水肿为病，皆由真阳怯少，劳伤脾胃，脾胃既寒，积寒化水。盖脾者土地，肾者水也。
肾能
小便不利，外肾或肿，甚则肌肉崩溃，足胫流水，多致不救。歧伯所谓∶水有肤胀、鼓胀、
肠覃、石瘕，种类不一，皆聚水所致。夫水之始起也，目裹微肿，如卧蚕起之状，颈脉动，
喘时咳，阴股间寒，足胫肿，腹乃大，为水已成，以手按其腹，随手而起，如裹水之状，此
其候也。又有蛊胀，腹满不肿；水胀，面目四肢俱肿。
治蛊以水药，治水以蛊药，非其治也。治疗之法，先实脾土，脾实则能舍水，土得其政，
面色纯黄，江河通流，肾水行矣，肿满自消。次温肾水，骨髓坚固，气血乃从。极阴不能化
水而成冰，中焦温和，阴水泮流，然后肿满自消而形自盛，骨肉相保，巨气乃平。然此病证
不可治者有五（五证见巢氏病源），然水病最难治。特须慎于口味，戒房劳谑戏，若不能戒
此，愈而复病者多矣。经云∶治水之法，腰以上肿宜发汗，腰以下肿宜利小便，此至当之论。
然肿满最慎于下，当辨其阴阳。阴水为病，脉来沉迟，色多青白，不烦不渴，小便涩少而清，
大腑多泄，此阴水也，则宜用温暖之剂，如实脾散、复元丹是也；阳水为病，脉来沉数，色
多黄赤，或烦或渴，小便赤涩，大腑多闭，此阳水也，则宜用清平之药，如疏凿饮子，鸭头
丸是也。又有年少，血热生疮，变为肿满，烦渴，小便少，此为热肿。素问所谓∶结阳者肿
四肢是也。
水肿这一病症，都是由于真阳虚弱不足，劳倦损伤了脾胃，脾胃一旦受寒，积聚的寒气转化为水湿。脾属土，肾属水。
如果肾气不能制约水液，导致小便不通利，外生殖器可能肿胀，严重时肌肉溃烂，足胫部流水，大多难以救治。岐伯所说的：水病有肤胀、鼓胀、肠覃、石瘕等，种类不一，都是由水液积聚所致。
水病刚开始发作时，眼睑微微肿胀，像卧蚕隆起的样子，颈部人迎脉搏动，气喘且咳嗽，大腿内侧发冷，足胫部肿胀，腹部随之变大，这是水病已成。用手按压腹部，手松开后凹陷随即弹起，像包裹着水的状态，这就是它的征候。
用治水的药去治疗蛊胀，用治蛊的药去治疗水胀，都不是正确的治疗方法。治疗的原则，首先要充实脾土，脾土充实就能容纳水湿，土气运行正常，面色呈现纯黄色，如同江河通流，肾水得以运行，肿胀自然消除。其次要温补肾水，使骨髓坚固，气血才能顺畅。极阴之气不能化水而结成冰，只有中焦温和，阴寒之水才能化解流动，然后肿胀自然消除，形体自然强健，骨肉相保，正气恢复平和。
然而这种病证中有五种是不可治的（五种证候见《诸病源候论》），但水病是最难治疗的。特别要注意饮食口味，戒除房事和嬉戏过度，如果不能戒除这些，痊愈后复发的人很多。经书说：治疗水病的法则，腰部以上肿胀适宜发汗，腰部以下肿胀适宜利小便，这是最恰当的理论。
但是肿胀满闷最忌讳使用攻下法，应当辨别阴阳。阴水为病，脉象沉迟，面色多青白，不烦躁不口渴，小便涩少且清亮，大便多泄泻，这是阴水，适宜用温暖的方剂，如实脾散、复元丹就是这类；阳水为病，脉象沉数，面色多黄赤，或者烦躁或者口渴，小便赤涩，大便多闭结，这是阳水，适宜用清平的药物，如疏凿饮子、鸭头丸就是这类。
还有年轻人，因血热生疮，转变为肿胀满闷，烦躁口渴，小便少，这称为热肿。《素问》所说：阳气结聚于上部则四肢肿胀，指的就是这种情况。
Edema is a disease caused by the deficiency of True Yang (Zhen Yang), where labor and strain damage the Spleen and Stomach. Once the Spleen and Stomach become cold, accumulated cold transforms into water. The Spleen belongs to Earth, and the Kidney belongs to Water.
If the Kidney fails to control water, leading to difficult urination, the external genitalia may swell. In severe cases, muscles may collapse, fluid flows from the shins, and it often leads to untreatable conditions. As Qibo stated: Water diseases include skin distension (Fu Zhang), drum distension (Gu Zhang), intestinal polyps (Chang Qin), and stone fibroids (Shi Xia), varying in type, all resulting from the accumulation of water.
When water disease first begins, the eyelids swell slightly, resembling the shape of a lying silkworm. The neck pulse moves, there is wheezing and coughing, the inner thighs feel cold, the shins swell, and the abdomen enlarges. This indicates that water has formed. Pressing the abdomen with hand causes the indentation to rise immediately upon release, resembling a bag filled with water; this is its clinical manifestation.
There is also Gu distension, characterized by abdominal fullness without swelling; and Shui distension, where the face, eyes, and four limbs are all swollen.
Treating Gu distension with water-draining medicines, or treating water distension with Gu-removing medicines, is incorrect. The treatment principle is to first strengthen the Spleen Earth. When the Spleen is solid, it can contain water. When Earth functions properly, the complexion becomes purely yellow, rivers flow freely, and Kidney Water circulates, causing swelling and fullness to subside spontaneously. Secondly, warm the Kidney Water so that bone marrow becomes firm and Qi and Blood follow. Extreme Yin cannot transform water into ice; only when the Middle Jiao is warm will Yin water melt and flow. Then swelling and fullness will subside, the body will become robust, bones and flesh will be preserved, and the Great Qi (Ju Qi) will return to peace.
However, there are five types of this condition that are incurable (see *Zhuzhu Bingyuan* for the five syndromes), but water diseases are the most difficult to treat. One must strictly guard dietary tastes and abstain from sexual activity and excessive play. If these cannot be avoided, relapse after recovery is common. The Classics state: The method for treating water disease is to induce sweating for swelling above the waist, and to promote diuresis for swelling below the waist. This is the most appropriate theory.
However, one must be extremely cautious against using purgatives for swelling and fullness, and must differentiate between Yin and Yang. Yin Water disease presents with a deep and slow pulse, a bluish-white complexion, no irritability or thirst, scanty and clear urine, and frequent loose stools. This is Yin Water, suitable for warm formulas such as Shipi San (Real Spleen Powder) and Fuyuan Dan (Restoring Primordial Pill). Yang Water disease presents with a deep and rapid pulse, a yellowish-red complexion, irritability or thirst, red and scanty urine, and constipation. This is Yang Water, suitable for cooling and neutral medicines such as Shuqiao Yinzi (Dredging Irrigation Decoction) and Yatou Wan (Duck Head Pill).
Furthermore, young people whose blood heat generates sores may develop swelling and fullness, irritability, thirst, and oliguria; this is called Heat Swelling. This corresponds to what the *Suwen* states: "Yang binding results in swelling of the four limbs."