嗳气者，即《内经》之所谓噫也，此实脾胃之气滞，起自中焦而出于上焦，故经曰∶上
走心为噫也。据丹溪曰∶嗳气，以胃中有痰有火，愚谓此说未必皆然。盖嗳气多由滞逆，滞
逆多由气不行，气逆不行者，多寒少热，可皆谓之火耶？故凡人之饮食太饱者，多有此证，
及饮食不易消化者，亦有此证。但太饱作嗳者，此系实滞，治宜行气化食；食不消化，时多
虚闷作嗳者，此系胃气虚寒，治宜温补。若痰火作嗳者，亦或有之，但停痰必以胃弱，胃弱
多因无火，此当详辨脉证而酌治之也。
一、治嗳之法，凡胃虚兼滞而作嗳者，宜十味保和汤，或枳壳散。若胃寒气滞作嗳者，
和胃煎。若胃寒生痰，呕恶嗳气者，宜和胃二陈煎。若胃气虚寒，饮食难化，时常虚饱嗳气
者，宜温胃饮，或养中煎、理中汤。若脾肾虚寒，命门不暖，阴邪不降，则寒滞上焦而痞满
嗳气者，理阴煎加减治之。
一、丹溪曰∶嗳气以胃中有痰有火，宜用半夏、南星、香附、软石膏、栀子、或汤或丸
服。按此治必真有火邪者乃可用，否则恐滞于中而嗳愈甚。
理中汤（热一） 温胃饮（新热五） 金水六君煎（新和一） 圣术煎（新热二五） 理阴煎（
新热三） 养中煎（新热四） 和胃二陈煎（新和三） 二陈汤（和一） 和胃饮（新和五） 橘皮
半夏汤（和十三） 枳壳散（和一四六） 平胃散（和十七） 十味保和汤（和一四八） 六君子汤
（补五） 调气平胃散（和十八） 竹叶石膏汤（寒六）
Overtone (belching with a long sound), also referred to as "Yi" in the *Huangdi Neijing* (Yellow Emperor's Inner Canon), is essentially caused by the stagnation of Qi in the Spleen and Stomach. Its pathology originates in the Middle Jiao (Middle Burner) and manifests in the Upper Jiao (Upper Burner). Hence, the classics state: "When [Stomach Qi] ascends to the Heart, it becomes Yi." Zhu Danxi stated that overtone is due to phlegm and fire in the Stomach. I believe this view is not entirely accurate. Overtone is mostly caused by Qi stagnation and rebellion; such stagnation and rebellion are often due to the failure of Qi to move freely. Cases of Qi rebellion and immobility are predominantly cold rather than heat; how can they all be attributed to Fire? Therefore, individuals who overeat often suffer from this condition, as do those whose food is difficult to digest. However, overtone resulting from overeating is due to excess stagnation, which should be treated by promoting Qi movement and aiding digestion. Overtone accompanied by frequent feeling of emptiness and fullness due to indigestion is due to deficiency-cold of Stomach Qi, which should be treated by warming and tonifying. Although overtone caused by phlegm-fire may occasionally occur, retained phlegm must stem from weak Stomach function, and weak Stomach function is often due to a lack of Yang Fire. In such cases, one must carefully differentiate the pulse and symptoms to determine the appropriate treatment.
First, regarding the treatment of overtone: For cases where Stomach deficiency combined with stagnation causes overtone, Shiwu Baohe Tang (Ten-Ingredient Harmonizing the Interior Decoction) or Zhike San (Bitter Orange Powder) are suitable. For cases caused by Cold-stagnation in the Stomach, Hewei Jian (Harmonize the Stomach Decoction) is indicated. For cases involving Cold-induced Phlegm in the Stomach, accompanied by vomiting, nausea, and overtone, Hewei Erchen Jian (Harmonize the Stomach Two-Chen Decoction) is suitable. For cases of Stomach Qi deficiency-cold, where food is difficult to transform, leading to frequent false fullness and overtone, Wenwei Yin (Warm the Stomach Drink), Yangzhong Jian (Nourish the Center Decoction), or Lizhong Tang (Regulate the Middle Decoction) are appropriate. For cases of Spleen-Kidney deficiency-cold, where the Mingmen (Gate of Life) fails to warm, causing Yin-Cold pathogens to fail to descend, resulting in Cold-stagnation in the Upper Jiao manifesting as stuffiness, fullness, and overtone, Liyin Jian (Nourish the Yin Decoction) with modifications should be used.
Second, Zhu Danxi stated: "Overtone is due to phlegm and fire in the Stomach; Banxia (Pinellia Rhizome), Nanxing (Arisaema Rhizome), Xiangfu (Cyperus Rhizome), Ruan Shigao (Soft Gypsum), and Zhizi (Gardenia Fruit) should be used, administered as a decoction or pill." According to my analysis, this method is only applicable when there is truly a Fire pathogen; otherwise, it may cause further stagnation in the Middle Jiao, exacerbating the overtone.
Lizhong Tang (Regulate the Middle Decoction) [Ref: Heat 1] · Wenwei Yin (Warm the Stomach Drink) [Ref: New Heat 5] · Jinshui Liu Jun Jian (Metal-Water Six-Gentlemen Decoction) [Ref: New Harmony 1] · Shengzhu Jian (Sage Atractylodes Decoction) [Ref: New Heat 25] · Liyin Jian (Nourish the Yin Decoction) [Ref: New Heat 3] · Yangzhong Jian (Nourish the Center Decoction) [Ref: New Heat 4] · Hewei Erchen Jian (Harmonize the Stomach Two-Chen Decoction) [Ref: New Harmony 3] · Erchen Tang (Two-Chen Decoction) [Ref: Harmony 1] · Hewei Yin (Harmonize the Stomach Drink) [Ref: New Harmony 5] · Jupi Banxia Tang (Tangerine Peel and Pinellia Decoction) [Ref: Harmony 13] · Zhike San (Bitter Orange Powder) [Ref: Harmony 146] · Pingwei San (Level the Stomach Powder) [Ref: Harmony 17] · Shiwu Baohe Tang (Ten-Ingredient Harmonizing the Interior Decoction) [Ref: Harmony 148] · Liu Junzi Tang (Six-Gentlemen Decoction) [Ref: Tonify 5] · Tiaoqi Pingwei San (Regulate Qi Level the Stomach Powder) [Ref: Harmony 18] · Zhuye Shigao Tang (Bamboo Leaf and Gypsum Decoction) [Ref: Cold 6]