凡伤寒热病，下后热不退，下证尚在者，再三下之以热退为度。虽热退尚未痊愈者，随证调之。
凡下之前后，或大汗将出，或大汗已出（俗言好汗，是言大汗），或汗后烦渴及诸吐泻杂病，一切烦渴者，
须以细细饮之。渴未止者，频频时与，但不可过多，以成留饮不散者也（留饮，一名水蓄；经曰积饮）。
夫留饮，谓水液留积蓄聚于内，而不湿润传化者也。夫肠胃燥热太甚，则结滞而气液不能宣通，
故虽饮而难以止其烦渴也。若以顿饮过多，则水湿过极，而肠胃燥热怫郁，转以加其水湿痞闭，故成留饮，
而心腹满痛，或为吐泻也。
设若不与饮之，则燥热转甚，危而死矣。
夫肠胃之燥、湿，犹地旱、涝适当其宜，皆不可过与不及。凡治病之道，以调六气阴阳，使无偏倾，
各守其常，平和而矣。嗟夫！世俗或以妄为冷水、寒药水损脾肾，隔却大汗。但令中外俱热而欲望其作大
汗者；或大汗欲出，肠胃燥热烦渴；及汗已出及虑水却大汗，不与水者；或气弱久虚，烦渴者；
或吐泻烦渴者；或产妇烦渴，皆以妄为气虚，不可饮水也。此乃未知古人云渴欲饮水为热在里也。若夫正
气既衰，邪热燥甚而烦渴者，若非水液寒药滋养，救其残阴，退其邪热，则阳热暴甚而为害速矣。况不与
水而反以大毒热药燥之，宁无损者耶。且如酒之体者，水也，比之饮水，则过能多饮，而旋能消散之外，转
能发于渴者，以其苦热养于心火，则阳盛阴衰，而燥去水湿之体，故旋能消散而善多饮水也。其酒之善多
饮者，以其酒之热毒，若非复以水体胜之；则亦少饮疾醉者，强以饮多，则燥热太甚而多生病也。然酒力
之热，善消水体，复制酒力，以其热力多于水体，故饮多即热醉而燥尽水体，势力尚在，则燥热烦渴而
病于酒也。然酒之热耗尽水体之外，尚能燥热烦渴为病，况病于燥热太甚，而烦渴，及不与水者，岂不
知其害耶。凡燥热烦渴者，肠胃易为怫郁，常以退热、开结、散水、润燥之药调之，免致燥热太甚，
则怫郁以成留饮。虽多饮，亦不止其肠胃脏腑之燥热烦渴；而或肠胃之内，湿甚以成吐泻也，凉膈、白虎、
五苓及桂苓甘露散之类，随证以调之也。或成留饮诸病者，随证燥之。
宜小青龙汤、五苓、桂苓甘露、黄连解毒汤、小陷胸、大承气之类证本方论中。
凡是伤寒热病，经过泻下治疗后发热仍未消退，且里实热证（指邪热与积滞互结于肠胃的证候）依然存在的情况，可以反复使用泻下法，直到热退为止。即使热退后尚未完全痊愈，也要根据具体证候进行调理。
在泻下治疗的前后，或者大汗即将发出、大汗已经发出（俗语所说的“好汗”，指的是大汗），以及汗后出现烦躁口渴和各种呕吐腹泻等杂病，所有出现烦躁口渴症状的，都必须让患者少量多次地饮水。如果口渴未止，应频繁给予饮水，但不可过量，以免形成水饮停聚不散的病证（留饮，又称水蓄；《内经》称为积饮）。所谓留饮，是指水液停留积聚在体内，不能正常滋润和传导代谢。如果肠胃燥热过于严重，就会导致气机结滞，津液无法宣通，因此虽然饮水也难以解除其烦躁口渴的症状。如果一次性大量饮水，会导致水湿过盛，而肠胃原有的燥热被郁遏，反而加重了水湿痞塞闭阻的情况，从而形成留饮，导致心腹部胀满疼痛，或者出现呕吐腹泻。
假设不给予饮水，那么燥热会更加严重，甚至导致危重死亡。
肠胃的燥与湿，就像土地的干旱与洪涝一样，应当适中，既不能过多也不能不足。大凡治病的原则，在于调和六气阴阳，使其没有偏颇倾斜，各自保持常态，达到平和的状态。唉！世俗之人有时错误地认为冷水、寒性药水会损伤脾肾，阻碍大汗的发出。他们只希望身体内外都发热，却指望由此能发出大汗；或者在大汗即将发出时，遇到肠胃燥热烦躁口渴；或者大汗已出，又担心喝水会遏制大汗，不给患者饮水；或者患者气弱久虚而烦躁口渴；或者呕吐腹泻而烦躁口渴；或者产妇烦躁口渴，这些都错误地认为是气虚，不可以饮水。这完全是不知道古人所说“口渴想喝水”是因为热邪在里的缘故。如果正气已经衰弱，邪热燥盛而导致烦躁口渴，如果不是用水液和寒凉药物来滋养，挽救残存的阴液，退去邪热，那么阳热就会突然亢盛而迅速造成危害。何况不给水喝，反而用大毒性的热药来燥化它，难道不会造成伤害吗？这就好比酒的本质是水，比起直接饮水，酒能让人多喝，并且能迅速消散，转而引发口渴，是因为酒味苦热，助长心火，导致阳盛阴衰，使身体失去水的湿润特性，所以能迅速消散并善于让人多饮水。酒之所以能让人多饮，是因为酒的热毒，如果不是再用大量的水来克制它，那么稍微饮酒就会醉酒；强行多喝，就会导致燥热太甚而产生多种疾病。然而酒力的热性，善于消耗体内的水液，再加上酒力本身的热力多于水体的滋润力，所以喝多了就会因热而醉，耗尽体内的水液，势力仍在，就会导致燥热烦躁口渴，患上酒病。既然酒的热性耗尽了水液之外，还能因为燥热烦躁口渴而致病，何况是患病于燥热太甚，出现烦躁口渴，却不给饮水的人，难道不知道其中的害处吗？凡是燥热烦躁口渴的，肠胃容易郁结阻滞，常用清热、开结、利水、润燥的药物来调理，避免燥热太甚，从而因郁结而形成留饮。即使多喝水，也不能止住肠胃脏腑的燥热烦躁口渴；而如果肠胃内湿气过重，则会形成呕吐腹泻。对于这种情况，可用凉膈散、白虎汤、五苓散及桂苓甘露散等方剂，根据证候进行调理。如果形成了留饮相关的各种病症，则根据证候用燥湿化痰等方法治疗。适宜用小青龙汤、五苓散、桂苓甘露散、黄连解毒汤、小陷胸汤、大承气汤等，具体的证候和方论见各方的论述中。
In cases of Shanghan (Cold Damage) and febrile diseases, if fever persists after purgation and the indications for purgation (referring to the syndrome where pathogenic heat and accumulation interact in the intestines and stomach) remain, the purgative method may be repeated until the fever subsides. Even if the fever has subsided but recovery is not yet complete, treatment should be adjusted according to the specific syndrome.
Before and after purgation, or when profuse sweating is about to occur, or has already occurred (colloquially referred to as "good sweat," meaning profuse sweating), as well as in various miscellaneous diseases involving vomiting, diarrhea, etc., following sweating, all cases presenting with irritability and thirst must have water administered in small, frequent sips. If thirst does not cease, water should be given frequently, but never in excessive amounts, to avoid forming a condition of retained fluid retention that fails to disperse (Retained Fluid Retention, also known as Water Accumulation; the *Classic of Internal Medicine* refers to it as Accumulated Drinking). Retained Fluid Retention refers to water fluids stagnating and accumulating within the body, failing to moisten and transform normally. If intestinal and gastric dryness-heat is excessively severe, it leads to qi mechanism stagnation, preventing the distribution of body fluids; therefore, even with drinking, irritability and thirst cannot be relieved. If water is consumed in large quantities at once, it causes excessive dampness-wetness, while the existing dryness-heat in the intestines and stomach becomes constrained, exacerbating the obstruction caused by dampness-fluids, thus forming Retained Fluid Retention. This results in fullness and pain in the heart and abdomen, or vomiting and diarrhea.
If water is not provided, the dryness-heat will intensify, potentially leading to critical danger and death.
The balance of dryness and wetness in the intestines and stomach is like drought and flood in the land; both extremes are inadmissible. The principle of treating disease lies in harmonizing the Six Qi and Yin-Yang, ensuring no bias or deviation, allowing each to maintain its normal state, thereby achieving harmony. Alas! Laypeople often erroneously believe that cold water or cold-natured fluids damage the Spleen and Kidney and obstruct the emergence of profuse sweating. They desire internal and external heat, hoping this will induce profuse sweating; or when profuse sweating is imminent, encountering intestinal-gastric dryness-heat with irritability and thirst; or after profuse sweating has occurred, fearing that drinking water will suppress the sweating, thus withholding water; or when patients with weak qi and chronic deficiency experience irritability and thirst; or those with vomiting, diarrhea, and irritability/thirst; or postpartum women with irritability and thirst—all these are mistakenly attributed to qi deficiency, deeming water intake contraindicated. This demonstrates ignorance of the ancient teaching that "thirst with desire to drink" indicates heat residing in the interior. If righteous qi is depleted, and pathogenic dryness-heat is severe causing irritability and thirst, without nourishment via water fluids and cold-natured medicines to preserve residual yin and clear pathogenic heat, yang-heat will surge violently, causing rapid harm. Moreover, withholding water while administering highly toxic hot medicines to desiccate the body—would this not cause damage? Consider wine: its substance is water. Compared to plain water, wine allows greater consumption and rapid dispersion, yet induces thirst because its bitter-hot nature supports Heart Fire, leading to excess yang and deficient yin, stripping the body of its moistening quality, thus facilitating rapid dispersion and increased water intake. Wine's capacity for high consumption stems from its hot toxicity; without sufficient water to counteract it, slight consumption leads to drunkenness, while forced overconsumption causes excessive dryness-heat and various illnesses. However, wine's heat consumes bodily fluids; since wine's thermal power exceeds its hydrating power, excessive drinking leads to heat-induced drunkenness, exhausting bodily fluids. With the potency remaining, it causes dryness-heat, irritability, and thirst, resulting in wine-related illness. If wine's heat, having exhausted bodily fluids, still causes illness through dryness-heat and irritability, how much more harmful is it to withhold water from patients suffering from extreme dryness-heat and irritability? In cases of dryness-heat and irritability, the intestines and stomach are prone to constraint and stagnation. Treatment should employ herbs that clear heat, resolve stagnation, promote urination, and moisten dryness to prevent extreme dryness-heat from constraining and forming Retained Fluid Retention. Even with increased water intake, intestinal-gastric dryness-heat and irritability may not cease; conversely, excessive dampness in the intestines and stomach may lead to vomiting and diarrhea. For such conditions, formulas such as Liangge San (Cool the Chest Powder), Baihu Tang (White Tiger Decoction), Wuling San (Five-Ling Powder), and Guiling Ganlu San (Cassia Twig and Poria Sweet Dew Powder) should be used according to the syndrome. For various diseases formed due to Retained Fluid Retention, drying and resolving methods should be applied based on the syndrome. Suitable formulas include Xiao Qinglong Tang (Minor Blue Dragon Decoction), Wuling San, Guiling Ganlu San, Huanglian Jiedu Tang (Coptis Decoction for Resolving Toxicity), Xiao Xianxiong Tang (Minor Trap-the-Chest Decoction), and Dachengqi Tang (Major Order the Qi Decoction); refer to the respective formula discussions for syndrome differentiation and detailed explanations.