《素问》生气通天论曰∶因于湿，首如裹。至真要大论曰∶诸湿肿满，皆属于脾。水热
穴论曰
∶肾何以主水。肾者至阴也，至阴者，盛水也，肺者太阴也，太阴者冬脉也。故其本在肾，
其末在肺。王好古曰∶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。盖脾胃者土也。饮入于胃，游溢精气，下输于脾，脾气
散精，上归于肺，肺者土之子也。肺气盛则清肃令行，通调水道，下输膀胱，而肾者肺之子
，胃之关也。肾气化则二阴通。而三焦者决渎之官，水道出焉。肝肾二经之相火，游行于五
者之间，上承天道之施化，下佐地道之生发，与手厥阴心包为表里，以行诸水，岂有泛溢停
滞之患。若脾胃虚弱，肺无禀受，而气道不通，由是四海闭塞，三焦不泻，日久熏蒸，郁为
湿病。然此为内伤之湿。若外感之症，在天有雨露霜雾之湿，在地有沮洳潮瘴之湿，饮食有
酒浆之湿，衣被有汗液之湿，阳盛则火旺，湿且化热，阴盛则水旺，湿又化寒，风可祛湿，
湿更挟风，燥可除湿，湿还胜燥，内因外因，随经触发，上攻头目，症现各殊。脾湿则多眼
癣眼菌，肺湿则多黄膜，心经湿则多 肉如脂，肝经湿则多星障，黑珠如雾混浊，肾经湿则
瞳神呆钝，色淡昏 无光。治法风药可以胜湿，燥药可以除湿，淡药可以渗湿，泄小便可以
引湿，利大便可以逐湿，吐痰涎可以即湿。湿而有热，苦寒之剂燥之，湿而有寒，辛热之剂
燥之。至于脾肾俱虚，水溢为病，则须培土填精，标本兼治，此东垣脾胃论，所以谆谆于后
天补救也。
《素问·生气通天论》中说：因为受湿邪侵袭，头部感觉像被包裹住一样沉重。《素问·至真要大论》中说：各种湿气引起的肿胀和腹满，都归属于脾脏。《素问·水热穴论》中问道：肾脏为什么主管水液代谢？回答说：肾属于至阴之脏，至阴意味着盛藏水液；肺属于太阴经，太阴对应冬季的脉象。所以水肿病的根本在肾，其标末在肺。王好古说：水液代谢由脾、肺、肾三经共同主导，涉及五脏六腑及十二经脉的各个部分，水液可上行至头面，中行于四肢，下行至腰脚，外达皮肤，内入肌肉，深至筋骨。脾胃属土。饮水进入胃后，精微之气游溢散布，向下输送到脾，脾气将精微物质散播，向上归于肺，肺是“土之子”（五行中火生土，土生金，故肺为脾之子）。肺气旺盛则清肃功能正常，能够疏通调节水道，将水液向下输送到膀胱，而肾是肺之子，也是胃的关口。肾气气化正常，则前后二阴通畅。三焦作为决渎之官，是水道运行的通道。肝肾二经中的相火，游行于五脏之间，上承接天道的施化，下辅助地气的生发，与手厥阴心包经互为表里，以此运行全身水液，怎么会有水液泛溢停滞的祸患呢？如果脾胃虚弱，肺脏得不到滋养，导致气道不通，于是四海闭塞，三焦排泄不利，日久熏蒸郁结，形成湿病。然而这是内伤所致的湿病。如果是外感病症，在天有雨露霜雾之湿，在地有潮湿沼泽瘴气之湿，饮食中有酒浆之湿，衣被上有汗液之湿。阳气盛则火旺，湿邪容易化热；阴气盛则水旺，湿邪又易化寒。风邪可以祛除湿邪，但湿邪更常挟带风邪；燥邪可以消除湿邪，但湿邪往往胜过燥邪。内因和外因随经络触发，向上攻冲头目，症状表现各不相同。脾经有湿则多发生眼癣、眼菌；肺经有湿则多出现黄膜；心经受湿则多长出如脂膏般的息肉；肝经受湿则多出现星障，黑珠（黑睛）如雾般混浊；肾经受湿则瞳神呆钝，颜色淡白昏暗无光。治疗方法：风药可以胜湿，燥药可以除湿，淡味药可以渗湿，通利小便可以引导湿邪排出，通利大便可以驱逐湿邪，催吐痰涎可以即时去除湿邪。湿邪兼有热象，用苦寒药物燥湿清热；湿邪兼有寒象，用辛热药物燥湿散寒。至于脾肾俱虚，水液泛滥成病，则必须培补脾胃、填补肾精，标本兼治，这就是李东垣《脾胃论》中反复强调后天补救的原因。
The *Suwen* (Plain Questions), chapter "Shengqi Tongtian Lun" (Treatise on the Connection between Vital Qi and Heaven), states: "Affected by dampness, the head feels as if wrapped." The *Suwen*, chapter "Zhiyao Da Lun" (Great Treatise on the Most Essential Principles), states: "All dampness-related swelling and fullness belong to the Spleen." The *Suwen*, chapter "Shuire Xuelun" (Treatise on Water-Heat Acupoints), asks: "Why does the Kidney govern water?" It answers: "The Kidney is the organ of extreme Yin; extreme Yin implies the abundance of water. The Lung belongs to the Taiyin (Greater Yin) meridian, and Taiyin corresponds to the winter pulse. Therefore, its root lies in the Kidney, and its branches lie in the Lung." Wang Haogu stated: "Water metabolism is governed by the Spleen, Lung, and Kidney meridians, involving the compartments of the five Zang organs, six Fu organs, and twelve regular meridians. It ascends to the head and face, traverses the four limbs, descends to the waist and feet, reaches the exterior skin, enters the interior muscles, and penetrates the bones and sinews." The Spleen and Stomach belong to Earth. When fluids are ingested into the Stomach, their essence spreads and overflows, descending to be transported by the Spleen. The Spleen scatters these essences upward to return to the Lung. The Lung is the "child of Earth" (in Five Elements theory, Earth generates Metal). When Lung Qi is abundant, its clearing and purifying function proceeds smoothly, regulating and unblocking the water passages, transporting fluids downward to the Bladder. The Kidney is the child of the Lung and the gatekeeper of the Stomach. When Kidney Qi undergoes qi transformation, the two yin openings (urethra and anus) become patent. The Sanjiao (Triple Burner), as the official responsible for irrigation, serves as the pathway for water. The ministerial fire (Xianghuo) of the Liver and Kidney meridians circulates among the five Zang organs, receiving the transformations of Heaven above and assisting the generation of Earth below. It forms an exterior-interior relationship with the Pericardium of Hand-Jueyin to facilitate the movement of all waters. How could there be concerns of flooding or stagnation? However, if the Spleen and Stomach are weak, the Lung receives no nourishment, leading to obstruction of the air pathways. Consequently, the Four Seas become blocked, the Sanjiao fails to drain, and after prolonged steaming and郁 (stagnation), damp disease arises. This, however, is dampness due to internal injury. If it is an external contraction, there is dampness from rain, dew, frost, and fog in the sky; dampness from marshes, tides, and miasmas on the ground; dampness from wine and beverages in diet; and dampness from sweat on clothing and bedding. When Yang is abundant, Fire flares up, and dampness tends to transform into Heat. When Yin is abundant, Water prevails, and dampness tends to transform into Cold. Wind can dispel dampness, yet dampness often carries Wind. Dryness can remove dampness, yet dampness often overcomes dryness. Internal and external causes trigger symptoms along the meridians, attacking the head and eyes upward, presenting diverse manifestations. Dampness in the Spleen meridian often causes eye tinea and fungal growths; dampness in the Lung meridian often presents as yellow membranes; dampness in the Heart meridian often results in fleshy growths like fat; dampness in the Liver meridian often causes star-shaped nebulae, with the black cornea appearing cloudy like mist; dampness in the Kidney meridian leads to dull pupils, pale color, dimness, and lack of luster. Therapeutic methods include: wind herbs to overcome dampness, drying herbs to remove dampness, bland herbs to leach out dampness, promoting urination to guide dampness out, promoting defecation to expel dampness, and inducing vomiting of phlegm to instantly remove dampness. If dampness is accompanied by heat, bitter-cold agents are used to dry and clear it. If dampness is accompanied by cold, acrid-hot agents are used to dry and warm it. In cases where both the Spleen and Kidney are deficient, causing water flooding, one must tonify Earth (Spleen) and fill Essence (Kidney), treating both root and branch. This is why Li Dongyuan's *Piwei Lun* (Treatise on the Spleen and Stomach) earnestly emphasizes the remediation of acquired constitution (Houtian).