味苦辛，性寒有毒，入大小肠二经。主下气通二便，祛壅滞气急，退水肿，消风毒，治
腰膝痛，坠胎孕。酒蒸，去皮用。
按∶牵牛子专主水气，故入大小肠经。丹溪曰∶属火善走，有两种，黑者兼水，白者兼
金，病形与证俱衬者用之，然驱逐致虚，不胀满不大便秘者，勿用，仲景治七种湿证及小便
不利，俱不用之，何也？盖受湿之根在下焦，是血分中气病，皆因上焦虚弱，不能气化所致，
若
雷公云∶草金零牵牛子是也，凡使其药，秋末即有实，冬收之，凡用晒干，却入水中淘，
浮者去之，取沉者晒干，用酒蒸，从巳至未，晒干，临用舂去黑皮用。
味苦甘，性平无毒，入脾肾膀胱三经。主风寒湿痹，腰背痛，中风不遂，遍身顽麻，膀
胱宿水，阴痿失溺，利水道，益精明目。薏苡为使，畏葵根、大黄、柴胡、牡蛎，忌牛肉。
按∶萆 之入三经，何也？盖肾受土克，则水脏既衰，肝挟相火而凌土湿，脾主肌肉，
湿郁肌腠，则生热生风，以致营卫不利，关节不利。而萆 长于去水，用之以渗脾湿，则土
安其位，水不受侮矣。然失用令人小便多，小便既多，则肾气得复实？今多泥其入肾，用为
补剂，亦未深原其理耳。
味辛甘，性平无毒，入小肠经。主五淋小便闭，经凝乳闭，难产，积聚，惊悸心烦，
健忘耳聋，声哑鼻塞，痈疮脾疸喜睡，天行瘟疫。
按∶木通利便，专泻小肠，宜疗五淋等证。其惊悸等证，虽属心经，而心与小肠相为表
里，故并治之，脾疸喜睡，此脾之病，皆湿所酿也，利小肠而湿不去乎？瘟疫之来，感天地
不正之气，今受盛之官行，而邪不能容，亦宜疗矣。
【牵牛子】
味苦、辛，性寒，有毒，归大肠经和小肠经。主要功效为降气、通利大小便，祛除壅滞之气引起的喘息急促，消退水肿，消除风毒，治疗腰膝疼痛，以及堕胎。酒蒸后，去皮使用。
按语：牵牛子专门主治水气病，因此归入大肠经和小肠经。朱丹溪说：牵牛子属火，善于走窜，分为两种，黑色的兼治水湿，白色的兼治金（肺），病情与证候相符时使用它。然而，它会因驱逐邪气而导致正气虚弱，如果没有腹胀满和大便秘结的症状，不要使用。张仲景在治疗七种湿证及小便不利时，都不使用它，为什么呢？因为受湿的根源在下焦，这是血分中的气机病变，都是由于上焦虚弱，不能进行气化所致。
雷公说：草金零牵牛子是它的别名。凡是使用这种药物，秋末果实成熟，冬季采收。使用时晒干，然后放入水中淘洗，浮起的去掉，取沉下的晒干，用酒蒸，从巳时到未时，再晒干，临用时捣碎去掉黑皮使用。
【萆薢】
味苦、甘，性平，无毒，归脾经、肾经和膀胱经。主要功效为治疗风寒湿痹，腰背疼痛，中风导致肢体瘫痪，全身麻木，膀胱留饮宿水，阳痿遗尿，通利水道，补益精气、明目。以薏苡仁为使药，畏葵根、大黄、柴胡、牡蛎，忌食牛肉。
按语：萆薢为何归入这三条经络呢？因为肾受到脾土的克制，则水脏（肾）既已衰弱，肝挟带相火而凌犯脾土之湿，脾主肌肉，湿气郁结在肌肉腠理之间，则产生热和风，导致营卫运行不畅，关节不利。而萆薢擅长去除水湿，用它来渗泄脾湿，则脾土安守其位，水湿不再受侮。然而，如果误用会导致小便频多，小便既已频多，肾气反而得以恢复充实吗？现在许多人拘泥于它入肾经，将其用作补剂，这也是没有深入探究其原理的缘故。
【木通】
味辛、甘，性平，无毒，归小肠经。主要功效为治疗五淋、小便闭塞，经血凝滞、乳汁不通，难产，积聚，惊悸心烦，健忘耳聋，声音嘶哑鼻塞，痈疮、脾疸、嗜睡，以及天行瘟疫。
按语：木通通利小便，专门清泻小肠之火，适宜治疗五淋等证候。那些惊悸等证候，虽然属于心经，但心与小肠互为表里，所以一并治疗。脾疸嗜睡，这是脾的病，都是由湿气酿成的，通利小肠而湿气不去除吗？瘟疫的到来，是感受了天地间不正之气，现在受盛之官（小肠）功能正常行使，邪气就不能容纳，也适宜治疗了。
[Qian Niu Zi (Pharbitis Seed)]
Bitter and pungent in flavor, cold in nature, toxic. Enters the Large Intestine and Small Intestine meridians. Primarily descends Qi, unblocks both bowels, dispels stagnant Qi causing wheezing and urgency, reduces edema, eliminates wind-toxicity, treats pain in the waist and knees, and induces abortion. Steamed with wine, peel removed before use.
Note: Qian Niu Zi specializes in treating water-Qi disorders, hence it enters the Large Intestine and Small Intestine meridians. Zhu Danxi stated: It belongs to Fire and is good at moving rapidly. There are two types: the black one combines with Water, and the white one combines with Metal (Lung). Use it when the disease manifestation and syndrome match. However, its expulsion of pathogens can lead to deficiency; do not use it if there is no abdominal fullness or constipation. Zhang Zhongjing did not use it in treating the seven types of dampness syndromes and difficult urination. Why? Because the root of dampness lies in the Lower Jiao, which is a Qi disorder within the Blood aspect, caused by the weakness of the Upper Jiao failing to perform Qi transformation.
Lei Gong said: "Cao Jin Ling" is another name for Qian Niu Zi. When harvesting this herb, collect the mature fruits in late autumn and store them in winter. For use, dry them in the sun, then wash in water. Discard floating seeds, take the sinking ones, dry them again, steam with wine from Si hour (9-11 AM) to Wei hour (1-3 PM), dry again, and crush to remove the black skin before use.
[Bi Xie (Dioscorea Hypoglauca Rhizome)]
Bitter and sweet in flavor, neutral in nature, non-toxic. Enters the Spleen, Kidney, and Bladder meridians. Primarily treats Wind-Cold-Damp Bi obstruction, backache, hemiplegia due to stroke, generalized numbness, retained water in the Bladder, impotence, urinary incontinence, promotes urination, benefits essence, and brightens the eyes. Yi Yi Ren (Coix Seed) serves as the guiding herb. It is incompatible with Kui Gen (Mallow Root), Da Huang (Rhubarb), Chai Hu (Bupleurum), and Mu Li (Oyster Shell). Avoid beef.
Note: Why does Bi Xie enter these three meridians? Because when the Kidney is overcome by Earth (Spleen), the Water organ (Kidney) becomes deficient. The Liver, carrying Ministerial Fire, invades the Dampness of the Spleen. The Spleen governs muscles; when Dampness stagnates in the muscle layers, it generates Heat and Wind, leading to poor circulation of Ying and Wei (Nutritive and Defensive Qi) and joint stiffness. Bi Xie excels at removing water-dampness. Using it to leach out Spleen Dampness allows Earth to maintain its position, preventing Water from being insulted. However, misuse leads to frequent urination. If urination is frequent, does the Kidney Qi recover and become solid? Nowadays, many rigidly adhere to its entry into the Kidney meridian and use it as a tonic, which shows a lack of deep understanding of its principles.
[Mu Tong (Akebia Stem)]
Pungent and sweet in flavor, neutral in nature, non-toxic. Enters the Small Intestine meridian. Primarily treats Wu Lin (Five Types of Strangury), urinary retention, menstrual stasis, lactational obstruction, dystocia, accumulations, palpitations, restlessness, forgetfulness, deafness, hoarseness, nasal congestion, carbuncles, Pi Dan (Spleen Jaundice), lethargy, and epidemic febrile diseases.
Note: Mu Tong promotes urination and specifically drains the Small Intestine, making it suitable for treating Wu Lin and similar syndromes. Although palpitations and other symptoms belong to the Heart meridian, since the Heart and Small Intestine are exterior-interior paired organs, they are treated together. Pi Dan and lethargy are Spleen diseases caused by Dampness; does promoting urination via the Small Intestine fail to remove Dampness? Epidemics arise from inhaling abnormal Qi of Heaven and Earth. Now that the Official of Reception and Transformation (Small Intestine) functions properly, pathogenic factors cannot reside, so it is also suitable for treatment.