《经》曰∶诸逆冲上，皆属于火；诸呕吐酸皆属于热。又曰∶寒气客于肠胃，厥逆
上出，故痛而呕。呕吐者，阳明之气下行则顺，令逆上行，故作呕吐，有热、有寒、有
食也。然始有因伤乳过满而溢，以致导虚胃气，渐成斯症者有之。凡有声有物，开口而
作者，名曰呕。有物无声者，名曰吐。有声无物者，谓之哕。又有 乳者，乳自流出，
似檐水射出之象。 者，心胸上下气逆郁筑。哕者，膈虚胃寒以致哕，哕作声，无物
可出也，然候不一。如儿初生，有因母有伏痰，得之胎气使然者，有因拭口不净，恶水
流毒所致者，有饮食作乘，又触惊怒，胃气受伤，恶食胃痛而致者。若耳后红纹两颊红
紫，气粗作吐者，此发痘疹之候。如肤削神困，自动不停，不思乳食，是胃气虚弱，不
能消纳，此为虚吐。如面青唇白，清涎夹乳，喜热恶寒，四肢凄清，此为冷吐。至如
胃有实火，则吐黄水而味苦，胸前烦躁。若乘厥阴而入肝，则为酸为逆，多怒烦啼，此
为热吐。如咳嗽气急、吐清水而膈闷者，是胃有寒邪，中有顽痰已而成热，此为痰吐。
若饮食不化，酸臭上逆，恶食不渴，胃痛潮热者，是伤食、伤寒也。若黄痰稠涎，作
噫、作呕者，皆炎之征也。如面白手焦，或面有白斑点子，唇红或紫，昏困时吐不醒人
事，胃口时痛时止而呕清水者，虫吐也。如唇黑多哭，夹痰吐乳者，是伤脾也。如身上
发热，咳嗽痰鸣，夜间烦躁，鼻青吐乳者，是客风伤肺也。如早晚发热，山根青色，吐
而不睡者，是惊吐也。治吐之法，当辩新久寒热，如初吐当导利以顺气下行。吐久者，
须防胃虚生风，故治吐症，贵扶胃气为要。如吐不已，可微止之，元使太泄胃气，惟有
风疾及夹痰吐者，不可遽止，否则，风无定处。更入外风，痰热相生，必成惊候。其余
诸吐初起，及微视乳，盒饭调治。如 不已即成吐，吐之不己即成呕，呕之不已即成
HT，HT 之不已即成哕。至此胃气大衰，精神渐脱矣。若至呕吐不已，日渐沉困，囟陷囟
肿，青筋大露者，非频吐不食，昏沉语塞，喘急上热，常呕腥臭者，皆死。又有时时吐
唾者，多因肾气衰冷，不能藏蓄津滋，润 心肺，久必渐为黄瘦，宜煎地黄料浩饮之。
又有胃气衰冷，不能营运津液所致者，此宜温补胃气。又有心脾蕴热，《经》曰“舌纵
涎下，皆属于热”者，宜清理之。属肾、属胃、属脾，为虚、为寒、为热，常以色脉辩之。
《黄帝内经》说：各种气逆冲上的病证，都属于火；各种呕吐酸水的症状，都属于热。又说：寒气侵入肠胃，导致气机厥逆向上冲出，所以出现疼痛并伴随呕吐。呕吐这一病症，是因为阳明胃气本应下行却反而上逆，从而引发呕吐，其病因可分为热、寒、食积三类。然而，也有因为哺乳过量导致乳汁溢出，进而损伤虚弱的胃气，逐渐形成这种病症的情况。
凡是既有声音又有实物吐出，张口即发的，称为“呕”。只有实物吐出而没有声音的，称为“吐”。只有发出声音而没有实物吐出的，称为“哕”（呃逆）。还有“溢乳”，是指乳汁自然流出，像屋檐滴水射出的样子。“噎”（此处指气逆郁结），是指心胸上下气机逆乱郁结阻塞。“哕”则是由于膈部虚弱、胃寒导致的呃逆，虽然发出声音，但没有实物可出，但其表现并不单一。
例如婴儿刚出生时，有的因为母亲体内有伏痰，受胎气影响而得此症；有的因为清理口腔不干净，恶水流毒所致；有的因饮食失调，又受到惊吓或愤怒刺激，导致胃气受伤，厌恶食物、胃痛而引发呕吐。如果耳后出现红纹、两颊红紫，呼吸粗重并伴有呕吐，这是痘疹即将发出的征兆。如果身体消瘦、精神困倦，动作不由自主不停歇，不思吃奶进食，这是胃气虚弱，不能消化接纳食物，属于虚性呕吐。如果面色青白、嘴唇苍白，清稀涎沫中夹杂乳汁，喜欢温暖、厌恶寒冷，四肢冰凉，这属于冷性呕吐。至于胃中有实火，则呕吐黄水且味道苦涩，胸部烦躁不安。若病邪乘厥阴经传入肝脏，则表现为酸味和逆气，容易发怒、烦躁啼哭，这属于热性呕吐。如果咳嗽气急、呕吐清水且胸膈闷堵，这是胃有寒邪，体内有顽固痰湿已化热，属于痰性呕吐。如果饮食不消化，酸臭之气上逆，厌恶食物且不口渴，胃痛且有潮热，这是伤食和伤寒。如果黄痰稠涎，打嗝、呕吐，都是火热炎症的征象。如果面色苍白、手部焦枯，或者面部有白斑点，嘴唇红或紫，昏沉困倦时常呕吐至人事不知，胃口时而疼痛时而停止并呕吐清水，这是虫积引起的呕吐。如果嘴唇发黑、多哭闹，夹带痰液呕吐乳汁，这是脾脏受损。如果身上发热、咳嗽痰鸣、夜间烦躁、鼻头青色并呕吐乳汁，这是外感风邪伤及肺脏。如果早晚发热、山根（鼻梁根部）青色、呕吐后无法安睡，这是惊悸引起的呕吐。
治疗呕吐的方法，应当辨别病程的新久以及寒热性质。如初起呕吐，应当通过疏导利下的方法使气机下行顺畅。呕吐日久者，必须防止胃虚生风，因此治疗呕吐症，以扶持胃气为关键。如果呕吐不止，可以轻微止吐，但不要过度使用泻法以免严重耗损胃气。只有风疾及夹痰引起的呕吐，不可立即强行止吐，否则风邪没有固定去处，更易引入外风，痰热相生，必然形成惊风证候。其余各类呕吐初起，以及轻微哺乳不当引起的，应当调理治疗。如果溢乳不止就会变成呕吐，呕吐不止就会变成干呕，干呕不止就会变成呃逆，呃逆不止就会导致胃气大衰，精神逐渐脱失。如果发展到呕吐不止，日渐沉重困顿，囟门凹陷或肿胀，青筋暴露，或者频繁呕吐不进食，昏沉不语，喘促气急上部发热，经常呕吐腥臭之物，这些都是死症。另外，有时时时吐唾沫，多因肾气衰冷，不能藏蓄津液滋润心肺，久而久之会逐渐变成黄瘦，适宜煎煮地黄料浩饮服用。又有因胃气衰冷，不能运化津液所致的，这种情况适宜温补胃气。还有心脾蕴热的，《内经》说：“舌体纵缓流涎，都属于热”，这种情况适宜清热清理。无论是属肾、属胃还是属脾，是虚证、寒证还是热证，通常通过观察面色和脉象来辨别。
The *Classic* (Huangdi Neijing) states: All rebellious qi rushing upward belongs to Fire; all vomiting and acid regurgitation belong to Heat. It also states: When Cold pathogen lodges in the Stomach and Intestines, causing Jue-Ni (rebellious counterflow) to rush upward, pain and vomiting occur. Vomiting occurs because the Qi of the Yangming Stomach, which should descend smoothly, instead rebels and ascends. The etiologies include Heat, Cold, and Food Retention. However, there are cases where excessive feeding leads to overflow, further damaging the deficient Stomach Qi, gradually resulting in this condition.
That which involves both sound and matter, occurring upon opening the mouth, is termed "Ou" (Vomit). That which involves matter but no sound is termed "Tu" (Regurgitate). That which involves sound but no matter is termed "Yueh" (Hiccups/Retching). There is also "Yi Ru" (Spilling Milk), where milk flows out naturally, resembling water shooting from an eaves trough. "Ye" (Choking/Stagnation) refers to rebellious Qi stagnating and obstructing the upper and lower chest. "Yueh" results from deficiency in the Diaphragm and Cold in the Stomach; although sound is produced, no matter exits. Its manifestations vary. For instance, in newborns, it may arise from latent Phlegm in the mother transmitted via fetal Qi, or from unclean oral wiping leading to toxic fluids, or from dietary mishaps combined with fright and anger injuring Stomach Qi, causing aversion to food, stomach pain, and vomiting. If red lines appear behind the ears and the cheeks are red-purple, accompanied by coarse breathing and vomiting, this is a sign that smallpox/rashes are about to erupt. If the body is emaciated, spirit is exhausted, movements are involuntary and ceaseless, and there is no desire for milk or food, this is Deficient Vomiting due to weak Stomach Qi unable to digest and accept nourishment. If the face is cyan and lips pale, with clear saliva mixed with milk, preferring warmth and fearing cold, with cold limbs, this is Cold Vomiting. If there is Excess Fire in the Stomach, yellow bitter fluid is vomited, accompanied by chest restlessness. If the pathogen enters the Liver via the Jueyin channel, sourness and rebellion occur, with irritability and frequent crying, constituting Heat Vomiting. If coughing, rapid breathing, vomiting of clear fluid, and chest oppression occur, this is Phlegm Vomiting due to Cold pathogen in the Stomach and stubborn Phlegm transforming into Heat. If undigested food causes sour and foul regurgitation, aversion to food, lack of thirst, stomach pain, and tidal fever, this is Food Injury and Cold Damage. If thick yellow phlegm and saliva cause belching and vomiting, these are signs of inflammatory Heat. If the face is pale, hands are dry/scorched, or white spots appear on the face, lips are red or purple, and the infant becomes comatose after vomiting, with intermittent stomach pain and vomiting of clear fluid, this is Worm Vomiting. If lips are black, crying is frequent, and milk is vomited with phlegm, this indicates Spleen injury. If the body is feverish, coughing with rattling phlegm, night-time restlessness, nasal cyanosis, and milk vomiting occur, this is External Wind injuring the Lung. If fever occurs morning and evening, the Shan Gen (root of the nose) is cyan, and vomiting prevents sleep, this is Fright Vomiting.
The treatment of vomiting must distinguish between new/old onset and Cold/Heat patterns. For initial vomiting, guiding and purging methods should be used to facilitate downward Qi movement. For chronic vomiting, one must guard against Wind generated by Stomach deficiency; thus, supporting Stomach Qi is paramount. If vomiting persists, mild ant-emetics may be used, but excessive purging must be avoided to prevent severe depletion of Stomach Qi. Only in cases of Wind disorders and Phlegm-complexed vomiting should stopping vomiting not be done hastily; otherwise, Wind has no fixed location, external Wind may invade, and Phlegm-Heat may generate, inevitably leading to Convulsive disorders. Other initial vomiting cases and those caused by improper feeding should be regulated and treated. If Yi Ru persists, it becomes Tu; if Tu persists, it becomes dry retching; if dry retching persists, it becomes Yueh. At this stage, Stomach Qi is severely depleted, and Spirit is fading. If vomiting continues, becoming increasingly severe with sunken or swollen fontanelles, exposed blue veins, frequent vomiting without eating, coma with blocked speech, panting with upper heat, or frequent vomiting of foul-smelling fluid, these are death omens. Additionally, constant spitting of saliva is often due to declining and cold Kidney Qi, failing to store fluids to moisten the Heart and Lungs, eventually leading to yellow emaciation; decoctions of Rehmannia (Di Huang) are suitable. Cases due to declining and cold Stomach Qi failing to transport fluids require warming and tonifying Stomach Qi. Cases of Heat accumulation in the Heart and Spleen, as stated in the Classic: "Flaccid tongue with drooling belongs to Heat," require clearing and purging. Whether involving the Kidney, Stomach, or Spleen, and whether Deficient, Cold, or Heat, differentiation is typically made through observation of complexion and pulse.