酒客病不可与桂枝汤得汤则呕以酒客不喜甘故也
大枣甘草甘味动呕也
凡服桂枝汤吐者其后必吐脓血也
大凡服桂枝汤即吐者胸膈湿热郁遏桂枝益其膈热下咽即吐缘其胃气上逆心下痞塞肺郁生热无路下达桂枝辛温之性至
胸而出不得入胃腑而行经络是以吐也其后湿热瘀蒸必吐脓血此宜凉辛清利之剂不宜辛温也
桂枝本为解肌若其人脉浮紧发热汗不出者不可与也常须识此勿令误也
桂枝本解肌表以散风邪若其人脉浮而紧发热汗不出者是寒伤营血营伤则束其卫气是当去芍药之泄营血而用麻黄以泄
卫气桂枝不可与也与之表寒不解反益经热是谓之误风家用桂枝所以不助经热者以其皮毛无寒孔窍不闭无须麻黄发表但以
芍药之酸寒泄其营血桂枝之辛温通其经络血热自能外达若伤寒服之卫郁莫泄经热愈增是助邪也
寒者天地闭藏之气也皮毛未合寒气内入伤其营阴则窍阖而营闭营性升发营欲泄而寒闭之欲泄不能则外乘阳位而束卫
气是以病也
太阳病或已发热或未发热必恶寒体疼呕逆脉阴阳俱紧者名曰伤寒
阳郁则发热阴气外束则恶寒寒闭皮毛经气不得通达则壅遏而为痛经络郁闭卫气遏逼浊阴上逆则为呕逆经脉束迫不得
发越则尺寸俱紧
酒客（长期饮酒者）患病，不可给予桂枝汤；若服用桂枝汤则会引起呕吐，这是因为酒客不喜欢甘味的原因。
大枣、甘草具有甘味，容易引发呕吐。
凡是服用桂枝汤后出现呕吐的人，其后必然会出现吐脓血的症状。
大凡服用桂枝汤即发生呕吐的，是因为胸膈部位湿热郁结遏阻，桂枝会加重膈部的热邪，药液咽下后立即呕吐。这是由于胃气上逆，心下部痞塞不通，肺气郁滞产生热邪，没有途径向下通达。桂枝辛温的药性到达胸部而出，不能进入胃腑并运行于经络，因此导致呕吐。此后湿热瘀积蒸腾，必然会导致吐脓血，这种情况适宜使用凉性、辛味、清利性质的方剂，而不宜使用辛温性质的药物。
桂枝原本是用来解除肌表邪气的，如果患者脉象浮紧、发热且无汗，则不可给予桂枝汤。必须时刻牢记这一点，不要犯错误。
桂枝本意是解除肌表以疏散风邪，但如果患者脉象浮而紧、发热且无汗，这是寒邪损伤了营血，营血受损则会束缚卫气，此时应当去掉芍药的泄营血作用，而使用麻黄来宣泄卫气，桂枝不可给予。如果给予桂枝，表寒不解，反而会增加经脉的热邪，这叫做误治。风家用桂枝所以不助长经脉热邪的原因，是因为皮毛没有受寒，孔窍没有闭塞，不需要麻黄发表，只是用芍药的酸寒之性来泄营血，用桂枝的辛温之性通调经络，血热自然能向外发散。如果是伤寒服用桂枝，卫气郁闭无法宣泄，经脉热邪更加增加，这是助长邪气。
寒，是天地闭藏之气。皮毛未闭合时寒气内入，损伤营阴，则腠理闭合而营气闭阻。营气性质升发，想要宣泄却被寒邪闭阻，想宣泄而不能，于是向外乘袭阳位而束缚卫气，因此生病。
太阳病，或者已经发热，或者尚未发热，必定伴有恶寒、身体疼痛、呕吐逆气、脉象寸关尺三部俱紧的情况，命名为伤寒。
阳气郁结则发热，阴气在外束缚则恶寒。寒邪闭阻皮毛，经气不得通达，则壅滞遏阻而产生疼痛。经络郁闭，卫气被遏逼，浊阴上逆则产生呕吐逆气。经脉被束迫，不得发越，则寸部和尺部脉象都紧。
肝藏营血，寒邪伤及营分，行使闭藏的令状，营血不能宣通，因此无汗。营气越是闭阻就越要宣泄，宣泄而不通畅则卫气郁结而生寒。麻黄汤之所以能开泄皮毛而宣泄卫气郁结。
For patients who are habitual wine drinkers (Jiu Ke, individuals with a history of chronic alcohol consumption), Guizhi Tang (Cinnamon Twig Decoction) should not be administered; if taken, it will induce vomiting because these patients generally dislike sweet flavors.
Dazao (Jujube Fruit, Ziziphus Jujuba) and Gancao (Licorice Root, Glycyrrhiza uralensis) possess sweet properties and tend to provoke vomiting.
In general, those who vomit after taking Guizhi Tang (Cinnamon Twig Decoction) will subsequently expectorate pus and blood.
Generally speaking, immediate vomiting after ingesting Guizhi Tang (Cinnamon Twig Decoction) indicates damp-heat stagnation and obstruction in the chest and diaphragm. The acrid-warm nature of Guizhi (Ramulus Cinnamomi) exacerbates heat in the diaphragm; upon swallowing, immediate vomiting occurs due to rebellious Stomach Qi, epigastric fullness and obstruction, and Lung Qi stagnation generating heat with no pathway for downward diffusion. The acrid-warm property of Guizhi reaches the chest but cannot enter the Stomach Fu organ or circulate through the meridians, thus causing vomiting. Subsequently, damp-heat stasis steaming and fermenting will inevitably lead to expectoration of pus and blood. In such cases, cooling, acrid, and draining agents are appropriate, whereas acrid-warm substances are contraindicated.
Guizhi (Ramulus Cinnamomi) is originally intended to release the muscle layer (Ji Biao). If the patient presents with a floating-tight pulse, fever, and absence of sweating, Guizhi Tang (Cinnamon Twig Decoction) must not be given. This principle must always be kept in mind to avoid error.
Guizhi (Ramulus Cinnamomi) naturally releases the exterior to disperse wind pathogens. However, if the pulse is floating and tight, accompanied by fever and anhidrosis, this indicates cold damaging the Ying Blood (Nutritive Blood). Damage to Ying constrains the Wei Qi (Defensive Qi). In this scenario, Shaoyao (Radix Paeoniae Alba/Rubra) should be removed to prevent draining Ying, and Mahuang (Herba Ephedrae) should be used to vent Wei Qi. Guizhi (Ramulus Cinnamomi) is contraindicated. Administering it fails to resolve the exterior cold and instead increases heat in the meridians, constituting a therapeutic error. Wind-pathogen practitioners use Guizhi without aggravating meridian heat because the skin pores are not closed by cold, and Ma Huang is unnecessary for releasing the exterior. They rely on the sour-cold nature of Shaoyao to drain Ying and the acrid-warm nature of Guizhi to unblock meridians, allowing blood heat to dissipate outward. If Guizhi is taken for Cold Damage (Shang Han), Wei Qi remains stagnant and cannot vent, increasing meridian heat and aiding the pathogen.
Cold is the qi of heaven and earth's closure and storage. When the skin pores are not yet closed, cold qi enters internally, damaging Ying Yin (Yin aspect of Nutritive Level). Consequently, the couli (pores) close, and Ying becomes obstructed. Since Ying has a rising and diffusing nature, it seeks to vent but is blocked by cold. Unable to vent, it attacks the Yang positions externally and constrains Wei Qi, resulting in disease.
Taiyang Disease (Disease of the Taiyang Channel) may present with fever already established or not yet established, but it invariably involves aversion to cold, body pain, vomiting and regurgitation, and a pulse that is tight at both cun and chi positions. This pattern is named Shang Han (Cold Damage).
Yang qi stagnation leads to fever; external constraint by Yin qi causes aversion to cold. Cold closing the skin pores prevents Jing Qi (Meridian Qi) from circulating freely, leading to congestion and pain. Meridian stagnation and blockage cause Wei Qi to be suppressed, forcing turbid Yin to rebel upward, resulting in vomiting and regurgitation. Constriction of the meridians prevents free expression, causing the pulse to be tight at both the cun (inch) and chi (cubit) positions.
The Liver stores Ying Blood. Cold injuring the Ying level enforces its storing function, preventing the circulation of Ying Blood, hence the absence of sweating. As Ying becomes more obstructed, it attempts to vent; however, lack of smooth flow causes Wei Qi to stagnate and generate cold. Mahuang Tang (Ephedra Decoction) opens the skin pores and vents Wei Qi stagnation.