寒、通、泻经隧水湿。
苦寒。能泻肾经及隧道水湿。直达水气所结之处。以攻决为用。为下水之圣药。主十二
种水
。大腹肿满。（名水蛊、嘉言曰∶胃为水谷之海、五脏六腑之源、脾不能散胃之水精于肺、
而病于中、肺不能通胃之水道于膀胱、而病于上、肾不能司胃之关时其输泄、而病于下、以
致积水浸淫、无所底止、好古曰∶水者、脾肺肾三经所主、有五脏六腑、十二经之部分、上
头面、中四肢、下腰脚、外皮肤、中肌肉、内筋骨、脉有尺寸之殊、浮沉之别、不可轻泻药、
当知病在何经何脏、方可用之、按水肿、有痰裹、食积、瘀血、致清不升、浊不降而成者、
有湿热相生、隧道阻塞而成者、有燥热冲击、秘结不通而成者、是证属有余、有服寒凉、伤
饮食、中气虚衰而成者、有大病后、正气衰惫而成者、有小便不通、水液妄行、脾不能制而
成者、证属不足、宜分别治之、然其源多由中气不足而起、丹溪曰∶水病当以健脾为主、使
脾
参苓为君、视所挟证加减、苟徒用利水药、多致不起。）
疝瘕积聚。痞热宿食。痰迷癫痫。去水极神。损真极速。大实大水。可暂用之。否则宜
禁。皮赤肉黑。根作连珠。
重实者良。面裹煨熟用。（或用甘草荠 汁浸三日、其水如墨、以清为度、再
面裹煨。）瓜蒂为使。恶远志。反甘草。（仲景治心下留饮、与甘草同用、取其相反以立功、
有治水肿及肿毒者、以甘遂末敷肿处、浓煎甘草汤服之、其肿立消、二物虽相反、感应如此
其神。）
性味寒、通，能泻除经络隧道中的水湿。
味苦，性寒。能够泻除肾经及人体隧道（指经络、脏腑间的细微通道）中的水湿。药力直达水气凝结之处，以攻逐决裂水邪为功效，是下水利水的圣药。主治十二种水肿病。大腹肿胀满闷。（称为水蛊。嘉言说：胃是水谷之海，五脏六腑的源头。脾不能将胃中吸收的水精输送到肺，导致病变在中焦；肺不能疏通胃中的水道至膀胱，导致病变在上焦；肾不能主管胃中水液的开阖输泄，导致病变在下焦。从而导致积水浸淫泛滥，没有止境。好古说：水液由脾、肺、肾三经所主，涉及五脏六腑、十二经脉的各个部分，上至头面，中至四肢，下至腰脚，外达皮肤，内入肌肉，深入筋骨。脉象有寸尺之分，浮沉之别，不可轻易使用泻下药，应当知晓病在何经何脏，方可使用。按水肿而言，有因痰饮包裹、食积、瘀血，导致清阳不升、浊阴不降而形成的；有因湿热相生、隧道阻塞而形成的；有因燥热冲击、秘结不通而形成的。这些证候属于实证有余。也有因服用寒凉药物损伤饮食，导致中气虚衰而形成的；有大病之后，正气衰惫而形成的；有小便不通，水液妄行，脾不能制约而形成的。这些证候属于虚证不足。应当分别治疗。然而其根源多由中气不足引起。丹溪说：治疗水病应当以健脾为主，使脾参苓作为君药，根据兼夹证候进行加减。如果单纯使用利水药，大多会导致病情恶化甚至死亡。）
疝气、瘕聚积聚。痞块、热邪、宿食。痰迷心窍导致的癫痫。去水效果极神奇。但损伤真气速度极快。对于大实大水的重症，可以暂时使用它。否则应当禁忌。皮色赤红，肉质黑，根部呈连珠状。
质地坚实沉重的品质优良。用面粉包裹后煨熟使用。（或者用甘草和荠菜的汁液浸泡三天，直到泡出的水像墨一样黑，以水变清为限度，再用面粉包裹煨熟。）瓜蒂为使药。畏远志。反甘草。（张仲景治疗心下留饮时，与甘草同用，取其相反相成的原理以立功。有治疗水肿及肿毒的案例，用甘遂末敷于肿处，浓煎甘草汤内服，肿胀立即消退。这两味药虽然相反，但感应如此神奇。）
Nature: Cold, penetrating. Action: Drains water-dampness from the meridians and collaterals (tunnel-like passages).
Bitter and cold. Capable of draining water-dampness from the Kidney meridian and the body's tunnels (referring to fine channels between meridians and organs). Its medicinal force reaches directly to the sites where water-qi is knotted, utilizing attack and resolution as its function. It is the supreme medicine for promoting urination and removing water. It primarily treats twelve types of edema. Abdominal distension and fullness. (Known as "Shui Gu" [Water Distortion]. Jiayan stated: The Stomach is the sea of water and grain, the source of the five zang and six fu organs. If the Spleen cannot distribute the refined essence of water from the Stomach to the Lung, pathology arises in the middle; if the Lung cannot unblock the water pathways from the Stomach to the Bladder, pathology arises in the upper; if the Kidney fails to govern the opening and closing and transport/excretion of water from the Stomach, pathology arises in the lower. This leads to accumulating water flooding without cessation. Haogou stated: Water is governed by the Spleen, Lung, and Kidney meridians, involving parts of the five zang, six fu, and twelve meridians, extending to the head and face above, limbs in the middle, waist and legs below, skin externally, muscles internally, and bones/tendons deeply. Pulse diagnoses vary by cun/cunchi positions and floating/sinking qualities; one should not lightly use purgative drugs. One must know which meridian and zang-fu are affected before using them. Regarding edema, some cases arise from phlegm encasement, food stagnation, or blood stasis causing clear yang to fail to ascend and turbid yin to fail to descend; some arise from mutual generation of damp-heat blocking the tunnels; some arise from dry-heat impact causing constipation and blockage. These syndromes belong to excess/fulfillment. Other cases arise from taking cold-cooling medicines damaging digestion, leading to deficiency of middle qi; or from post-major illness exhaustion of righteous qi; or from inability to urinate with water fluids flowing recklessly due to Spleen failure to control. These syndromes belong to deficiency/inadequacy. Treatments should be differentiated. However, the root cause often stems from insufficiency of middle qi. Danxi stated: Treating water diseases should prioritize strengthening the Spleen, using Shen Ling Bai Zhu San (Ginseng, Poria, Atractylodes Macrocephala Powder) as the sovereign drug, modified according to accompanying syndromes. If only diuretics are used, it often leads to fatal outcomes.)
Hernia, mass accumulation. Epigastric fullness, heat, retained food. Phlegm confusing the mind causing epilepsy. Extremely effective at removing water, but rapidly damages true qi. For severe excess and massive water retention, it may be used temporarily. Otherwise, it is contraindicated. Skin is reddish, flesh is black, roots resemble a string of pearls.
Those that are heavy and solid are superior. Wrap in flour and roast until cooked. (Alternatively, soak in juice of Gancao [Licorice] and Qimai [Shepherd's Purse] for three days, until the liquid turns black like ink, then wash until clear, and wrap in flour to roast.) Gudi (Melon Tip) serves as the assistant. Opposed to Yuanzhi (Polygala Root). Incompatible with Gancao (Licorice). (Zhang Zhongjing used it together with Gancao to treat retained fluid under the heart, leveraging their incompatibility to achieve therapeutic effect. There are cases treating edema and swelling/toxins where Gan Su powder is applied topically to the swollen area while strong decoction of Gancao is taken orally, resulting in immediate reduction of swelling. Although these two herbs are incompatible, their interaction is so miraculous.)