薛立斋曰∶吐酸吞酸，大略不同，吐酸者湿中生热，吞酸者虚热内郁，皆属脾胃虚寒，
中传末证。故《内经》以为火者，指其病形而言也，东垣以为胃寒者，指其病本而言也。凡
患此者，先当辨其吞吐而治，以固本元为主，若服寒凉，复伤胃气则实实虚虚者矣。更审其脾气虚而
饮食不能输化，浊气不能下降者，须用六君子汤补养脾胃为主，少佐越鞠丸以清中。故东垣
先生云∶邪热不杀谷。若误认为实热，而妄用寒凉，必变败证。
二陈汤（和一） 平胃散（和十七） 六君子汤（补五） 温胃饮（新热五） 和胃饮（新和五）
加减二陈汤（和二） 圣术煎（新热二五） 理中汤（热一） 理阴煎（新热三） 二术二陈汤（
和四） 橘皮汤（和十一） 越鞠丸（和一五四） 藿香安胃散（热七一）
曲术丸（和百十 宿食） 沉香降气散（和四十 气滞） 半夏丁香丸（和百三十 寒滞）
茱连丸（寒一五三 湿热） 安脾散（热六七 胃寒） 丁香茯苓汤（热六三 温胃行滞） 倍术
丸（热百四 饮）
反胃一证，本属火虚，盖食入于胃，使果胃暖脾强，则食无不化，何至复出？今诸家之
论，有谓其有痰者，有谓其有热者，不知痰饮之留，正因胃虚而完谷复出，岂犹有热？观王
太仆曰∶内格呕逆，食不得入，是有火也；病呕而吐，食入反出，是无火也。此一言者，诚
尽之矣。然无火之由，则犹有上中下三焦之辨，又当察也。若寒在上焦，则多为恶心，或泛
泛欲吐者，此胃脘之阳虚也。若寒在中焦，则食入不化，每食至中脘，或少顷，或半日复出
者，此胃中之阳虚也。若寒在下焦，则朝食暮吐，或暮食朝吐，乃以食入幽门，丙火不能传
化，故久而复出，此命门之阳虚也。故凡治此者，使不知病本所在，混行猜摸，而妄祈奏效
，所以难也。
薛立斋说：吐酸和吞酸，大致上是不同的。吐酸是由于湿中生热，吞酸则是虚热内郁，两者都属于脾胃虚寒，是疾病发展到中后期的表现。所以《内经》认为这是“火”证，是指其外在的病状而言；李东垣认为这是胃寒，是指其疾病的根本而言。凡是患此病的人，首先应当辨别是吐还是吞来进行治疗，以固护本元为主，如果服用寒凉药物，再次损伤胃气，就会造成虚实误治（实证更实，虚证更虚）。再审视如果是脾气虚弱，导致饮食无法运化输布，浊气不能下降的情况，必须使用六君子汤来补养脾胃为主，稍微佐以越鞠丸来清解中焦郁滞。所以李东垣先生说：“邪热不能腐熟水谷。”如果错误地认为是实热，而胡乱使用寒凉药物，必然会导致病情败坏。
二陈汤（调和类第十七方） 平胃散（调和类第十七方） 六君子汤（补益类第五方） 温胃饮（新编热证类第五方） 和胃饮（新编调和类第五方） 加减二陈汤（调和类第二方） 圣术煎（新编热证类第二十五方） 理中汤（热证类第一方） 理阴煎（新编热证类第三方的变方） 二术二陈汤（调和类第四方） 橘皮汤（调和类第十一方） 越鞠丸（调和类第一、一百五十四方） 藿香安胃散（热证类第七十一方）
曲术丸（调和类第一百十方，针对宿食） 沉香降气散（调和类第四十方，针对气滞） 半夏丁香丸（调和类第一百三十方，针对寒滞） 茱连丸（寒证类第一五三方，针对湿热） 安脾散（热证类第六七方，针对胃寒） 丁香茯苓汤（热证类第六十三方，温胃行滞） 倍术丸（热证类第一百四十六方，针对饮邪）
反胃这一病症，本质上属于火虚。因为食物进入胃中，如果确实胃暖脾强，那么食物没有不消化的，怎么会又吐出来呢？现在各家论述，有的说是因为有痰，有的说是因为有热，却不知道痰饮停留，正是因为胃虚导致完谷复出，哪里还有热呢？看王太仆（王冰）说：“内格呕逆，食不得入，是有火也；病呕而吐，食入反出，是无火也。”这句话，确实把道理讲尽了。然而无火的原因，仍然有上、中、下三焦的区分，又应当仔细考察。如果寒邪在上焦，则多为恶心，或者泛泛欲吐，这是胃脘的阳气虚。如果寒邪在中焦，则食入不化，每次进食到中脘穴附近，或稍后片刻，或半天后又吐出，这是胃中的阳气虚。如果寒邪在下焦，则早晨吃晚上吐，或者晚上吃早晨吐，这是因为食物进入幽门，命门之火（丙火）不能传化，所以时间久了又吐出来，这是命门的阳气虚。所以凡是治疗此病的人，如果不了解病的根本所在，胡乱猜测摸索，而妄想求得疗效，所以很难成功。
Xue Lizhai stated: Vomiting acid and swallowing acid are generally different. Vomiting acid arises from heat generated within dampness, while swallowing acid results from internal stagnation of deficient heat; both belong to deficiency-cold of the Spleen and Stomach, representing a late-stage manifestation of the disease. Therefore, the *Neijing* (Classic of Internal Medicine) considers it a "Fire" syndrome, referring to its external pathological presentation; Li Dongyuan considers it Stomach Cold, referring to the root cause of the disease. For those suffering from this condition, treatment should first distinguish between vomiting and swallowing, focusing on consolidating the Yuan Qi (Original Qi). If cold-cooling herbs are administered, further damaging the Stomach Qi, it will lead to erroneous treatment where excess becomes more excessive and deficiency becomes more deficient. Furthermore, if one examines that Spleen Qi is deficient, leading to an inability to transport and transform food and drink, and turbid Qi fails to descend, the Six Gentlemen Decoction (Liujunzi Tang) should be used primarily to tonify and nourish the Spleen and Stomach, with a small addition of Yueju Pill (Yueju Wan) to clear middle-jiao stagnation. Thus, Master Li Dongyuan said: "Pathogenic heat cannot digest grains." If mistakenly identified as excess heat and cold-cooling herbs are recklessly used, it will inevitably lead to a deteriorated syndrome.
Erchen Tang (Harmonizing Class, Formula 17), Pingwei San (Harmonizing Class, Formula 17), Liujunzi Tang (Tonifying Class, Formula 5), Wenwei Yin (New Heat Class, Formula 5), Hewei Yin (New Harmonizing Class, Formula 5), Jiajian Erchen Tang (Harmonizing Class, Formula 2), Shengshu Jian (New Heat Class, Formula 25), Lizhong Tang (Heat Class, Formula 1), Linyin Jian (New Heat Class, Formula 3), Eryu Erchen Tang (Harmonizing Class, Formula 4), Jupi Tang (Harmonizing Class, Formula 11), Yueju Wan (Harmonizing Class, Formulas 1 & 154), Huoxiang Anwei San (Heat Class, Formula 71).
Qushu Wan (Harmonizing Class, Formula 110, for retained food), Chenxiang Jiangqi San (Harmonizing Class, Formula 40, for Qi stagnation), Banxia Dingxiang Wan (Harmonizing Class, Formula 130, for cold stagnation), Zhulian Wan (Cold Class, Formula 153, for damp-heat), Anpi San (Heat Class, Formulas 6-7, for Stomach cold), Dingxiang Fuling Tang (Heat Class, Formula 63, warming Stomach and promoting Qi movement), Beishu Wan (Heat Class, Formula 146, for fluid retention).
The syndrome of regurgitation (Fanwei) essentially belongs to Fire deficiency. When food enters the Stomach, if the Stomach is warm and the Spleen is strong, the food will surely be digested; how could it be vomited out? Current theories by various schools suggest it is due to Phlegm or Heat. However, they do not realize that the retention of Phlegm and fluids is precisely because of Stomach deficiency causing undigested food to be regurgitated; how can there still be Heat? As Wang Taipu (Wang Bing) stated: "Internal obstruction with vomiting and reversal, where food cannot enter, indicates the presence of Fire; vomiting and regurgitating after eating, where food comes back out, indicates the absence of Fire." This statement truly exhausts the principle. Nevertheless, the cause of "absence of Fire" still requires differentiation among the Upper, Middle, and Lower Jiao (Triple Burners), which must be carefully observed. If Cold is in the Upper Jiao, it often manifests as nausea or a general desire to vomit, indicating Yang deficiency in the Epigastrium. If Cold is in the Middle Jiao, food enters but is not digested; upon reaching the Zhongwan point, shortly after or half a day later, it is regurgitated, indicating Yang deficiency within the Stomach. If Cold is in the Lower Jiao, morning food is vomited in the evening, or evening food is vomited in the morning. This occurs because when food enters the幽门 (Pylorus), the Bing Fire (Mingmen Fire) cannot transmit and transform it, so it is eventually regurgitated, indicating Yang deficiency of the Mingmen (Gate of Life). Therefore, in treating this condition, if one does not know the root of the disease, guesses blindly, and recklessly hopes for efficacy, success will be difficult to achieve.