陈士铎曰。伤寒病。凡见舌系白苔者。邪火未甚也。小柴胡解之。黄色者。心热也。用黄连、
山栀。黄而带灰色者。胃热也。石膏、知母。黄而带红者。小肠膀胱热也。用山栀。若红而白者。
肺热也。黄芩、苏叶。黑而带红者。肾虚挟邪也。生地、元参。又入柴胡。红而有黑星者。胃热极
也。元参、葛根。红而有白点者。心中有邪也。柴胡、黄连。心肝同治也。红而有大红点者。胃热带
湿也。茵陈五苓散。盖水湿必归膀胱以散邪。非肉桂不能引入膀胱。但只可一二分。不可多入。白
而带黑点。亦胃热也。宜石膏。黄而有黑者。肝经实热也。山栀、柴胡。白而黄者。邪将入里也。
山栀、柴胡解之。不使入里。柴胡乃半表半里。不可不用之药也。舌中白而外黄者。邪入大肠也。
五苓散以分水。水分则泄止矣。舌中黄而外白者。邪在内而非外。在上而非下。只可加柴胡、枳壳。
不可轻用大黄。舌根黄而光白。亦胃热带湿也。石膏为君。少加猪苓、泽泻。舌黄而隔一瓣一瓣
者。邪热深入大肠。急用大黄、茵陈。不可用抵当十枣。若下已迟。则不得不用之。然亦须辨水与
血。下水十枣。下血抵当也。舌有红中如虫蚀者。水未升而火来乘也。黄连、柴胡和解。红而裂如
人字者。邪初入心也。石膏、黄连。舌根黑而尖带红者。肾中有邪未散也。柴胡、山栀。舌根黑而
尖白者。胃火乘肾也。石膏、元参、知母。不必问其渴与不渴及下利也。舌根黑而尖黄者。邪将入
肾也。其腹痛拒按。急用大黄。否亦只用山栀、柴胡。舌纯红独尖黑者。肾虚邪火来乘也。元参或
一二两。多有生者。忌石膏。中心红晕。四围边旁纯黑者。君相二火炎腾也。急用大黄。加生地两
许。十可救五六。中央灰色。四边微红者。邪结大肠也。下之则愈。不应则死。以肾水枯槁。不可
竟用熟地补肾。盖邪未散。补则愈加胀急。必邪下而后以生地滋之。然亦不可多用也。纯灰色中间
独两晕黑者。亦邪将入肾也。急用元参两许。少加柴胡。外红而内黑者。火极似水也。急用柴胡、
山栀、大黄、枳实。若更见刺。则火亢之极矣。尤须多用
前药。总之。内黑而外白。内黑而外黄。皆前症也。与上同治。十中亦可生四五。惟舌中淡黑。而
外或淡红。外或淡白。内或淡黄。较前少轻。俱可以前法治之。十可生七八。舌纯红而露黑纹数条
者。此水来乘火。乃阴症也。其舌苔必滑。必恶寒恶水。水下喉必吐。倘见纯黑之舌。乃必死也。
不必治。水极似火。火极似水。一带纯黑。俱不可治。伤寒知验舌之法。便有把握。庶不致临症差
误耳。
李中梓曰。舌纯黑有二种。皆死症也。有火极似水者。为热极。大承气汤。有水来克火者。为
寒极。脉症必寒。附子理中汤。舌上白苔。小柴胡汤。舌上滑苔。小柴胡去半夏加人参栝蒌汤。
陈士铎说：伤寒病，凡是舌面上出现白色苔的，说明邪火并不严重。用小柴胡汤来和解表里。舌苔呈黄色的，是心热，用黄连、山栀（栀子）。舌苔黄而带灰色的，是胃热，用石膏、知母。舌苔黄而带红色的，是小肠和膀胱有热，用山栀。如果舌色红而苔白，是肺热，用黄芩、苏叶。舌色黑而带红的，是肾虚兼夹邪气，用地黄、玄参，并加入柴胡。舌色红而有黑色星点的，是胃热到了极点，用玄参、葛根。舌色红而有白色点的，是心中有邪气，用柴胡、黄连，这是心肝同治的方法。舌色红而有大红点的，是胃热兼夹湿气，用茵陈五苓散。因为水湿必然归并于膀胱以发散邪气，非肉桂不能引导药力进入膀胱，但肉桂只需加入一二分，不可多放。舌苔白而有黑点的，也是胃热，宜用石膏。舌苔黄而有黑色的，是肝经实热，用山栀、柴胡。舌苔白而转黄的，说明邪气将要入里，用山栀、柴胡来解之，防止邪气入里。柴胡是针对半表半里证的药物，是不可不用的。舌中部白而边缘黄的，说明邪气已进入大肠，用五苓散来分利水湿，水湿分利则泄泻自止。舌中部黄而边缘白的，说明邪气在内而不在外，在上而不在下，只能加柴胡、枳壳，不可轻易使用大黄。舌根部黄而中间光白，也是胃热兼夹湿气，以石膏为君药，少加猪苓、泽泻。舌苔黄且呈现一瓣一瓣隔开的样子，说明邪热深入大肠，急用大黄、茵陈，此时不可用抵当汤或十枣汤。如果攻下已经太迟，那就不得不使用抵当汤或十枣汤了。然而也必须辨别是水结还是血结，十枣汤用于下水，抵当汤用于下血。舌面红色中间像被虫蚀一样的，是水气未升而火气来乘，用黄连、柴胡和解。舌色红而裂纹像“人”字的，是邪气刚初入心，用石膏、黄连。舌根黑而舌尖带红的，是肾中有邪气未散，用柴胡、山栀。舌根黑而舌尖白的，是胃火乘袭肾脏，用石膏、玄参、知母。此时不必询问患者是否口渴及是否有下利症状。舌根黑而舌尖黄的，是邪气将要入肾，如果腹痛拒按，急用大黄；否则只用山栀、柴胡。舌色纯红唯独舌尖黑的，是肾虚导致邪火来乘，可用玄参一两甚至更多，玄参多有生用者，忌用石膏。舌中心红晕，四周围边纯黑的，是君火和相火炎腾，急用大黄，加生地约一两，十人中可救活五六人。舌中央灰色，四周边微红的，是邪气结于大肠，攻下则可痊愈，若攻下无效则会死亡，这是因为肾水枯槁，不可直接用熟地补肾。因为邪气未散，补益只会使胀满急迫加重，必须等邪气下行后，再用生地滋养。然而生地也不可用太多。舌色纯灰中间唯独有两圈黑色的，也是邪气将要入肾，急用玄参一两，少加柴胡。舌外红内黑的，是火极似水的表现，急用柴胡、山栀、大黄、枳实。如果更见到芒刺，则是火亢盛到了极点，尤其需要多用前面的药物。总之，内黑外白、内黑外黄的情况，都按照前面的病症治疗，十人中也可救活四五人。只有舌中淡黑，而外部或淡红、或淡白、内部或淡黄的，比前述情况稍轻，都可以用前面的方法治疗，十人中可救活七八人。舌纯红而露出几条黑色纹理的，这是水来乘火，属于阴证。其舌苔必定滑润，必定恶寒恶水，水入口必呕吐。倘若见到纯黑的舌头，那是必死的征象，不必治疗。水极似火，火极似水，只要舌上带有一圈纯黑，都不可治。学习伤寒病懂得通过验舌来判断病情，就有把握，才不会在临症时出现差错。
李中梓说：舌色纯黑有两种情况，都是死证。一种是火极似水，属于热极，用大承气汤。另一种是水来克火，属于寒极，脉象和症状必定表现为寒，用附子理中汤。舌上有白苔的，用小柴胡汤。舌上有滑苔的，用小柴胡汤去掉半夏，加入人参、栝蒌。
Chen Shiduo stated: In Shaoyang disease (Shaoyang illness), if a white coating is seen on the tongue, it indicates that the pathogenic fire is not severe. Use Xiao Chai Hu Tang (Minor Bupleurum Decoction) to harmonize the exterior and interior. If the coating is yellow, it indicates Heart heat; use Huang Lian (Coptidis Rhizoma) and Shan Zhi (Gardeniae Fructus). If the coating is yellow with a grayish tint, it indicates Stomach heat; use Shi Gao (Gypsum Fibrosum) and Zhi Mu (Anemarrhenae Rhizoma). If the coating is yellow with a reddish tint, it indicates heat in the Small Intestine and Bladder; use Shan Zhi (Gardeniae Fructus). If the tongue body is red with a white coating, it indicates Lung heat; use Huang Qin (Scutellariae Radix) and Su Ye (Perillae Folium). If the tongue is black with a reddish tint, it indicates Kidney deficiency with夹杂 (concurrent) pathogenic factors; use Di Huang (Rehmanniae Radix) and Yuan Shen (Scrophulariae Radix), along with Chai Hu (Bupleuri Radix). If the tongue is red with black spots, it indicates extreme Stomach heat; use Yuan Shen (Scrophulariae Radix) and Ge Gen (Puerariae Lobatae Radix). If the tongue is red with white spots, it indicates pathogens in the Heart; use Chai Hu (Bupleuri Radix) and Huang Lian (Coptidis Rhizoma), treating both the Heart and Liver simultaneously. If the tongue is red with large red spots, it indicates Stomach heat with dampness; use Yin Chen Wu Ling San (Artemisiae Scopariae and Five-Ingredient Poria Pill). Since water-dampness must return to the Bladder to dissipate pathogens, Rou Gui (Cinnamomi Cortex) is required to guide the medicine into the Bladder, but only one or two fen should be added, not more. If the coating is white with black spots, it is also Stomach heat; Shi Gao (Gypsum Fibrosum) is appropriate. If the coating is yellow with black, it indicates excess heat in the Liver channel; use Shan Zhi (Gardeniae Fructus) and Chai Hu (Bupleuri Radix). If the coating is white turning yellow, the pathogen is about to enter the interior; use Shan Zhi (Gardeniae Fructus) and Chai Hu (Bupleuri Radix) to resolve it and prevent interior entry. Chai Hu (Bupleuri Radix) is a drug for half-exterior and half-interior conditions and must be used. If the center of the tongue is white and the edges are yellow, the pathogen has entered the Large Intestine; use Wu Ling San (Five-Ingredient Poria Pill) to separate fluids. Once fluids are separated, diarrhea will stop. If the center of the tongue is yellow and the edges are white, the pathogen is inside rather than outside, above rather than below; only add Chai Hu (Bupleuri Radix) and Zhi Ke (Aurantii Fructus), do not lightly use Da Huang (Rhei Radix et Rhizoma). If the root of the tongue is yellow and the middle is smooth and white, it is also Stomach heat with dampness; use Shi Gao (Gypsum Fibrosum) as the sovereign herb, with small amounts of Zhu Ling (Polypori mycetium) and Ze Xie (Alismatis Rhizoma). If the tongue coating is yellow and segmented like slices, the pathogenic heat has deeply entered the Large Intestine; urgently use Da Huang (Rhei Radix et Rhizoma) and Yin Chen (Artemisiae Scopariae Herba); Di Dang Tang (Turdus Decoction) and Shi Zao Tang (Ten Jujube Decoction) should not be used. If purgation has already been delayed, then these must be used. However, one must distinguish between water retention and blood stasis; Shi Zao Tang (Ten Jujube Decoction) drains water, while Di Dang Tang (Turdus Decoction) drains blood. If the tongue surface is red in the middle and looks like it has been eaten by insects, it indicates that water qi has not risen while fire qi attacks; use Huang Lian (Coptidis Rhizoma) and Chai Hu (Bupleuri Radix) to harmonize. If the tongue is red and cracked like the character "Ren" (人), the pathogen has just entered the Heart; use Shi Gao (Gypsum Fibrosum) and Huang Lian (Coptidis Rhizoma). If the root of the tongue is black and the tip is red, there are unresolved pathogens in the Kidney; use Chai Hu (Bupleuri Radix) and Shan Zhi (Gardeniae Fructus). If the root of the tongue is black and the tip is white, Stomach fire is attacking the Kidney; use Shi Gao (Gypsum Fibrosum), Yuan Shen (Scrophulariae Radix), and Zhi Mu (Anemarrhenae Rhizoma). At this point, one need not ask about thirst or diarrhea. If the root of the tongue is black and the tip is yellow, the pathogen is about to enter the Kidney. If there is abdominal pain that refuses pressure, urgently use Da Huang (Rhei Radix et Rhizoma); otherwise, use only Shan Zhi (Gardeniae Fructus) and Chai Hu (Bupleuri Radix). If the tongue is purely red with only the tip black, it indicates Kidney deficiency allowing pathogenic fire to attack; use Yuan Shen (Scrophulariae Radix), possibly up to one liang or more, often used raw; avoid Shi Gao (Gypsum Fibrosum). If the center of the tongue has a red halo and the surrounding edges are purely black, it indicates blazing of the Ministerial Fire and Sovereign Fire; urgently use Da Huang (Rhei Radix et Rhizoma) with approximately one liang of Sheng Di Huang (Rehmanniae Radix); five or six out of ten patients can be saved. If the center is gray and the edges are slightly red, pathogens are knotted in the Large Intestine; purgation leads to cure, failure leads to death. This is due to dryness of Kidney Water; do not directly use Shu Di Huang (Prepared Rehmanniae Radix) to tonify the Kidney. Because the pathogen has not dispersed, tonification will increase distension and urgency; only after the pathogen descends should Sheng Di Huang (Rehmanniae Radix) be used to nourish. However, it should not be used in large amounts. If the tongue is purely gray with only two black rings in the center, the pathogen is also about to enter the Kidney; urgently use Yuan Shen (Scrophulariae Radix) about one liang, with a little Chai Hu (Bupleuri Radix). If the outside is red and the inside is black, it is fire extreme resembling water; urgently use Chai Hu (Bupleuri Radix), Shan Zhi (Gardeniae Fructus), Da Huang (Rhei Radix et Rhizoma), and Zhi Shi (Aurantii Fructus Immaturus). If prickles are also seen, fire hyperactivity is extreme; especially use the aforementioned drugs in larger doses. In summary, cases with black interior and white exterior, or black interior and yellow exterior, are treated as previously described; four or five out of ten can survive. Only when the tongue center is pale black, and the exterior is pale red, pale white, or the interior is pale yellow, which is milder than before, can the previous methods be used; seven or eight out of ten can survive. If the tongue is purely red with several black lines exposed, this is water attacking fire, indicating a Yin syndrome. The tongue coating must be slippery, accompanied by aversion to cold and aversion to water; water swallowed will cause vomiting. If a purely black tongue is seen, it is a sign of certain death; no treatment is necessary. Extreme water resembles fire, and extreme fire resembles water; any tongue showing a band of pure black is untreatable. Understanding the method of inspecting the tongue in Shaoyang disease provides assurance and prevents clinical errors.
Li Zhongzi stated: There are two types of purely black tongues, both indicating fatal conditions. One is fire extreme resembling water, indicating extreme heat; use Da Cheng Qi Tang (Major Order the Qi Decoction). The other is water overcoming fire, indicating extreme cold; the pulse and symptoms must indicate cold; use Fu Zi Li Zhong Tang (Aconite and Ginger Decoction to Regulate the Middle). For a white coating on the tongue, use Xiao Chai Hu Tang (Minor Bupleurum Decoction). For a slippery coating on the tongue, use Xiao Chai Hu Tang without Ban Xia (Pinelliae Rhizoma), adding Ren Shen (Ginseng Radix) and Gua Lou (Trichosanthis Fructus).