发汗后水药不得入口为逆若更发汗必吐下不止
汗出阳泄土败胃逆水药不得入口是谓逆治若更发汗阳败土崩太阴吐利之证必将俱作无有止期矣
病患脉数数为热当消谷引食而反吐者此以发汗令阳气微膈气虚脉乃数也数为客热不能消谷以胃中虚冷故吐也
阴阳互根阳虚脱根升浮于上是以脉数数为客热升浮不能消化水谷故作呕吐缘其阳亡而胃中虚冷也
太阳病吐之但太阳病当恶寒今反不恶寒不欲近衣此为吐之内烦也
太阳病伤寒中风表邪外闭营卫不达当见恶寒吐伤胃气里阳上逆外达皮毛故反不恶寒而欲去衣被此为吐之令阳火离根
而内烦故也
太阳病当恶寒发热今身自汗出不恶寒发热关上脉细数者以医吐之过也一二日吐之者腹中饥口不能食三四日吐之者不
喜糜粥欲食冷食朝食暮吐以医吐之所致也此为小逆
吐伤胃阳虚浮无根故关脉细数一二日胃病尚浅吐则伤轻胃中虚馁故饥而胃气上升故不能食三四日胃病颇深吐则伤重
阳火虚浮故不喜糜粥欲食冷食而胃中虚冷不能化谷故朝食暮吐此亦过吐伤胃是谓小逆迟则微阳续复逆气乃下也汗吐下温
针诸逆之中惟吐为轻凡胸腹之内腐败壅塞隔碍真阳郁闷懊 头痛心烦吐之清气通畅即刻轻安最妙之法也即吐之过当中虚
内烦亦无汗下亡阳诸祸一温中气虚烦立止最易治疗故曰小逆也
发汗之后，水和药物都无法入口，这属于逆证；如果再次发汗，必然导致呕吐和腹泻不止。
汗出导致阳气外泄，脾土衰败，胃气上逆，水和药物无法入口，这就叫做“逆”。如果再次发汗，会导致阳气败坏、脾土崩解，太阴病（脾虚寒湿）的呕吐和下利症状必将全部发作，没有停止的时候。
病人脉象数，数脉主热，按理应当能消化食物并感到饥饿想吃东西，却反而呕吐，这是因为发汗导致阳气微弱、胸膈之气虚弱，所以脉象才表现为数。这种数脉是客热（虚浮的热邪），不能消化食物，是因为胃中虚冷，所以发生呕吐。
阴阳互为根本，阳气虚弱则根基脱落，升浮于上，因此脉象数。这种数脉是客热，升浮在外，不能消化水谷，所以发生呕吐，原因在于阳气亡失而胃中虚冷。
太阳病被误用吐法，但太阳病本应恶寒，现在反而不恶寒，不喜欢穿衣，这是误用吐法导致内部烦热的表现。
太阳病（包括伤寒和中风）表邪闭塞在体表，营卫之气不能通达，本应当出现恶寒的症状。误用吐法损伤了胃气，导致里阳上逆，向外达于皮毛，所以反而不恶寒且想要去除衣被，这是误用吐法使阳火脱离根基，从而导致内部烦热。
太阳病本应恶寒发热，现在身体自汗出，不恶寒也不发热，关上脉细数，这是医生误用吐法的过错。发病一二天就误用吐法的，患者腹中感觉饥饿，但嘴里吃不下东西；发病三四天就误用吐法的，不喜欢喝稀粥，想吃冷的食物，早上吃的晚上吐出来，这都是因为医生误用吐法所造成的。这属于“小逆”（较轻的误治）。
吐法损伤了胃阳，使其虚浮无根，所以关脉细数。发病一二天，胃病尚浅，吐法伤害较轻，胃中虚弱空虚，所以感到饥饿，但胃气上逆，所以吃不下东西。发病三四天，胃病较深，吐法伤害较重，阳火虚浮，所以不喜欢喝稀粥，想吃冷的食物，但因为胃中虚冷，不能消化谷物，所以早上吃的晚上吐出来。这也是过度使用吐法损伤了胃气，称为“小逆”，稍后微弱的阳气会重新恢复，逆上的气机才会下行。在汗、吐、下、温针等各种误治导致的逆证中，只有吐法相对较轻。凡是胸腹之内有腐败壅塞、阻碍真阳、郁闷懊恼、头痛心烦的情况，使用吐法使清气通畅，即刻就能轻快安适，这是最好的方法。即使吐法过度导致中气虚弱、内部烦热，也没有汗法、下法导致亡阳那样的祸患，只要温补中气，虚烦就会立刻停止，最容易治疗，所以称为“小逆”。
After sweating, if water and medicine cannot be taken into the mouth, it is considered a *ni* (adverse/rebellious condition); if sweating is induced again, vomiting and diarrhea will inevitably continue without stopping.
Sweating causes the leakage of *Yang Qi* (Vital Energy), the failure of *Earth* (Spleen/Stomach function), and the rebellion of *Stomach Qi* (Stomach Energy), resulting in the inability to ingest water and medicine; this is termed "adverse." If sweating is induced again, *Yang Qi* will fail and *Earth* will collapse, causing the symptoms of *Taiyin Disease* (a syndrome characterized by Spleen deficiency and cold-dampness) such as vomiting and diarrhea to manifest fully, with no end in sight.
If a patient has a rapid pulse (*Shu Mai*), which indicates heat and should theoretically allow for the digestion of food and induce hunger, yet they vomit instead, this is because sweating has caused *Yang Qi* to become weak and *Ge Qi* (Qi at the diaphragm/chest) to become deficient, leading to the rapid pulse. This rapid pulse represents "guest heat" (floating false heat) that cannot digest food, due to cold deficiency in the Stomach, hence the vomiting.
Yin and Yang are mutually rooted. When *Yang Qi* is deficient, its root is lost, causing it to float upward, resulting in a rapid pulse. This rapid pulse is guest heat floating upward, unable to transform water and grain, thus causing vomiting; the root cause is the loss of *Yang Qi* and cold deficiency in the Stomach.
In *Taiyang Disease* (Sun-Yang Disease, an exterior syndrome), if emesis is induced, although Taiyang disease typically presents with aversion to cold, the patient now shows no aversion to cold and dislikes wearing clothes. This is internal irritability (*Nei Fan*) caused by the adverse effect of emesis.
*Taiyang Disease*, whether Cold Damage or Wind Strike, involves exterior pathogenic closure preventing the circulation of *Ying Qi* (Nutritive Energy) and *Wei Qi* (Defensive Energy), typically presenting with aversion to cold. Emesis injures *Stomach Qi*, causing interior *Yang* to rebel upward and reach the skin and hair, resulting in no aversion to cold and a desire to remove clothing/bedding. This is because emesis causes *Yang Fire* to lose its root, leading to internal irritability.
*Taiyang Disease* should present with aversion to cold and fever. Now, the patient has spontaneous sweating, no aversion to cold, no fever, and a fine and rapid pulse at the *Guan* position (middle position on the radial artery). This is the fault of the physician inducing emesis. If emesis is induced on the first or second day, the patient feels hungry in the abdomen but cannot eat; if induced on the third or fourth day, the patient dislikes congee and desires cold food, vomiting what was eaten in the morning by evening. All these are caused by the physician's erroneous use of emesis. This is called "minor adverse" (*Xiao Ni*).
Emesis injures *Stomach Yang*, making it floating and rootless, hence the fine and rapid pulse at the Guan position. On days one or two, the Stomach disease is shallow, and the injury from emesis is light; the Stomach is deficient and empty, causing hunger, but rebellious Stomach Qi prevents eating. On days three or four, the Stomach disease is deep, and the injury from emesis is heavy; *Yang Fire* is floating and deficient, so the patient dislikes congee and desires cold food. However, due to cold deficiency in the Stomach, grain cannot be transformed, leading to morning intake and evening vomiting. This is also "over-emesis injuring the Stomach," termed "minor adverse." Later, the slight *Yang Qi* will recover, and the rebellious Qi will descend. Among adverse conditions caused by sweating, emesis, purging, and warm needle therapy, emesis is the mildest. Wherever there is corruption and obstruction in the chest and abdomen, blocking true *Yang*, causing depression, restlessness, headache, and heart irritability, using emesis to clear the clear Qi provides immediate relief and comfort; this is the best method. Even if excessive emesis leads to middle Qi deficiency and internal irritability, it does not carry the disaster of Yang collapse caused by sweating or purging. Simply warming and tonifying the middle Qi will immediately stop the deficiency irritability; it is easy to treat, hence termed "minor adverse."