仲景曰∶病患手足厥冷，脉乍紧者，邪结在胸中，心中满而烦，饥不能食者，病在胸中，当吐
之，宜瓜蒂散。病患手足厥冷，脉乍结，以客气在胸中，心下满而烦，饮食不能入者，病在胸中，
当吐之。
曰∶病如桂枝证，头不痛，项不强，寸脉微浮，胸中痞硬，气上冲咽喉，不得息者，此为胸有
寒也，当吐之，宜瓜蒂散。少阴病，饮食入口则吐，心中温温欲吐，复不能吐，始得之，手足寒，
脉弦迟者，此胸中实，不可下也，当吐之。若膈上有寒饮，干呕者，不可吐也，急温之，宜四逆汤
。按∶此二节，前节言胸有寒者，谓寒邪也，所以当吐；后节言膈上有寒饮，干呕者，谓中寒也，
所以宜温。然则前节之言寒者，言寒邪之实，后节之言寒者，言胃气之虚，均谓之寒，而有虚实之
异。实者宜吐，吐则散也；虚而吐之，则胃气愈虚，病必更甚矣。此等要处，最当详察。
曰∶病胸上诸实，胸中郁郁而痛，不能食，欲使人按之，而反有涎唾，下痢日十余行，其脉反
迟，而寸脉微滑，此可吐之，吐之痢则止。
曰∶太阳病，吐之，但太阳病当恶寒，今反不恶寒，不欲近衣者，此为吐之内烦也。按∶此以
太阳证有不当吐而吐者，必邪热乘虚入胃，故致内烦也。
一、宿食在上脘者，当吐之。
一、凡用吐药，中病即止，不必尽剂也。
一、寸脉弱而无力者，切忌用吐。
张仲景说：如果病人手足冰冷，脉搏突然变得紧涩，这是邪气结聚在胸中，心中感到胀满且烦躁，虽然饥饿却无法进食，病位在于胸中，应当采用涌吐法治疗，适宜使用瓜蒂散。如果病人手足冰冷，脉搏突然变得结滞，这是因为客气（外邪）停留在胸中，胃脘部胀满且烦躁，饮食无法进入，病位在于胸中，应当采用涌吐法治疗。
又说：病症表现类似桂枝汤证（太阳中风表虚证），但头部不痛，颈部不强硬，寸脉微微浮起，胸中感觉痞塞坚硬，有气向上冲撞咽喉，导致呼吸不畅，这是胸中有寒邪所致，应当采用涌吐法治疗，适宜使用瓜蒂散。少阴病（少阴经受邪所致的病证），食物入口即吐出，心中泛泛作恶欲吐却又吐不出来，刚发病时手足寒冷，脉搏弦而迟缓，这是胸中有实邪阻滞，不可使用泻下法，应当采用涌吐法。如果是膈上有寒饮停留，出现干呕症状的，不可使用涌吐法，应当紧急温补阳气，适宜使用四逆汤。
按语：以上两节内容，前一节所说的“胸有寒”，指的是寒邪实证，所以应当涌吐；后一节所说的“膈上有寒饮”，指的是中焦虚寒，所以适宜温补。由此可见，前一节说的“寒”，是指寒邪之实；后一节说的“寒”，是指胃气之虚。虽然都称为“寒”，但有虚实之别。实证适宜涌吐，涌吐则邪气消散；若是虚证而误用涌吐，会使胃气更加虚弱，病情必定加重。这些关键之处，最应当仔细审察。
又说：凡是胸上部有各种实邪积聚，胸中郁闷疼痛，不能进食，想要让人按压胸部，反而吐出涎沫，每日腹泻十多次，脉搏反而迟缓，但寸脉微滑，这种情况可以使用涌吐法，涌吐之后腹泻就会停止。
又说：太阳病（太阳经受邪所致的病证），经过涌吐治疗后，原本太阳病应当恶寒，现在反而不恶寒，甚至不想穿衣，这是由于涌吐损伤正气导致内热烦扰所致。
按语：此处是因为太阳病证候本不应涌吐却误用了涌吐法，必然导致邪热乘虚侵入胃中，从而引起内烦。
第二条：凡是使用涌吐药，一旦见效（中病）就应停药，不必服完全部剂量。
第三条：寸脉虚弱无力的，切忌使用涌吐法。
Zhang Zhongjing stated: If a patient presents with cold extremities and a pulse that suddenly becomes tight, the pathogenic factor is constrained in the chest. The patient experiences fullness and irritability in the heart region, feels hungry but cannot eat. The disease is located in the chest and should be treated by inducing vomiting (emesis), for which Gouti San (Melon Seed Powder) is suitable. If a patient presents with cold extremities and a pulse that suddenly becomes knotted, this is due to hostile qi (external pathogen) residing in the chest. There is fullness and irritability below the heart, and food cannot enter. The disease is located in the chest and should be treated by inducing vomiting.
It is also stated: When the symptoms resemble those of Guizhi Tang Syndrome (Taiyang Wind-Strike Exterior Deficiency Syndrome), but there is no headache or stiffness in the neck, and the cun pulse is slightly floating, with a sensation of stuffiness and hardness in the chest, along with qi rushing up to the throat causing difficulty in breathing, this indicates cold pathogen in the chest. It should be treated by inducing vomiting, for which Gouti San (Melon Seed Powder) is suitable. In Shaoyin Disease (disease of the Shaoyin channel), if food is vomited immediately upon entering the mouth, accompanied by a feeling of nausea and desire to vomit without actual expulsion, and initially presenting with cold extremities and a string-tight and slow pulse, this indicates excess in the chest. Purging is contraindicated; instead, emesis should be induced. However, if there is cold fluid retention above the diaphragm causing dry retching, emesis is contraindicated. Urgent warming is required, for which Sini Tang (Frigid Extremity Decoction) is suitable.
Commentary: In the preceding section, "cold in the chest" refers to excess cold pathogen, hence emesis is indicated. In the latter section, "cold fluid above the diaphragm" refers to middle-jiao cold deficiency, hence warming is appropriate. Thus, the "cold" mentioned in the first section refers to the excess nature of cold pathogen, while the "cold" in the second section refers to the deficiency of stomach qi. Although both are termed "cold," they differ in excess and deficiency. Excess conditions are suitable for emesis, which disperses the pathogen; however, applying emesis to deficiency conditions will further deplete stomach qi and exacerbate the illness. These critical points require careful examination.
It is also stated: Regarding various excess patterns in the upper chest, characterized by stifling pain in the chest, inability to eat, a desire for abdominal pressure, yet expectoration of saliva, and diarrhea occurring more than ten times a day with a generally slow pulse but a slightly slippery cun pulse, this condition can be treated by inducing vomiting. After emesis, the diarrhea will cease.
It is also stated: In Taiyang Disease (disease of the Taiyang channel), if emesis is applied, and although Taiyang disease typically presents with aversion to cold, the patient now shows no aversion to cold and even dislikes wearing clothes, this indicates internal heat and irritability caused by the damaging effects of emesis.
Commentary: This occurs because emesis was incorrectly applied to a Taiyang pattern where it was not indicated. Consequently, pathogenic heat enters the stomach through the deficiency created, leading to internal irritability.
1. Food stagnation located in the upper wan (upper epigastrium) should be treated by inducing vomiting.
2. When using emetic drugs, stop as soon as the desired effect is achieved (zhongbing); there is no need to consume the entire dose.
3. If the cun pulse is weak and powerless, emesis is strictly contraindicated.