半夏味辛气平，辛则开结，平则降逆，为治呕吐胸满之要药。呕吐胸满者，少阳证也，
故小柴胡汤不能缺此。推之治心痞、治腹胀、治咳、治咽喉不利，一皆开结降逆之功。要其
所以
用半夏者，率以二陈汤能润大便，半硫丸能治虚秘冷秘，谓润而非燥，究亦何尝不燥也
，遇津亏无湿之人投之，立贻祸殃。惟仲圣取其长而弃其短，胃反为脾伤不磨，非有滞浊，
乃佐之以人参，益之以白蜜，俾半夏之燥性尽失，而胃中之谷气以行。又竹叶石膏汤、麦门
冬汤、温经汤三证，亦未可以半夏劫液者。乃其所伍者，为竹叶石膏人参麦冬甘草粳米阿胶
丹皮之属，是亦化半夏之燥而展其开降之能，所谓化而裁之存乎变也。
小青龙汤曰渴者去半夏，小柴胡汤曰渴者去半夏，此可为半夏非不燥之明征。然半夏之
燥，
小青龙汤若微利者去麻黄加荛花，盖利则水气不径趋膀胱，更以麻黄升太阳，则水道益
涩，水气必泛而为胀满，太阴篇所谓下利清谷不可攻表汗出必胀满也。荛花本经主荡涤肠胃
留癖利水道，则微利不至成滞下，而在上之水气亦去。且其用在花，走里兼能走表，故本经
并主伤寒温疟饮食寒热邪气。若以茯苓泽泻治微利，则表邪亦从而陷之矣，此仲圣所以有取
于荛花也。
菟丝子汁去面 ，徐氏不解，叶香岩谓升少阴，徐氏复不信，不知此最易晓耳。菟丝延
草木则根断，子中脂膏最足，故补肾精而主升。面为阳明之脉，而菟丝甘辛而温，能由阳明
经上入于面，以施其滑泽之功，面 焉得不去，窃愿以此释徐氏之疑。
脾主肌肉，菟丝以寄生根断之性，补益其脾，故能充卫气而肥健，老学庵笔记谓久服生
疽，
他物补肾，补之而已，此能于补中寓升，故其治精自出溺有余沥，不得以涩剂目之。治
消渴
半夏味辛、气平，辛能开散结滞，平能降逆止呕，是治疗呕吐和胸中胀满的关键药物。出现呕吐和胸满的症状，属于少阳病证，因此小柴胡汤中不能缺少半夏。推而广之，用于治疗心下痞塞、腹部胀满、咳嗽、咽喉不利等症状，都是依靠其开散结滞、降逆气的功效。
考察使用半夏的原因，通常认为二陈汤能润通大便，半硫丸能治疗虚秘和冷秘，看似润泽而非燥烈，但究其本质，又何尝不燥呢？如果遇到津液亏损且体内无湿的患者，误用半夏，立刻就会招致祸患。只有张仲景取其长处而弃其短处：对于胃反（脾胃虚弱导致食物不消化），是因为脾伤无法磨化水谷，并非有实邪阻滞，所以佐以人参，加入白蜜，使半夏的燥性完全丧失，从而推动胃中的谷气运行。另外，在竹叶石膏汤、麦门冬汤、温经汤这三个方证的配伍中，也不能简单地说半夏会劫夺阴液。因为这些方剂中与半夏配合的药物，如竹叶、石膏、人参、麦冬、甘草、粳米、阿胶、丹皮等，能够化解半夏的燥性并发挥其开散和降逆的作用，这就是所谓的“变化裁制，存乎一心”。
《伤寒论》中小青龙汤条提到“若渴者，去半夏”，小柴胡汤条也提到“若渴者，去半夏”，这是证明半夏具有燥性的明确证据。然而半夏的燥性……（原文此处中断）
小青龙汤若伴有轻微腹泻，应去掉麻黄，加入荛花。因为腹泻说明水气不直接趋向膀胱，如果再用麻黄升发太阳经之气，水道会更加涩滞，水气必然泛滥而导致胀满，正如太阴篇所说：“下利清谷不可攻表，汗出必胀满。”荛花在《本经》中主治荡涤肠胃中的积滞癖块，通利水道，这样轻微的腹泻就不会变成停滞不下的痢疾，同时在上部的水气也能被去除。而且荛花的药效在于其花，既能走里又能走表，所以《本经》还记载它主治伤寒、温疟、饮食引起的寒热邪气。如果用茯苓、泽泻来治疗轻微腹泻，则会导致表邪内陷，这就是张仲景之所以选用荛花的原因。
菟丝子汁能去除面部黑斑，徐氏对此不理解，叶香岩认为是提升少阴经气，徐氏又表示不信，其实这很容易理解。菟丝子缠绕草木生长，一旦根断，种子中的脂膏最为充足，所以能补肾精且具有升提的特性。面部是阳明经脉所过之处，而菟丝子味甘、辛，性温，能通过阳明经上行至面部，施展其滑润泽肤的功效，面部的黑斑怎能不去除呢？我愿以此解释徐氏的疑惑。
脾主肌肉，菟丝子具有寄生植物根断后仍能生长的特性，能补益脾气，所以能充实卫气，使人身体肥壮健壮。《老学庵笔记》中说久服菟丝子会长痈疽，其他补肾的药物只是单纯的补益，而菟丝子能在补益中寓含升提之意，所以它能治疗精气自出、小便有余沥的症状，不能将其视为单纯的固涩剂。治疗消渴……（原文此处中断）
Banxia (Pinelliae Rhizoma) has a pungent flavor and neutral qi. Pungency can open up stagnation, while neutrality can direct rebellious qi downward. It is a crucial herb for treating vomiting and chest fullness. Vomiting accompanied by chest fullness constitutes a Shaoyang syndrome; therefore, Xiaochaihu Tang (Minor Bupleurum Decoction) cannot omit this herb. Extending this logic, its applications in treating epigastric stuffiness, abdominal distension, cough, and throat obstruction all rely on its efficacy in opening stagnation and directing qi downward.
The rationale for using Banxia is often linked to Erchen Tang (Two-Cured Decoction), which is believed to moisten the large intestine, and Banshui Wan (Half-Sulfur Pill), used for deficiency-type or cold-type constipation. Although it appears moistening rather than drying, upon investigation, does it not possess drying properties? When administered to patients with depleted body fluids and no dampness, it will immediately cause harm. Only Zhang Zhongjing utilized its strengths while discarding its weaknesses. In cases of "Wei Fan" (stomach reversal due to spleen injury and failure to digest), where there is no pathogenic retention but rather spleen deficiency, he paired Banxia with Renshen (Ginseng Radix et Rhizoma) and added Bai Mi (White Honey). This neutralizes the drying nature of Banxia, allowing the grain qi in the stomach to circulate. Similarly, in the formulas Zhuyegao Shitang (Bamboo Leaf and Gypsum Decoction), Maimendong Tang (Ophiopogon Decoction), and Wenjing Tang (Warming the Menses Decoction), one cannot simply claim that Banxia damages fluids. The herbs paired with Banxia—such as Zhuye (Bamboo Leaves), Shigao (Gypsum Fibrosum), Renshen, Maimendong (Ophiopogonis Radix), Gancao (Licorice Root), Jingmi (Glutinous Rice), Ejiao (Donkey-Hide Gelatin), and Danpi (Moutan Cortex)—transform Banxia's drying nature while unleashing its ability to open and descend. This exemplifies the principle of transformation and adaptation.
In the Xiao Qinglong Tang (Minor Blue-Green Dragon Decoction), it states: "If thirsty, remove Banxia." In the Xiaochaihu Tang, it also states: "If thirsty, remove Banxia." These are clear evidences that Banxia is indeed drying. However, the drying nature of Banxia... [Text cuts off]
For Xiao Qinglong Tang, if there is slight diarrhea, Mahuang (Ephedrae Herba) should be removed and Rao Hua (Genkwa Flos) added. Diarrhea indicates that water qi does not flow directly to the Bladder. If Mahuang is used to raise Taiyang qi, the water passages become more obstructed, causing water qi to overflow and lead to distension. This aligns with the statement in the Taiyin chapter: "Diarrhea with undigested food contraindicates attacking the exterior; sweating will inevitably cause distension." Rao Hua, according to the *Shennong Ben Cao Jing*, primarily purges stubborn accumulations in the intestines and promotes urination. Thus, slight diarrhea prevents stagnation/dysentery, and upper-body water qi is also eliminated. Furthermore, its medicinal action resides in the flower, which acts both internally and externally. Therefore, the *Ben Cao Jing* also records its use for treating shanghan (cold damage), wen nue (warm malaria), and dietary-induced chills and fever. If Fuling (Poria) and Zexie (Alisma Rhizoma) were used to treat slight diarrhea, it would cause the exterior pathogen to sink inward. This is why Zhang Zhongjing chose Rao Hua.
The juice of Tusizi (Cuscutae Semen) removes facial pigmentation. Xu Shi did not understand this; Ye Tianshi attributed it to ascending Shaoyin qi, but Xu Shi remained unconvinced. In fact, this is quite easy to understand. Cuscuta vines wrap around host plants; when the root is severed, the seeds contain abundant lipid essence, enabling them to tonify Kidney Essence and exhibit ascending properties. The face is the pathway of the Yangming meridians. Tusizi is sweet, pungent, and warm; it travels via the Yangming meridian upward to the face to exert its lubricating and moisturizing effects. How could facial pigmentation remain? I offer this explanation to resolve Xu Shi's doubts.
The Spleen governs the muscles. Tusizi possesses the characteristic of parasitic roots that continue to function even after detachment, thereby tonifying the Spleen. Consequently, it can enrich Wei Qi (Defensive Qi) and promote physical robustness. The *Laoxue'an Biji* notes that long-term use may cause carbuncles. Other Kidney-tonifying herbs merely tonify, whereas Tusizi incorporates ascending action within tonification. Thus, it treats spontaneous emission of essence and dribbling urine, and should not be classified merely as an astringent. It is used to treat Xiao Ke (Wasting-Thirst)... [Text cuts off]