大意
诸呕吐酸。皆属于火。（内经）酸者木之味。由火盛制金。不能平木。肝火自甚。故为酸也。（原病式）
内因
有湿热在胃上口。饮食入胃。被湿热郁遏。食不得化。（戴氏。）以致清气不升。浊气不降。清浊相干。气逆于内。
故欲吐复入。是为吞酸。（方氏）
外候
素有湿热。因外感风寒。或食生冷。则内热愈郁。酸味刺心。欲吐不吐。胸中无奈。（入门）或吐出酸水。令上下
齿牙酸涩。不能相对。（发明）是为吐酸。
吞吐各别
吐酸者。吐出酸水。平时津液上升之气。郁滞清道。湿中生热。故从火化。遂作酸味。如谷肉在器。得热则易
酸也。吞酸者。郁滞日久。不能自涌而出。伏于肺胃之间。咯不得上。咽不得下。（指掌）
本热标寒
肌表遇风寒。则湿热愈郁。而酸味入心。肌肤得温暧。则腠理开发。或得香热汤丸。则津液流通。郁热得行。
亦可暂解。盖标寒而本热也。河间言热者。言其本也。东垣言寒者。言其标也。（指掌）
酸分寒热
大凡积滞中焦。久郁成熟。则本从火化。因而作酸者。酸之热也。若客寒犯胃。顷刻成酸。本无郁热。因寒所
化者。酸之寒也。（汇补）
脉法
弦滑为痰滞于内。浮紧为寒束于外。沉迟为中气寒。洪数为火气盛。（医鉴）
治法
初因标寒。宜暂与辛温反佐以开发之。久成郁热。宜以寒凉清解。或分利之。结散热去。则气自通和。酸亦
自已也。（入门）
气实宜疏
吞酸为中气不舒。痰涎郁滞。须先用开发疏畅之品。不宜食粘滑油腻。令气不宣畅。宜入清虚淡蔬。使气
道通利也。（丹溪）
酸久成噎
吞酸。小疾也。然可暂不可久。久而不愈。为膈噎反胃之渐也。若脉两关俱弦者。尤宜慎防。以木来凌土故耳。
（汇补）
用药
主以二陈汤。加吴萸、黄连。顺其性而抑之。佐以山栀、苍术、茯苓。以行湿热。如食不化。平胃散加香附、神曲、
枳实等。如朝食甘美。至晚心腹刺酸吐出者。此血虚火盛。宜加归、芎。若劳役过度。及病后气虚。食入吞酸。
稍顷乃止。此胃弱难化。宜加参、术。
【附吐清水】
吐清水者。其因有五。身受寒气。口食生冷而作者。胃寒也。食少而吐清水者。火虚也。食后而吐清水者。宿
食也。胸膈间辘辘有声者。痰饮也。心腹间时时作痛者。虫也。宜辨而治之。（汇补。）
吞酸选方
茱连丸 治吞酸吐水。更兼胸胁病者。每服二十丸。妙。
黄连（一两） 黄芩 陈皮 吴茱萸（各五钱） 苍术（七钱） 神曲糊丸。白汤服。
二陈汤（方见痰症） 六君子汤（方见中风） 平胃散（方见暑症） 越鞠丸（方见气症）
[General Principle]
Various types of vomiting and acid regurgitation generally belong to Fire pathogen. (From *Neijing*) The sour taste is the flavor of Wood. When Fire is excessive and controls Metal, Metal fails to restrain Wood, causing Liver Fire to become hyperactive, thus producing sourness. (From *Yuanbing Shi*)
[Internal Causes]
If damp-heat exists at the upper orifice of the Stomach, food entering the Stomach is constrained by damp-heat and cannot be digested. (View of Dai) This leads to the failure of Clear Qi to ascend and Turbid Qi to descend; Clear and Turbid Qi interfere with each other, causing Qi rebellion internally.
Therefore, one feels the urge to vomit but swallows it back down; this is called acid regurgitation (swallowing acid). (View of Fang)
[External Manifestations]
If one has pre-existing damp-heat in the body, and subsequently contracts external Wind-Cold, or consumes raw and cold foods, the internal Heat becomes more constrained. The sour taste pierces the Heart, creating an urge to vomit without success, and a sense of distress in the chest. (From *Rumen*) Or, sour water is vomited out, causing the upper and lower teeth to feel sour and numb, making them unable to close against each other. (From *Faming*) This is called vomiting acid.
[Distinction Between Vomiting and Swallowing Acid]
Vomiting acid refers to expelling sour water. This occurs when the Qi of normal fluids, which usually rises, becomes stagnant in the Upper Jiao pathways. Dampness generates Heat within, transforming according to Fire, thus acquiring a sour taste. Just as grains and meats spoil and turn sour when heated in containers.
Swallowing acid (regurgitation) occurs when stagnation persists for a long time, preventing spontaneous expulsion. It lies latent between the Lungs and Stomach, unable to be coughed up or swallowed down. (From *Zhizhang*)
[Root Heat and Branch Cold]
When the body surface encounters Wind-Cold, damp-heat becomes more constrained, and the sour taste affects the Heart. When the body surface is warmed, the pores open. If aromatic and hot soups or pills are taken, fluid circulation improves, and constrained Heat is released, providing temporary relief. This indicates that while the branch manifestation is Cold, the root nature is Heat. Hejian (Liu Wansu) spoke of "Heat" referring to the root; Dongyuan (Li Gao) spoke of "Cold" referring to the branch manifestation. (From *Zhizhang*)
[Distinguishing Cold and Hot Sourness]
Generally, if stagnation accumulates in the Middle Jiao and remains constrained for a long time, it matures and transforms according to Fire, resulting in sourness due to heat; this is "Hot Sourness." If exogenous Cold invades the Stomach, turning into sourness almost instantly, without prior constrained Heat, but rather transformed by Cold, this is "Cold Sourness." (From *Huibu*)
[Pulse Diagnosis]
A wiry and slippery pulse indicates Phlegm-Stagnation internally. A floating and tight pulse indicates Cold binding externally. A deep and slow pulse indicates Cold in the Middle Qi. A surging and rapid pulse indicates Excess Fire. (From *Yijian*)
[Treatment Methods]
Initially, due to branch Cold, use acrid-warm herbs with counter-assistance to open the exterior. If it becomes constrained Heat over time, use cold-cooling herbs to clear and resolve, or promote diuresis to separate and drain. Once the constraint dissipates and Heat clears, Qi will naturally flow harmoniously, and the sourness will cease spontaneously. (From *Rumen*)
[Excess Qi Requires Dispersion]
Acid regurgitation is caused by the discomfort of Middle Qi and stagnation of Phlegm-Saliva. One must first use herbs that open and unblock. Sticky, smooth, greasy, and oily foods should be avoided to prevent obstruction of Qi dispersion. Light, void, and bland vegetables should be consumed to keep the Qi pathways patent. (View of Danxi)
[Prolonged Acid Regurgitation Leads to Dysphagia]
Acid regurgitation is a minor ailment, but it can be treated temporarily, not neglected long-term. If it persists without cure, it may progress to dysphagia (Ge Ye) or reverse flowing stomach contents (Fan Wei). If both Guan pulses on both sides are wiry, extra caution is required, as this indicates Wood encroaching upon Earth. (From *Huibu*)
[Medication]
The main formula is Erchen Tang (Two-Aged Decoction), added with Evodiae Fructus (Wuzhuyu) and Coptidis Rhizoma (Huanglian), to follow its nature while suppressing it. Auxiliary herbs include Gardeniae Fructus (Shanzhi), Atractodis Rhizoma (Cangzhu), and Poria (Fuling) to move damp-heat. If food is not digested, use Pingwei San (Stomach-Ping Powder) added with Cyperi Rhizoma (Xiangfu), Massae Fermentatae Medicinalis (Shenqu), and Aurantii Fructus Immaturus (Zhishi), etc. If sweet and delicious food eaten in the morning causes stabbing pain in the heart and abdomen with vomiting of sour water in the evening, this is Blood deficiency with Hyperactive Fire; add Angelicae Sinensis Radix (Guizhi/Danggui context implies Danggui here usually, but text says Gui, likely Danggui) and Chuanxiong Rhizome (Chuanxiong). If due to overexertion or post-illness Qi deficiency, where eating leads to acid regurgitation that stops after a short while, this is weak Stomach difficulty in digestion; add Ginseng Radix (Renshen) and Atractodis Macrocephalae Rhizoma (Baizhu).
[Appendix: Vomiting Clear Fluid]
There are five causes for vomiting clear fluid: 1. Caused by body exposure to Cold Qi or consumption of raw/cold food: Stomach Cold. 2. Vomiting clear fluid despite little food intake: Deficiency of Fire (Mingmen Fire Deficiency). 3. Vomiting clear fluid after eating: Retained Food. 4. Rumbling sounds in the chest and diaphragm: Phlegm-Fluids. 5. Intermittent pain in the heart and abdomen: Parasites. These must be differentiated and treated accordingly. (From *Huibu*)
[Selected Formulas for Acid Regurgitation]
Zhuolian Wan (Evodia and Coptis Pill): Treats acid regurgitation and vomiting of water, especially with accompanying chest and hypochondriac symptoms. Take 20 pills per dose; highly effective.
Formula: Coptidis Rhizoma (Huanglian, 1 liang), Scutellariae Radix (Huangqin), Citri Reticulatae Pericarpium (Chenpi), Evodiae Fructus (Wuzhuyu, 5 qian each), Atractodis Rhizoma (Cangzhu, 7 qian). Make pills using Massae Fermentatae Medicinalis paste. Take with warm water.
Erchen Tang (See Phlegm Syndrome section), Liujunzi Tang (See Stroke section), Pingwei San (See Summerheat section), Yueju Wan (See Qi Syndrome section)