中央黄色，入通于脾，开窍于口，藏精于脾，足阳明胃之脉，侠口，下交承浆。（《素问》）侠口属冲任二
脉。（《灵枢》）口属脾胃，大肠脉交口，然毕竟脾经为主。盖五味入口，藏于胃脾，乃运化精液以营养五脏，五
脏之气，皆统于脾。五脏偏盛，皆验于口。胃经气血少，则两吻多纹书。（《嵩崖》）
内因 味入于口，藏精脾胃，运化精液，以养五脏。若五味过偏，则五脏之气亦偏，而诸病生焉。（《大全》）
凡人晨起及食后不漱口，每多口齿腐臭，及生疮菌等患。
外候 肝热则口酸，心热则口苦，脾热则口甘，肺热则口辛，肾热则口咸，胃热则口淡。（《正传》）此脏
气偏胜为病也。亦有谋虑不决，肝移热于胆而口苦者；有脾胃气弱，木乘土位而口酸者；有膀胱移热于小肠，膈
肠不便，上为口糜而生疮溃烂者。（《内经》）有热积心胸之间，脾气凝滞不能运化，浊气熏蒸而口臭者，此脏
气移热而为病也。（《汇补》）
论口疮赤白之异及午前午后痛者微甚之分。口疮虽由脾热所使然，当分赤白二种。白者肺热；赤者心热；赤
白相兼者，心肺俱热，不独脾家病也。（李惺庵）实热者，色多赤；虚热者色多白。午前痛甚者，实火也；午后
痛甚者，虚火也。亦有阴虚火炎，发为口糜，满咽如白饭者，未可概目为肺热也。（岫云）
脉法 脉浮数为实火，浮大为虚火。（《汇补》）浮数有力按之不减为实，浮大而数按
之弱涩为虚，须细辨之为要。
治法 五脏之气皆统于脾，凡七情六欲，五味皆能致病，当因病而求之。（《绳墨》）若服凉剂不愈者，此
中焦元气不足，虚火炎上也，又宜温补。（李惺庵）
用药加减法 肺热口辛，桔梗、山栀、炒芩、桑白皮、天冬、麦冬、沙参。胆热口苦，柴胡、草龙胆、枣仁、
茯神、生地、生甘草。心热口苦，黄连、生地、麦冬、丹皮。肝热口酸，逍遥散。脾虚木乘土位而口酸者，四君
子加白芍、柴胡。脾热口甘，白芍、天花粉、山栀、陈皮、兰草。胃热口淡，青黛、石斛、石膏、竹叶。胃火口
臭，竹叶石膏汤。口燥二冬、五味、白芍、生甘草、人参。肾热口咸，六味加玄参、知母。口糜实热加味逍遥。
虚热补中益气。（《嵩崖》）
膀胱移热，口烂溺涩，导赤散。中上虚寒胃阳浮上者，理中汤。下焦火炎者，八味丸。（《汇补》）
The center corresponds to yellow, its qi connects with the Spleen, opens into the mouth, and stores essence in the Spleen. The Foot-Yangming Stomach Meridian runs alongside the mouth and descends to intersect at Chengjiang (CV24). (From *Suwen*) The area alongside the mouth belongs to the Chong and Ren Mai vessels. (From *Lingshu*) The mouth is governed by the Spleen and Stomach; although the Large Intestine meridian also intersects at the mouth, ultimately the Spleen meridian is primary. This is because the five flavors enter the mouth, are stored in the Stomach and Spleen, and then transformed into refined fluids to nourish the five Zang organs. The qi of the five Zang organs is all regulated by the Spleen. Excesses or deficiencies in the five Zang organs are manifested in the mouth. If the Qi and Blood of the Stomach meridian are insufficient, many wrinkles will appear at the corners of the mouth. (From *Songya*)
Internal causes: Flavors enter the mouth, their essence is stored in the Spleen and Stomach, which transform refined fluids to nourish the five Zang organs. If the five flavors are excessively biased, the qi of the five Zang organs will also become unbalanced, giving rise to various diseases. (From *Daquan*)
Ordinary people who do not rinse their mouths upon waking up in the morning and after meals often suffer from putrid breath, as well as oral ulcers and fungal infections.
External signs: Liver heat causes a sour taste in the mouth; Heart heat causes a bitter taste; Spleen heat causes a sweet taste; Lung heat causes a pungent taste; Kidney heat causes a salty taste; Stomach heat causes a bland taste. (From *Zhengchuan*) These are diseases caused by the excess of Zang organ qi. There are also cases where indecisive deliberation causes Liver heat to transfer to the Gallbladder, resulting in a bitter taste; cases where weak Spleen and Stomach qi allow Wood to overact on Earth, resulting in a sour taste; and cases where bladder heat transfers to the Small Intestine, causing obstruction in the diaphragm and intestines, rising upward to cause oral ulceration and sores. (From *Neijing*) There are cases where heat accumulates between the Heart and Chest, causing Spleen qi to stagnate and fail to transform, leading to bad breath due to turbid qi steaming upward; this is a disease caused by the transfer of heat among Zang organs. (From *Huibu*)
Discussion on the differences between red and white mouth ulcers and the severity of pain before and after noon. Although mouth ulcers are caused by Spleen heat, they should be divided into two types: red and white. White indicates Lung heat; red indicates Heart heat; mixed red and white indicates heat in both the Heart and Lungs, not merely a Spleen disorder. (Li Xing'an) Excess heat tends to be red; deficiency heat tends to be white. Severe pain before noon indicates excess fire; severe pain after noon indicates deficiency fire. There are also cases of Yin deficiency with flaming fire causing oral candidiasis (mouth糜), covering the throat like white rice grains; these cannot be generally classified as Lung heat. (Xiuyun)
Pulse diagnosis: A floating and rapid pulse indicates excess fire; a floating and large pulse indicates deficiency fire. (From *Huibu*) A floating and rapid pulse that remains forceful upon deep pressure indicates excess; a floating, large, and rapid pulse that becomes weak and choppy upon deep pressure indicates deficiency. Careful differentiation is essential.
Treatment principles: The qi of the five Zang organs is regulated by the Spleen. All emotional disturbances (Seven Emotions and Six Desires) and dietary biases can cause disease; treatment should be sought based on the specific cause. (From *Shengmo*) If cooling agents fail to cure, it is due to insufficiency of Yuan Qi in the Middle Jiao with deficiency fire flaring upward; warm tonification is appropriate. (Li Xing'an)
Medication modifications: For Lung heat with pungent taste: Jiegeng (Platycodon Root), Zhizi (Gardenia Fruit), fried Huangqin (Scutellaria Root), Sangbaipi (Mulberry Bark), Tiandong (Asparagus Tuber), Maidong (Ophiopogon Tuber), Shashen (Glehnia Root). For Gallbladder heat with bitter taste: Chaihu (Bupleurum Root), Caolongdan (Gentiana Scabra Root), Zaoren (Ziziphus Seed), Fushen (Poria with Hostwood), Shengdi (Rehmannia Root), Sheng Gancao (Raw Licorice Root). For Heart heat with bitter taste: Huanglian (Coptis Rhizome), Shengdi, Maidong, Danpi (Moutan Cortex). For Liver heat with sour taste: Xiaoyao San (Free and Easy Wanderer Powder). For Spleen deficiency with Wood overacting on Earth causing sour taste: Sijunzi Tang (Four Gentlemen Decoction) plus Baishao (White Peony Root) and Chaihu. For Spleen heat with sweet taste: Baishao, Tianhuafen (Trichosanthes Root), Zhizi, Chenpi (Aged Tangerine Peel), Lanco (Hedyotis Diffusa). For Stomach heat with bland taste: Qingdai (Indigo Naturalis), Shihu (Dendrobium Stem), Shigao (Gypsum Fibrosum), Zhuye (Bamboo Leaf). For Stomach fire with bad breath: Zhuye Shigao Tang (Bamboo Leaf and Gypsum Decoction). For dry mouth: Erdong (Tiandong and Maidong), Wuweizi (Schisandra Berry), Baishao, Sheng Gancao, Renshen (Ginseng Root). For Kidney heat with salty taste: Liuwei Dihuang Wan (Six-Ingredient Rehmannia Pill) plus Xuanshen (Scrophularia Root) and Zhimu (Anemarrhena Rhizome). For excess heat mouth ulcers: Jiawei Xiaoyao San (Modified Free and Easy Wanderer Powder). For deficiency heat mouth ulcers: Buzhong Yiqi Tang (Tonify the Middle and Augment the Qi Decoction). (From *Songya*)
For bladder heat transferring, causing oral sores and painful/difficult urination: Daochi San (Guide Out Redness Powder). For deficiency-cold in the Middle and Upper Jiao with floating Stomach Yang: Lizhong Tang (Regulate the Middle Decoction). For flaming fire in the Lower Jiao: Bawei Wan (Eight-Ingredient Pill). (From *Huibu*)