通，祛风湿
气寒善行，味苦性燥（行水故燥）。入脾、胃除湿热，兼入膀胱、小肠。行水道，通关
节，利九窍。
为诸黄、风痹之要药（一味白藓皮汤，治产后风。时珍曰∶世医止施之疮科，浅矣）。
兼
治风疮疥癣，女子阴中肿痛（湿热乘虚客肾与膀胱所致）。
根黄白而心实。取皮用。恶桑螵蛸、桔梗、茯苓、萆 。
通，祛风湿，补下焦
甘苦性平。入足阳明、厥阴（胃、肝）。祛风去湿，以固下焦（阳明主肉，属湿。厥阴
主筋，属风），补肝虚（去风），坚筋骨（风湿去，则筋骨坚），益精明目。
治风寒湿痹，腰痛久冷，关节老血，膀胱宿水，阴痿失溺，茎痛遗浊，痔 恶疮（诸病
皆阳明湿热流入下焦，萆 能除浊厘清，古方有萆 厘清饮。史国信云∶若欲兴阳，先滋筋
力。若欲便清，先分肝火。《万金护命方》云∶凡人小便频数、便时痛不可忍者，此疾必因
大肠秘热不通，水液只就小肠，大肠愈加干竭，甚则身热心躁，思水，即重证也。此疾本因
贪酒色，或过食辛热、荤腻之物，积有热毒，腐物、瘀血，乘虚流入小肠，故便时作痛也。
此便数而痛，与淋证涩而痛不同，宜用萆 一两，盐水炒，为末，每服二三钱，使水道转入
大肠，仍以葱汤频洗谷道，令气得通，则便数及痛自减也。肾有二窍，淋证出于溺窍，浊证
出于精窍）。
有黄、白二种，黄长、 （音硬），白虚、软，软者良。薏苡为使。畏大黄、柴胡、前
胡。忌茗、醋（时珍曰∶萆 、菝 、土茯苓，形不同而主治不甚相远，岂一类数种乎？萆
根细长、浅白，菝 根作块而黄）。
（白藓皮）性味通利，能祛除风湿。其气寒而善于走窜，味苦且性质燥烈（因为能行水，所以显得燥）。它入脾、胃经以清除湿热，同时兼入膀胱、小肠经。它能疏通水道，通达关节，使九窍通畅。
它是治疗各种黄疸、风痹的重要药物（有一味白藓皮汤，用于治疗产后风邪。李时珍说：世间的医生只把它用于疮疡科，见识太浅了）。
它还兼治风疹疥癣，以及女子外阴肿痛（这是由于湿热乘虚侵袭肾脏与膀胱所致）。
（萆薢）性味通利，能祛除风湿，并补益下焦。其味甘、苦，性平。它入足阳明、足厥阴经（即胃经、肝经）。它能祛风除湿，从而稳固下焦（足阳明胃经主肌肉，归属于湿；足厥阴肝经主筋，归属于风），补益肝之虚损（通过祛风），坚固筋骨（风湿去除后，筋骨自然坚固），增进精气，明亮双目。
它治疗风寒湿邪引起的痹证，腰痛日久且感觉寒冷，关节中的陈旧瘀血，膀胱内的停积水液，阳痿及小便失禁，阴茎疼痛及遗精尿浊，痔疮及恶疮（这些病症都是因为阳明经的湿热流入下焦所致，萆薢能够分清泌浊，古代方剂中有萆薢分清饮。史国信说：如果想要兴阳起痿，必须先滋养筋力。如果想要小便清长，必须先疏泄肝火。《万金护命方》说：大凡人出现小便频数，排尿时疼痛难忍的症状，这种病必定是因为大肠秘结不通，导致水液只能流向小肠，大肠更加干涸枯竭，甚至出现身体发热、烦躁、想喝水的重症。这种病的根本原因在于贪恋酒色，或者过食辛辣、温热、荤腥油腻之物，积聚了热毒，腐败物质和瘀血乘虚流入小肠，所以排尿时会疼痛。这种尿频且痛的情况，与淋证那种涩滞且痛不同，适宜用萆薢一两，用盐水炒制后研成粉末，每次服用二三钱，使水道转向大肠，同时仍需用葱汤频繁清洗肛门，使气机通畅，那么尿频和疼痛自然会减轻。肾有两个窍，淋证是从溺窍排出，浊证是从精窍排出）。
萆薢有黄色和白色两种，黄色的质地坚硬，白色的质地空虚、柔软，柔软的品种质量较好。薏苡仁作为它的辅药。它畏忌大黄、柴胡、前胡。禁忌饮茶、醋（李时珍说：萆薢、菝葜、土茯苓，外形不同但主治功效不太相近，难道是一类植物的几种吗？萆薢根细长、颜色浅白；菝葜根呈块状、颜色发黄）。
(Bai Xian Pi / Cortex Dictamni) possesses a penetrating nature and dispels wind-dampness. Its qi is cold and agile, its flavor bitter and nature drying (it is drying because it promotes water metabolism). It enters the Spleen and Stomach channels to drain damp-heat, and concurrently enters the Bladder and Small Intestine channels. It unblocks water passages, opens joints, and benefits the nine orifices.
It is a key herb for treating various types of jaundice and wind-bi syndrome (a single-herb decoction of Bai Xian Pi treats postpartum wind pathogen. Li Shizhen stated: Contemporary physicians only apply it to dermatology, which is superficial).
It also treats wind-induced sores, scabies, tinea, and swelling and pain in the female vagina (caused by damp-heat invading the Kidney and Bladder due to deficiency).
(Bi Xie / Rhizoma Dioscoreae Hypoglaucae) possesses a penetrating nature, dispels wind-dampness, and tonifies the Lower Jiao. Its flavor is sweet and bitter, and its nature is neutral. It enters the Foot-Yangming and Foot-Jueyin channels (Stomach and Liver). It dispels wind and removes dampness to stabilize the Lower Jiao (the Yangming channel governs flesh and is associated with dampness; the Jueyin channel governs sinews and is associated with wind), tonifies Liver deficiency (by dispelling wind), strengthens sinews and bones (when wind-dampness is removed, sinews and bones become firm), benefits essence, and brightens the eyes.
It treats bi syndrome caused by wind-cold-dampness, chronic lower back pain with a sensation of cold, old blood stagnation in joints, retained water in the Bladder, impotence, urinary incontinence, penile pain, and seminal emission/turbid urine, as well as hemorrhoids and malignant sores (these conditions all result from damp-heat flowing into the Lower Jiao from the Yangming channel; Bi Xie can separate the clear from the turbid. Ancient formulas include Bi Xie Fen Qing Yin. Shi Guoxin said: If one wishes to promote yang, one must first nourish the sinews. If one wishes for clear urination, one must first subdue Liver fire. The *Wanjin Huming Fang* states: When a person suffers from frequent urination with unbearable pain during voiding, this disease is necessarily due to constipation and blockage in the Large Intestine, causing fluid to flow only into the Small Intestine, further depleting the Large Intestine. This may lead to severe symptoms such as fever, restlessness, and thirst. The root cause is indulgence in alcohol and sex, or excessive consumption of spicy, hot, meaty, or greasy foods, accumulating heat toxins. Rotting matter and blood stasis invade the Small Intestine due to deficiency, causing pain during urination. This frequency and pain differ from strangury, which is characterized by obstruction and pain. One should use 1 liang of Bi Xie, stir-fried with salt water, ground into powder, taken 2-3 qian per dose, to redirect the water pathway to the Large Intestine. Simultaneously, wash the anus frequently with green onion soup to ensure qi circulation, thereby reducing frequency and pain. The Kidney has two orifices; strangury originates from the urinary orifice, while turbidity originates from the seminal orifice).
There are yellow and white varieties. The yellow variety is long and hard (*ying*), while the white variety is hollow and soft; the soft variety is superior. Coix Seed (*Yi Yi Ren*) serves as its assistant. It is incompatible with Da Huang, Chai Hu, and Qian Hu. Tea and vinegar are contraindicated (Li Shizhen noted: Bi Xie, Ba Qia, and Tu Fu Ling have different appearances but similar therapeutic effects; could they be species of the same genus? Bi Xie roots are slender and pale white; Ba Qia roots are tuberous and yellow).