发汗。或云当得汗解。或云当发汗更发汗。并发汗。宜桂枝汤者数方。是用桂枝发汗也
。复
云。无汗不得服桂枝。又曰汗家不得重发汗。又曰发汗过多者。却用桂枝甘草汤。是闭汗也
。一药二用。如何说得。仲景发汗与本草之义相通为一。答曰。本草云。桂味辛甘热无毒。
能为百药长通血脉止烦出汗者。是调血而汗自出也。仲景云。脏无他病。发热自汗者。此卫
气不和也。又云。自汗者为荣气和。荣气和则外不谐。卫气不与荣气相和谐也。荣气和则愈
。故皆用桂枝汤调和荣卫。荣卫既和。则汗。自出矣。风邪由此而解非桂枝能开腠理发出汗
也。以其固闭荣血。卫气自和。邪无容地而出矣。其实则闭汗孔也。昧者不解闭汗之意。凡见病
者。便用桂枝汤发汗。若与中风自汗者合其效桴鼓。因见其取效而病愈。则曰。此桂枝发出
汗也。遂不问伤寒无汗者。亦与桂枝汤误之甚矣。故仲景言无汗不得服桂枝。是闭汗孔也。
又云。发汗多义（手冒）心。心悸欲得按者。用桂枝甘草汤。是亦闭汗孔也。又曰汗家不得
重
发汗。若桂枝汤发汗。是重发汗也。凡桂枝条下言发字。当认作出字。是汗自然出也。非若
麻黄能开腠理而发出汗也。本草出汗二字。上文有通血脉一句。是非三焦卫气皮毛中药。是
为荣血中药也。如是则出汗二字。当认作荣卫和自然汗出。非桂开腠理而发出汗也。故后人
用
桂治虚汗。读者当逆察其意则可矣。噫神农之作于其前。仲景之述于其后。前圣后圣其揆一
也。
发汗。有人说应当通过出汗来解除病邪。有人说应当先发汗，然后再发汗。凡是使用桂枝汤的方剂，都是利用桂枝来发汗。
又说，没有汗出的情况不得服用桂枝汤。又说，平素多汗的人不得再次强行发汗。又说，发汗过多的人，却使用桂枝甘草汤。这是收敛止汗的方法。
一味药有两种相反的用途，这怎么解释呢？张仲景关于发汗的理论和本草学的意义是相通且统一的。
回答说：本草记载，桂枝味辛、甘，性热，无毒。它能作为百药的统领，通行血脉，消除烦闷，促使汗出。这是通过调和血液而使得汗液自然流出。
张仲景说，内脏没有其他病症，出现发热并自汗的情况，这是卫气不和。
又说，自汗出的是因为营气和调，但营气调和则体表不和谐，即卫气不与营气相和谐。如果营气调和，病就会痊愈。
所以都使用桂枝汤来调和营卫。营卫既已调和，那么汗液就会自然流出。风邪因此得以解除，并不是桂枝能打开腠理发出汗液。
而是因为它固摄营血，使卫气恢复和谐，邪气无处容身而排出体外。其实质是关闭汗孔。
愚昧的人不理解“闭汗”的含义，凡见到病人，就使用桂枝汤来发汗。如果这与中风自汗的患者相符，其疗效如击鼓应声般迅速。
因为看到它取效且病愈，就说：“这是桂枝发出的汗。”于是就不问伤寒无汗的患者，也给予桂枝汤，这是很大的错误。
所以张仲景说无汗不得服用桂枝汤，是因为（桂枝）是关闭汗孔的。
又说，发汗过多导致心下悸动，心中悸动想要按压缓解的，使用桂枝甘草汤。这也是关闭汗孔的方法。
又说，平素多汗的人不得再次强行发汗。如果用桂枝汤发汗，就是再次强行发汗。
凡是桂枝条下提到的“发”字，应当理解为“出”，意思是汗液自然流出。不像麻黄那样能打开腠理而发出汗液。
本草中“出汗”二字，上文有“通血脉”一句。这说明它不是作用于三焦、卫气、皮毛的药物，而是作用于营血的药物。
如果是这样，那么“出汗”二字，应当理解为营卫调和后自然汗出，并不是桂枝打开腠理而发出汗液。
所以后人用桂枝治疗虚汗，读者应当逆向体察其中的意旨就可以了。
唉！神农在之前著书，张仲景在之后阐述。前圣和后圣的道理是一致的。
Diaphoresis. Some say that resolution should be achieved through sweating. Others say that one should induce sweating, and then induce sweating again. All formulas employing Guizhi Tang (Cinnamon Twig Decoction) utilize Guizhi (Cinnamon Twig) to induce diaphoresis.
It is further stated that Guizhi (Cinnamon Twig) must not be administered when there is no sweat. It is also stated that individuals who are prone to sweating must not undergo repeated forced diaphoresis. Furthermore, for those who have suffered from excessive sweating, Guizhi Gancao Tang (Cinnamon Twig and Licorice Decoction) is used. This serves to close the pores and stop sweating.
How can a single herb have two opposing functions? Zhang Zhongjing’s understanding of diaphoresis is consistent with the principles of Materia Medica.
The answer is: The Materia Medica states that Guizhi (Cinnamon Twig) has an acrid, sweet, and hot nature, and is non-toxic. It acts as the leader among herbs, unblocking the blood vessels, relieving irritability, and inducing sweat. This mechanism works by harmonizing the blood, causing sweat to emerge naturally.
Zhang Zhongjing states: When the internal organs are free from other pathologies, but fever and spontaneous sweating occur, this indicates disharmony of Wei Qi (Defensive Qi).
He also states: Spontaneous sweating occurs because Ying Qi (Nutritive Qi) is harmonious, yet the exterior remains discordant; specifically, Wei Qi (Defensive Qi) does not harmonize with Ying Qi (Nutritive Qi). If Ying Qi (Nutritive Qi) becomes harmonious, recovery ensues.
Therefore, Guizhi Tang (Cinnamon Twig Decoction) is used to harmonize Ying Qi (Nutritive Qi) and Wei Qi (Defensive Qi). Once Ying Qi (Nutritive Qi) and Wei Qi (Defensive Qi) are harmonized, sweat will emerge naturally. The Wind Pathogen is thereby resolved; it is not that Guizhi (Cinnamon Twig) opens the Cou Li (skin and hair follicles) to force out sweat.
Rather, it consolidates Ying Blood (Nutritive Blood), allowing Wei Qi (Defensive Qi) to become harmonious, leaving no room for pathogens, which are thus expelled. Its actual function is to close the sweat pores.
Ignorant practitioners fail to understand the meaning of "closing the sweat pores." Upon seeing any patient, they indiscriminately administer Guizhi Tang (Cinnamon Twig Decoction) to induce diaphoresis. If this coincides with patients suffering from Wind Strike with spontaneous sweating, the therapeutic effect is immediate and effective, like a drumstick striking a drum.
Seeing its efficacy and the subsequent cure, they conclude: "This sweat was induced by Guizhi (Cinnamon Twig)." Consequently, they fail to distinguish between Cold Damage cases without sweat and administer Guizhi Tang (Cinnamon Twig Decoction) erroneously, which is a grave mistake.
Thus, Zhang Zhongjing states that Guizhi (Cinnamon Twig) must not be taken when there is no sweat, precisely because it closes the sweat pores.
He also states: When excessive sweating leads to palpitations in the heart region, and the patient desires pressure on the chest to alleviate discomfort, Guizhi Gancao Tang (Cinnamon Twig and Licorice Decoction) is used. This too serves to close the sweat pores.
Furthermore, it is stated that individuals prone to sweating must not undergo repeated forced diaphoresis. Using Guizhi Tang (Cinnamon Twig Decoction) to induce sweating in such cases constitutes repeated forced diaphoresis.
Wherever the character "fa" (to emit/release) appears under the entry for Guizhi (Cinnamon Twig), it should be understood as "chu" (to come out), meaning sweat emerges naturally. It does not open the Cou Li (skin and hair follicles) to force out sweat, unlike Mahuang (Ephedra Herb).
In the Materia Medica, the phrase "induces sweat" is preceded by "unblocks the blood vessels." This indicates that it is not an herb acting on the San Jiao (Triple Burner), Wei Qi (Defensive Qi), or the skin and hair follicles, but rather an herb acting on Ying Blood (Nutritive Blood).
If this is the case, then the term "induces sweat" should be interpreted as sweat emerging naturally due to the harmony of Ying Qi (Nutritive Qi) and Wei Qi (Defensive Qi), not as Guizhi (Cinnamon Twig) opening the Cou Li (skin and hair follicles) to force out sweat.
Therefore, when later practitioners use Guizhi (Cinnamon Twig) to treat deficiency-type sweating, readers should interpret its intent inversely.
Alas! Shennong authored his work beforehand, and Zhang Zhongjing expounded upon it afterwards. The principles of the sages of old and the sages of later times are identical.