脾开窍于口。胃筋脉夹口，胃经血气少，两吻多纹画。大阳脉夹口，交人中。
口苦，心热，黄连、生地、麦冬、丹皮必用。胆热则胆汁上溢亦苦，柴胡、
龙胆草、生甘草、枣仁、茯神、生地。口淡，胃热，石斛、石膏、竹叶、青黛、湿盛
加白术、半夏、茯芩。又大泻后多有口淡者，不可作热治。口甘，脾热，白芍、
山栀、兰草、花粉、黄连。口咸，肾热，六味汤（见虚损）加玄参、知、柏。口酸，肝热，
柴胡、黄连、胆草，逍遥散、越鞠丸。（并见郁。）口辛，肺热，桔梗、山栀、黄芩、桑
皮、二冬、沙参。
口常流涎，脾胃热，津溢也，清胃散。（见齿。）亦有脾虚不摄者，六君子（见气）加益
智妙。亦有肾热者，六味丸（见虚损）加知、柏。
口干涩，火盛津虚，大忌五苓、星、半。五味为君，加二冬、白芍、生甘草、
人参、乌梅。又用黄芩、葛根、（生津）防风、薄荷、（二味 风。按风，即热也。）栝蒌。
（去痰不用星、半而用此，取润恶燥也。）又生津方神效。
口疮，热与痰上盛也。口舌状如无皮，曰口疮；糜烂，曰口糜。实热者可
用寒凉，金花丸、凉膈散、（见发热。）升麻饮之类。西瓜浆最妙，冬月西瓜皮烧
灰，噙。黄连散去热涎。亦有虚热者，脾胃气虚下陷，郁而成火，上炎所致，补中
益气汤（见气）。加竹叶、花粉。若下焦虚寒，逼其无根之火上炎者，八味丸引火归元，
外用生附子末，唾调涂足心。若肾水虚火炎者，六味丸加知、柏。晡热、夜热，
血虚也，八物（并见虚损）加丹皮、五味、麦冬。口破，色红，腮舌肿，干渴，凉膈散（见
发热）、赴筵散；色淡白，不渴，由思烦多醒少睡，虚火所发，滋阴四物汤、柳花散。口
疮连牙根烂痛，玄参散。久不愈，以五倍末擦之，使收敛。鹅口，初生小儿满口生
白屑也，心脾热所致。先用绵蘸水洗去，后用冰硼散吹之。内服凉膈散。口疳，多
食肥甘，积热所致，用口疳药吹之。
口苦无皮，中气虚热，清热补气汤。
口臭，竹叶石膏汤（见烦躁）加减、甘露饮。（胃火之臭必秽浊，若臭而馊腐，则
食停不化之臭，当
辨。）口腥臭，肺热也，桑白皮、地骨皮、黄芩、知母、五味子、麦门冬、桔梗。
悬痈，生上 ，发紫泡者是。银针挑破，吹口疳药，碧丹（见咽喉）亦可。口菌，生牙
肉上，隆起形如菌，紫黑，或生舌上，俱口疳药吹，或用茄母蒂烧灰，盐拌醋调，
时擦。
脾脏的窍穴开在于口。胃部的筋脉环绕于口，若胃经的气血不足，嘴角两侧会出现较多皱纹。太阳经脉环绕于口，在人中穴处相交。
口苦，属于心火亢盛，必须使用黄连、生地黄、麦冬、牡丹皮。胆热导致胆汁上溢也会引起口苦，可用柴胡、龙胆草、生甘草、酸枣仁、茯神、生地黄治疗。口淡无味，属于胃热，可用石斛、石膏、竹叶、青黛；若湿气盛，加白术、半夏、茯苓。另外，在大泻之后出现口淡的情况，不可当作热证治疗。口甜，属于脾热，可用白芍、山栀、兰草、天花粉、黄连。口咸，属于肾热，用六味汤（见虚损篇）加玄参、知母、黄柏。口酸，属于肝热，用柴胡、黄连、龙胆草，或逍遥散、越鞠丸。（均见于郁证篇）。口辛（辛辣感），属于肺热，可用桔梗、山栀、黄芩、桑白皮、天冬和麦冬（二冬）、沙参。
口中常流涎水，是脾胃有热，津液外溢所致，用清胃散。（见齿病篇）。也有因脾气虚弱不能固摄津液的，用六君子汤（见气虚篇）加益智仁。也有因肾热的，用六味丸（见虚损篇）加知母、黄柏。
口干且涩，是火热旺盛而津液亏虚，绝对禁忌使用五苓散、天南星、半夏。以五味子为君药，加天冬、麦冬、白芍、生甘草、人参、乌梅。又方：用黄芩、葛根（生津）、防风、薄荷（这两味药祛风，按：风即指热邪）、栝蒌（去痰不用天南星、半夏而用此药，是取其润燥恶燥的特性）。此生津方效果神效。
口疮，是热邪与痰浊上盛所致。口舌表面状如没有皮肤覆盖，称为口疮；糜烂溃破，称为口糜。实热证可以使用寒凉药物，如金花丸、凉膈散（见发热篇）、升麻饮之类。西瓜汁最为妙用，冬季可用西瓜皮烧成灰，含在口中。黄连散去热除涎。也有虚热证，是因脾胃气虚下陷，郁结而成火，向上炎蒸所致，用补中益气汤（见气虚篇），加竹叶、天花粉。若是下焦虚寒，逼迫无根之火上浮上炎的，用八味丸引火归元，外用生附子末，用唾液调和涂擦足心。若是肾水亏虚导致虚火上炎的，用六味丸加知母、黄柏。傍晚发热、夜间发热，属于血虚，用八物汤（并见虚损篇）加牡丹皮、五味子、麦冬。口腔破损，颜色红，腮部和舌头肿胀，口干渴，用凉膈散（见发热篇）、赴筵散；颜色淡白，不口渴，是由思虑烦扰多、醒着少睡导致的虚火发作，用滋阴四物汤、柳花散。口疮连及牙根腐烂疼痛，用玄参散。久治不愈的，用五倍子末擦患处，使其收敛。鹅口疮，是初生婴儿满口生出白色屑状物，由心脾热所致。先用棉蘸水清洗去除，后用冰硼散吹入。内服凉膈散。口疳，多因过食肥甘厚味，积热所致，用口疳药吹入患处。
口臭，用竹叶石膏汤（见烦躁篇）加减，或甘露饮。（胃火引起的口臭必定秽浊，若臭而带馊腐味，则是食物停滞不化的臭味，应当辨别清楚）。口腥臭，是肺热，可用桑白皮、地骨皮、黄芩、知母、五味子、麦门冬、桔梗。
悬痈，生于上腭，发出紫泡的是。用银针挑破，吹入口疳药，碧丹（见咽喉篇）也可用。口菌，生在牙龈肉上，隆起形状像蘑菇，紫色黑色，或者生在舌头上，都用口疳药吹入，或者用茄子蒂烧成灰，拌盐醋调和，时常擦拭。
The Spleen opens into the mouth. The sinews and vessels of the Stomach flank the mouth; when the Qi and Blood of the Stomach Meridian are deficient, many wrinkles appear at the corners of the mouth. The Taiyang (Greater Yang) meridian flanks the mouth and intersects at the Renzhong point (GV26).
Bitter taste in the mouth indicates Heart Heat; Huanglian (Coptidis Rhizoma), Shengdihuang (Rehmanniae Radix Recens), Maidong (Ophiopogonis Tuber), and Mudanpi (Moutan Cortex) are essential. Bile Heat causing bile to overflow upward also results in bitterness; Chaihu (Bupleuri Radix), Longdancao (Gentianae Radix), Sheng Gancao (Glycyrrhizae Radix et Rhizoma), Zaoren (Ziziphi Spinosae Semen), Fushen (Poria cum Pararadicis), and Shengdihuang (Rehmanniae Radix Recens) may be used. A bland taste in the mouth indicates Stomach Heat; Shihu (Dendrobii Caulis), Shigao (Gypsum Fibrosum), Zhuye (Bambusae Folium), Qingdai (Indigo Naturalis) should be used; if Dampness is prevalent, add Baizhu (Atractylodis Macrocephalae Rhizoma), Banxia (Pinelliae Rhizoma), and Fuling (Poria). Furthermore, after severe purging, a bland taste often occurs and should not be treated as Heat. Sweet taste in the mouth indicates Spleen Heat; Baishao (Paeoniae Radix Alba), Shanzhi (Gardeniae Fructus), Lanco (Gratiatis Herba), Huafen (Trichosanthis Radix), and Huanglian (Coptidis Rhizoma) are indicated. Salty taste in the mouth indicates Kidney Heat; Liuwei Wan (Six-Ingredient Rehmannia Pill) (see Deficiency Damage) with Xuanshen (Scrophulariae Radix), Zhimu (Anemarrhenae Rhizoma), and Baipi (Phellodendri Cortex) should be used. Sour taste in the mouth indicates Liver Heat; Chaihu (Bupleuri Radix), Huanglian (Coptidis Rhizoma), Dancao (Gentianae Radix), Xiaoyao San (Free and Easy Wanderer Powder), or Yueju Wan (Revive the Depressed Pill) may be used (both see Depression Syndrome). Pungent/spicy taste in the mouth indicates Lung Heat; Jiegeng (Platycodonis Radix), Shanzhi (Gardeniae Fructus), Huangqin (Scutellariae Radix), Sangbai (Mori Cortex), Er Dong (Tian Dong and Mai Dong), and Shashen (Glehniae Radix) are appropriate.
Constant salivation from the mouth indicates Heat in the Spleen and Stomach causing fluids to overflow; Qingwei San (Clear the Stomach Powder) is used (see Dental Diseases). There are also cases due to Spleen Qi deficiency failing to control fluids, treated with Liujunzi Tang (Six Gentlemen Decoction) (see Qi Deficiency) plus Yizhi Ren (Alpiniae Oxyphyllae Fructus). There are also cases due to Kidney Heat, treated with Liuwei Wan (Six-Ingredient Rehmannia Pill) (see Deficiency Damage) plus Zhimu (Anemarrhenae Rhizoma) and Baipi (Phellodendri Cortex).
Dryness and astringency in the mouth indicate excessive Fire and deficient fluids; Wuling San (Five-Ingredient Powder with Poria), Tian Nan Xing (Arisaematis Rhizoma), and Banxia (Pinelliae Rhizoma) are strictly contraindicated. Use Wuweizi (Schisandrae Fructus) as the sovereign herb, adding Tian Dong (Asparagi Tuber), Mai Dong (Ophiopogonis Tuber), Baishao (Paeoniae Radix Alba), Sheng Gancao (Glycyrrhizae Radix et Rhizoma), Renshen (Ginseng Radix et Rhizoma), and Wumei (Mume Fructus). Another formula uses Huangqin (Scutellariae Radix), Gegen (Puerariae Lobatae Radix) (to generate fluids), Fangfeng (Saposhnikoviae Radix), Bohe (Menthae Haplocalycis Herba) (these two disperse Wind; note: Wind here refers to Heat), and Gualou (Trichosanthis Fructus) (to resolve phlegm; using this instead of Tian Nan Xing and Banxia takes advantage of its moistening nature to counteract dryness). This fluid-generating formula is extremely effective.
Mouth ulcers result from excess Heat and Phlegm rising. When the oral mucosa appears denuded, it is called Mouth Ulcer (Kou Chuang); when eroded and ulcerated, it is called Mouth Miasma (Kou Mi). Excess Heat can be treated with cold-cooling agents such as Jinhua Wan (Golden Flower Pill), Liangge San (Cool the Diaphragm Powder) (see Fever), or Shengma Yin (Ephedra Decoction). Watermelon juice is excellent; in winter, watermelon rind burned to ash can be held in the mouth. Huanglian San (Coptis Powder) clears heat and removes saliva. There are also Deficient Heat cases caused by Spleen and Stomach Qi deficiency sinking, leading to depression transforming into Fire that flares upward; these are treated with Buzhong Yiqi Tang (Tonify the Middle and Augment the Qi Decoction) (see Qi Deficiency) with Zhuye (Bambusae Folium) and Huafen (Trichosanthis Radix). If Lower Jiao Deficient Cold forces rootless Fire to flare upward, use Bawei Wan (Eight-Ingredient Pill) to guide Fire back to its source, and externally apply raw Fuzi (Aconiti Lateralis Radix Preparata) powder mixed with saliva to the soles of the feet. If Kidney Water deficiency causes Deficient Fire to flare, use Liuwei Wan (Six-Ingredient Rehmannia Pill) plus Zhimu (Anemarrhenae Rhizoma) and Baipi (Phellodendri Cortex). Afternoon fever and night fever indicate Blood deficiency; Bayi Tang (Eight Substances Decoction) (see Deficiency Damage) with Mudanpi (Moutan Cortex), Wuweizi (Schisandrae Fructus), and Maidong (Ophiopogonis Tuber) is used. Broken mouth with red color, swollen cheeks and tongue, and dry thirst are treated with Liangge San (Cool the Diaphragm Powder) (see Fever) or Fuyan San (Banquet Powder); pale white color without thirst, caused by excessive worry and insufficient sleep leading to Deficient Fire, is treated with Ziyin Siwu Tang (Nourish Yin Four Substances Decoction) or Liuhua San (Willow Flower Powder). Mouth ulcers extending to the gums with rotting pain are treated with Xuanshen San (Scrophularia Powder). For chronic non-healing cases, apply Wubeizi (Galla Chinensis) powder to promote astringency. Goose-mouth thrush, characterized by white debris covering the mouths of newborns, is caused by Heart and Spleen Heat. First wash away with cotton dipped in water, then blow Bingpeng San (Ice and Borax Powder) inside. Internally administer Liangge San (Cool the Diaphragm Powder). Oral kan (mouth gangrene), caused by excessive consumption of rich and sweet foods leading to accumulated Heat, is treated by blowing oral kan medicine into the lesion.
Bitter taste with denuded mucosa indicates Middle Qi Deficient Heat; Qingre Buqi Tang (Clear Heat and Tonify Qi Decoction) is used.
Bad breath is treated with modified Zhuye Shigao Tang (Bamboo Leaf and Gypsum Decoction) (see Restlessness) or Ganlu Yin (Sweet Dew Drink). (Odor from Stomach Fire must be foul and turbid; if it smells sour and putrid, it is odor from food stagnation and indigestion, which must be differentiated.) Fishy-bad breath indicates Lung Heat; Sangbaipi (Mori Cortex), Digupi (Lycii Cortex), Huangqin (Scutellariae Radix), Zhimu (Anemarrhenae Rhizoma), Wuweizi (Schisandrae Fructus), Menmendong (Asparagi Tuber), and Jiegeng (Platycodonis Radix) are used.
Xuan Yong (Hanging Abscess), appearing on the soft palate with purple blisters, is punctured with a silver needle, and oral kan medicine is blown in; Bidan (Green Cinnabar Pill) (see Throat Diseases) may also be used. Kou Jun (Mouth Mushroom), growing on the gingiva with a mushroom-like protrusion, purple-black in color, or growing on the tongue, is treated by blowing oral kan medicine, or by burning eggplant stalks to ash, mixing with salt and vinegar, and applying frequently.