛，速宜泻火。如果是女劳复（因房事导致的伤寒复发）及产后坏症，舌头伸出数寸者，必定死亡。这又当别论。这是观察验查舌头伸出形态的主要诀窍。
凡是舌头伸出无力者，是中气虚，宜补中气。舌头完全伸出似有线吊着者，是舌系带干燥，宜润燥。舌头麻木而伸不出者，是肝风挟痰，宜熄风化痰。舌头伸出时咬唇者，是心脾热，宜泻火清热。舌头伸出并弄唇者，是中了蛇毒，宜解毒。舌头伸出后不能收回者，是脾涎浸渍，宜控涎（控制痰涎）。如果舌头收缩且边缘卷曲者，是胃液极度干燥，宜清胃润燥。滋润之后舌头仍然卷曲者，是病邪已去但舌气未和，还可以养营益气。如果舌头卷曲且缩短者，是厥阴经气绝，舌质痿缩，不治。垢腻刮去后舌头仍然收缩者，也不治。这是观察舌头伸缩的主要诀窍。
凡是舌头颤抖不安者，称为“舌战”。由气虚引起的，微微蠕动；由肝风引起的，习习煽动。宜结合舌色来辨别。如舌色深红、鲜红而颤抖者，宜凉血熄风；紫红、瘀红而颤抖者，宜泻火熄风；嫩红而颤抖者，宜养血熄风；淡红而颤抖者，宜峻补气血。如果舌头柔软而不能活动者，称为“舌痿”。有暴发性痿软和久病痿软的区别。暴发性痿软多由于热邪灼伤，常出现在舌干之时，也宜辨别其舌色。如舌色深红而痿软者，宜清营兼益气；紫红而痿软者，宜清肝兼通腑；鲜红而痿软者，宜滋阴兼降火。只有舌色淡红而痿软者，宜大补气血。如果病久且舌色绛嫩者，是阴亏已极，津气不能分布于舌本，无药可治。这是观察舌痿、舌战的主要诀窍。
【廉勘按语】久病舌痿，是由于舌筋麻痹及舌实质萎缩而来。如果偏侧或偏瘫，则是神经软瘫，如延髓球麻痹、脊髓性肌肉萎缩等症。治疗宜大补气血，或许能有十分之一的治愈希望。至于舌头挺出时振颤者，多见于温热病及酒客神经衰弱症。
凡是生病而有舌苔的多为里有停滞，宜导滞。没有舌苔的多为中气虚弱，宜补中。病本无苔而忽然出现的，是胃浊上泛，宜泄浊。病本有苔而忽然消失的，是胃阴将枯竭，宜救阴。其苔只有一半分布的，有偏外、偏内、偏左、偏右的区别。偏外的，外部有苔内部无苔，邪气虽然入里但未深入，而胃气先已匮乏，宜祛邪兼益胃。偏内的，内部有苔外部无苔，胃滞虽然减少，而肠中积滞尚存，宜通肠兼消滞。素有痰饮的人，也多出现这种半布苔，宜蠲饮（祛除痰饮）。偏左的，左边有苔右边无苔；偏右的，右边有苔左边无苔，这都是半表半里证。只看苔色的多少，白色多的，表证多，只宜和解佐以温法或清法，随症酌加。黄色、黑色、灰色多的，或生芒刺，及黑点燥裂，则里热已经结聚，急宜和解兼用下法。又有从舌根至舌尖，直分两条的，则是合病与夹阴寒证。从舌根至舌尖，横分两三截的，是并病症。都宜随症用药。苔虽然有形可据，但皆为偏而不全。即使全舌其苔满布，虽然多为湿痰食滞，也宜辨其为白砂苔，兼四边舌肉紫红的，是湿遏热伏的温邪，伏于膜原，急宜达原以透邪。白碱苔，兼四边舌肉皆腻的，是脾胃湿阻气滞，与食积相搏，急宜芳淡兼消导。这是观察舌有无积苔及苔偏全的主要诀窍。
凡是舌面有断纹裂纹，如人字、川字、爻字及裂如直槽之类，虽然多属胃燥液涸，由于实热内逼，急宜凉泻以清火。然而中间有直裂的，多属胃气中虚，却宜补阴益气，切忌凉泻。更有原本无断纹，而下法治疗后反而出现人字裂纹的，这属肾气凌心，急宜纳气补肾。如果苔点如米粒状者，多是虫蚀居多，即苔现槟榔纹，隐隐有点的，也属虫积，皆宜杀虫祛积。这是观察舌断纹细点的主要诀窍。
【廉勘按语】舌上面本来有细点如刺，名叫味蕾，主辨味。无火时平坦如无点，有火时突起有点。究竟是否有虫，还宜详细审察现症确凿，始可投用杀虫祛积之剂。
凡是舌苔起瓣晕，都是脏腑实火熏蒸，多见于温毒、温疫等疾病。瓣则黑色居多，晕则灰黑色居多。瓣有多少，一二瓣尚轻，三四瓣已重，六七瓣极重而难治。晕有层数，一晕尚轻，二晕为重，三晕多死。也有横纹二三层者，与此相似。宜泻火解毒，急下存阴。服药至瓣晕退净，而其人气液渐复者，庶能救活。这是观察舌瓣晕的主要诀窍。
凡是舌头肿胀增大，不能退回口腔者，须参看舌色来辨别。如舌色白滑、黑滑的，多由于水气浸淫，宜通阳利水。黄腻满布的，由湿热郁而化毒，毒延于口，宜大泻湿火以祛毒。紫暗的，多由于酒毒冲心，心火炎上，宜泻火通瘀。白腻黄腻的，多由于痰浊相搏，满则上溢，宜蠲痰泄浊。如果舌头瘦小，甚至瘪薄者，也须兼辨其色。淡红、嫩红的，是心血内亏，宜养血补心。紫绛、灼红的，是内热风消，宜清热熄风。如果舌色干绛，甚至紫黯如猪腰颜色的，皆由心肝血枯，舌质萎缩，不治。这是观察舌胀瘪的主要诀窍。
凡是舌头斜偏一边者为舌歪。色紫红而发病急的，多由于肝风发痉，宜熄风镇痉。色淡红而发病缓的，多由于中风偏枯，歪在左侧，宜养血益气，从阴引阳；歪在右侧，宜补气舒筋，从阳引阴。然而大多不治。如果舌头有血痕伤迹者为舌碎。其原因有四：一因舌衄（舌出血），二因抓伤，三因溃疡，四因斑痕。各宜对症施治。这是观察舌歪碎的主要诀窍。
凡是舌起瘰（颗粒状凸起）而凸者，多见于温病、热病、温毒、时疫等证。皆属胃肠实热，枭毒内伏，急宜大剂凉泻，速攻其毒。若凹陷而有缺点者，其症有虚有实。实者多由于口糜，厥逆后舌起糜点，糜点脱去，则现凹点。由于霉毒上升者宜去霉解毒；由于胃肾阴虚，浊腐蒸腾者，宜救阴去腐。果能毒去腐褪，则新肉渐生，凹点自满。虚者由胃阴中竭，心气不能上布于舌本，气盛则凸，气陷则凹，眼眶亦然，不独舌起凹点也。病已不治，可按脉证以决死期。这是观察舌凸凹的主要诀窍。
廉勘按语：凡是舌起瘰而突者，即舌上乳嘴肿。当辨其为热毒、癌肿、霉毒性护膜肿。此为最要。若舌起凹点者，多由于乳嘴凹陷。当辨其舌生溃疡，及霉毒性溃疡，如无，则为脏形痿顿，乳嘴缩小成凹，决无方法可治。
Cold damage (Shanghan) pathogens transmit from the exterior to the interior. Warm-heat pathogens reach from the interior to the exterior. Verification relies entirely on the tongue coating (tongue moss). The depth of transmission into the interior and the quantity of interior accumulation are also verified by the tongue coating. As interior heat gradually clears and grain qi (Spleen-Stomach transformation qi) gradually advances, this is likewise verified by the tongue coating. Now, let us first enumerate the essential principles for observing tongue shape.
Generally, the tongue membrane connects directly with the stomach and intestines via the Sanjiao (Triple Burner) cou li (interstices). The tongue root connects directly to the Heart, Spleen, and Kidney via the meridians. Therefore, the tongue tip primarily corresponds to the upper epigastrium (Shangwan) and also to the Heart; the tongue center primarily corresponds to the middle epigastrium (Zhongwan), governing the Stomach and Small Intestine; the tongue root primarily corresponds to the lower epigastrium (Xiawan) and also to the Kidneys and Large Intestine; the four sides belong to the Spleen. This is the essential principle for observing tongue shape distribution.
[Commentary by Xu Rongzhai]: The term "tongue coating" should be viewed separately. "Tongue" refers to the essence of the tongue body, while "coating" refers to the greasy deposit growing on the tongue surface. The tongue body reflects the prosperity or decline of Yuan Qi (Primordial Qi), while the coating reveals the depth of the disease. Regarding distribution, it can be distinguished into five categories: (1) Tongue tip—observes diseases of the Upper Jiao (Heart and Lungs). (2) Tongue center—observes diseases of the Stomach and Large/Small Intestines. (3) Tongue root—observes diseases of the Kidneys and bowel/bladder functions. (4) Tongue sides—left side observes Liver/Gallbladder diseases, right side observes Spleen/Lung diseases. (5) Tongue edges—observe Sanjiao Mo Yuan (Membrane Source) and hypochondriac diseases. Here, dividing front and back into three parts allows observation of the Upper, Middle, and Lower Jiao; dividing the sides into two parts allows observation of the left and right aspects. This is consistent with the principle of pulse diagnosis where the anterior position observes the front and posterior position observes the back. Empirical evidence proves that Heart heat causes the tongue tip to be red with prickles; Stomach stagnation causes a greasy coating in the center; Spleen/Kidney deficiency-cold causes a slippery white coating at the root; Liver/Gallbladder damp-heat causes a yellow greasy coating on the sides; Sanjiao fire accumulation or latent damp-warmth pathogens cause the coating to remain white but the tongue edges to become crimson; within this square inch, locations are distinct, which is reliable and verifiable.
When the protruding tongue is long and pointed, the heat is not severe, and expelling pathogens through diffusion is appropriate. When the protruding tongue is round and flat, the heat is severe, and clearing heat urgently is required. When the protruding tongue is short, cannot extend beyond the teeth, and appears square-shaped, the heat is extremely intense, and purging fire urgently is required. However, in cases of female labor relapse (relapse due to sexual activity after cold damage) and postpartum complicated conditions, if the tongue extends several inches, death is certain. This is a separate discussion. This is the essential principle for observing the protrusion of the tongue.
When the tongue extends with weakness, it indicates deficiency of Middle Qi (Spleen/Stomach Qi), requiring tonification of the Middle. When the tongue extends fully as if suspended by a thread, the lingual frenulum is dry, requiring moistening of dryness. When the tongue is numb and cannot extend, it indicates Liver Wind carrying Phlegm, requiring extinguishing of Wind and transformation of Phlegm. When the tongue extends and bites the lips, it indicates Heart/Spleen Heat, requiring purging of Fire and clearing of Heat. When the tongue extends and manipulates the lips, it indicates snake venom poisoning, requiring detoxification. When the tongue extends but cannot retract, it indicates flooding of Spleen saliva, requiring control of Phlegm-fluids. If the tongue shrinks and curls at the edges, it indicates extreme dryness of Stomach fluids, requiring clearing of the Stomach and moistening of dryness. If moistening does not uncurl the tongue, the pathogen has departed but the tongue's Qi is not yet harmonious, allowing for nourishment of Ying (Nutrient) Qi and tonification of Qi. If the tongue curls and shortens, it indicates exhaustion of Jueyin (Liver/Pericardium) Qi and flaccidity of the tongue substance, which is untreatable. If the tongue remains shrunken even after scraping off the coating, it is also untreatable. This is the essential principle for observing tongue extension and retraction.
When the tongue trembles restlessly, it is called "Tongue Tremor." Caused by Qi deficiency, it moves slightly; caused by Liver Wind, it flutters vigorously. Differentiation should rely on tongue color. If deep red or fresh red and trembling, cooling Blood and extinguishing Wind is appropriate. If purple-red or stasis-red and trembling, purging Fire and extinguishing Wind is appropriate. If tender red and trembling, nourishing Blood and extinguishing Wind is appropriate. If pale red and trembling, vigorous tonification of Qi and Blood is appropriate. If the tongue is soft and immobile, it is called "Tongue Flaccidity." There are acute and chronic forms. Acute flaccidity is mostly due to heat scorching, often appearing when the tongue is dry; differentiation by color is also needed here. If deep red and flaccid, clearing the Ying Level and supplementing Qi is appropriate. If purple-red and flaccid, clearing the Liver and unblocking the Fu organs is appropriate. If fresh red and flaccid, nourishing Yin and descending Fire is appropriate. Only if pale red and flaccid, major tonification of Qi and Blood is appropriate. If the disease is prolonged and the tongue color is crimson and tender, Yin deficiency is extreme, Jin-Ye (Body Fluids) and Qi cannot distribute to the tongue root, and there is no treatment. This is the essential principle for observing tongue flaccidity and tremor.
[Lian Kan Commentary]: Chronic tongue flaccidity results from paralysis of the tongue muscles and atrophy of the tongue substance. If unilateral or hemiplegic, it constitutes neurological flaccid paralysis, such as bulbar palsy or spinal muscular atrophy. Treatment should involve major tonification of Qi and Blood, offering perhaps a one-in-ten chance of recovery. Tongue protrusion with tremors are commonly seen in warm-heat diseases and neurasthenia in alcoholics.
Diseases with a tongue coating usually indicate interior stagnation, requiring guiding out stagnation. Diseases without a coating usually indicate Middle deficiency, requiring tonification of the Middle. If a patient originally without a coating suddenly develops one, it indicates turbid Stomach Qi rising, requiring draining of turbidity. If a patient originally with a coating suddenly loses it, Stomach Yin is about to dry up, requiring rescue of Yin. Coatings distributed only partially may be external/internal or left/right. External predominance (coating outside, none inside) suggests pathogen entered interior but not deeply, while Stomach Qi is deficient; expelling pathogens and benefiting Stomach Qi is appropriate. Internal predominance (coating inside, none outside) suggests Stomach stagnation reduced but intestinal accumulation remains; unblocking intestines and eliminating stagnation is appropriate. Patients with chronic Phlegm-fluids often have this type of partial coating, requiring elimination of fluids. Left-predominant (coating left, none right) or right-predominant (coating right, none left) both indicate Shaoyang (Half-Exterior/Half-Interior) patterns. Observe the quantity of coating color: abundant white indicates exterior patterns, suitable for harmonizing with warming or clearing adjuncts, adjusted to symptoms. Abundant yellow, black, or gray colors, or presence of prickles, black dots, and dry cracks, indicate interior heat consolidation; urgent harmonizing with purgation is required. A coating divided straight down the middle from root to tip indicates combined disease and internal cold. Horizontal division into two or three sections from root to tip indicates concurrent diseases. Medication should be prescribed according to symptoms. Although coatings have visible form, they are always partial and incomplete. Even if the entire tongue is covered, indicating damp-phlegm or food stagnation, one must differentiate white sandy coating accompanied by purple-red tongue flesh on the four sides, which indicates warm pathogens suppressed by dampness and lying latent in the Mo Yuan (Membrane Source); urgent resolution of the Mo Yuan to expel pathogens is required. White alkaline coating accompanied by greasy tongue flesh on the four sides indicates Spleen/Stomach damp obstruction and Qi stagnation struggling with food accumulation; urgent aromatic-diffusing and light-draining with digestion-promoting methods is required. This is the essential principle for observing the presence/absence of accumulated coating and its partial/full distribution.
Cracks and fissures on the tongue, resembling characters like 'Ren', 'Chuan', 'Yao', or straight grooves, mostly indicate Stomach dryness and fluid exhaustion due to internal逼迫 (forcing) by excess heat; urgent cooling purgation to clear Fire is required. However, a straight crack in the center mostly indicates deficiency of Stomach Qi, requiring tonification of Yin and Qi, strictly avoiding cooling purgation. Furthermore, if a patient originally without cracks develops a 'Ren' character crack after purgation, this indicates Kidney Qi harassing the Heart; urgent gathering of Qi and tonification of the Kidney is required. If coating spots resemble rice grains, it mostly indicates worm infestation. If the coating shows betel-nut-like patterns with hidden spots, it also indicates worm accumulation; killing worms and removing accumulation is appropriate. This is the essential principle for observing tongue cracks and fine spots.
[Lian Kan Commentary]: The tongue naturally has fine points like prickles, named taste buds (papillae), responsible for taste perception. Without Fire, they are flat; with Fire, they protrude. Whether worms are present requires careful examination of current symptoms before administering vermifuge and accumulation-removing agents.
Coating forming patches and halos are all caused by steaming from excess Fire of the Zang-Fu organs, commonly seen in warm-toxin and warm-plague diseases. Patches are mostly black; halos are mostly gray-black. Fewer patches (1-2) are mild; 3-4 are severe; 6-7 are extremely severe and difficult to treat. Halos have layers; one layer is mild, two layers are severe, three layers often lead to death. Transverse lines of two or three layers are similar. Purging Fire and detoxifying, urgent purgation to preserve Yin, are required. If the patches and halos recede completely and the patient's Qi and fluids gradually recover, survival is possible. This is the essential principle for observing tongue patch-halos.
Swollen and enlarged tongues that cannot retreat into the mouth require differentiation by color. White slippery or black slippery colors mostly indicate water flooding, requiring unblocking Yang and promoting urination. Yellow greasy full coverage indicates damp-heat郁 (stagnating) transforming into toxin spreading to the mouth; major purging of damp-fire to remove toxin is required. Purple-dark colors mostly indicate wine toxin rushing to the Heart with Heart Fire flaming upward; purging Fire and unblocking stasis is required. White greasy mixed with yellow greasy indicates fighting between turbid Phlegm overflowing upwards; eliminating Phlegm and draining turbidity is required. Thin, small, or sunken/thin tongues also require color differentiation. Pale red or tender red indicates internal deficiency of Heart Blood, requiring nourishing Blood and tonifying the Heart. Purple-crimson or burning red indicates internal wind and heat consuming fluids; clearing Heat and extinguishing Wind is required. Dry crimson colors, or even purple-dark like pig kidney color, indicate exhaustion of Heart/Liver Blood and tongue substance atrophy, which is untreatable. This is the essential principle for observing tongue swelling and sunkenness.
A tongue deviating to one side is called "Tongue Deviation." Purple-red with rapid onset mostly indicates Liver Wind causing spasms, requiring extinguishing of Wind and calming spasms. Pale red with slow onset mostly indicates stroke hemiplegia. Deviation to the left requires nourishing Blood and tonifying Qi, drawing Yang from Yin; deviation to the right requires tonifying Qi and relaxing sinews, drawing Yin from Yang. However, these are mostly untreatable. A tongue with blood marks or injuries is called "Broken Tongue." Causes include four types: one, tongue bleeding (She Nu); two, scratching injury; three, ulceration; four, macular scars. Each requires symptomatic treatment. This is the essential principle for observing tongue deviation and breakage.
Tongues with nodules (lumps) and convexity are commonly seen in warm diseases, heat diseases, warm toxins, and seasonal epidemics. All belong to excess heat in the Stomach and Intestines with lurking toxic pathogens; urgent large-dose cooling purgation to rapidly attack the toxin is required. If concave with defects, the syndrome can be excess or deficiency. Excess cases mostly result from oral thrush (Kou Mi); after Jueyin reversal, nodule points appear on the tongue, and after shedding, concave points remain. Rising mold-toxin requires removal of mold and detoxification; Stomach/Kidney Yin deficiency with steaming of turbid decay requires rescuing Yin and removing decay. If toxin is removed and decay fades, new flesh grows and concavities fill. Deficiency cases result from exhaustion of Stomach Yin and inability of Heart Qi to distribute to the tongue root; Qi surplus causes convexity, Qi sinking causes concavity, similarly affecting eye sockets, not just the tongue. The disease is untreatable; death time can be determined by pulse and symptoms. This is the essential principle for observing tongue convexity and concavity.
Lian Kan Commentary: Tongue nodules and protrusions refer to swollen lingual papillae. One must differentiate between heat-toxin, cancerous tumors, and mycotic pseudomembranous swelling. This is crucial. Tongue concavities mostly result from depressed papillae. One must differentiate tongue ulcers and mycotic ulcers; if absent, it represents visceral atrophy and papillary shrinkage into concavity, for which there is absolutely no treatment method.