凡泄泻之病，多由水谷不分，故以痢水为上策。然痢水之法，法有不同，如湿胜无寒而
泻者，宜四苓散、小厘清饮之类主之，但欲分其清浊也。如湿挟微寒而泻者，宜五苓散、胃
苓汤之类主之，以微温而痢之也。如湿热在脾，热渴喜冷而泻者，宜大厘清饮、茵陈饮、益
元散之类主之，去其湿热而痢之也。
一、泄泻之病，多见小水不利，水谷分则泻自止，故曰∶治泻不利小水，非其治也。然
小水不利，其因非一，而有可利者，有不可利者，宜详辨之。如湿胜作泻而小水不利者，以
一时水土相乱，并归大肠而然也。有热胜作泻而小水不利者，以火乘阴分，水道闭涩而然也
。有寒泻而小水不利者，以小肠之火受伤，气化无权而然也。有脾虚作泻而小水不利者，以
土不制水，清浊不分而然也。有命门火衰作泻而小水不利者，以真阴亏损，元精枯涸而然也
。凡此皆小水不利之候。然惟暴注新病者可痢，形气强壮者可痢，酒湿过度，口腹不慎者可
利，实热闭涩者可痢，小腹胀满，水道痛急者可痢。又若病久者不可痢，阴不足者不可痢，
脉证多寒者不可痢，形虚气弱者不可痢，口干非渴而不喜冷者不可痢。盖虚寒之泻，本非水
有余，实因火不足；本非水不痢，实因气不行。夫病不因水，而痢则亡阴，泻以火虚，而痢
复伤气，倘不察其所病之本，则未有不愈痢愈虚，而速其危者矣。
凡是泄泻这类疾病，大多是因为水谷不能分别清浊所致，因此治疗上以通利小便为上策。然而，通利小便的方法各不相同：如果是湿气偏盛且没有寒象而导致的泄泻，适宜使用四苓散、小厘清饮等方剂来主治，目的是通过分利清浊来止泻；如果是湿气夹杂轻微寒气而导致的泄泻，适宜使用五苓散、胃苓汤等方剂来主治，通过微微温阳的方法来通利小便；如果是湿热蕴结在脾脏，伴有口渴喜冷饮的泄泻，适宜使用大厘清饮、茵陈饮、益元散等方剂来主治，通过清除湿热的方法来通利小便。
一、泄泻这种疾病，常常表现为小便不通畅，只要让水谷各行其道（即分清泌浊），泄泻自然就会停止，所以说：“治疗泄泻如果不通利小便，就不是正确的治疗方法。”然而，小便不通畅的原因不止一种，有的可以通利，有的不可以通利，需要详细辨别。例如，因湿气偏盛导致泄泻且小便不通畅的，是因为一时之间水土之气混乱，共同归于大肠所致；因热邪偏盛导致泄泻且小便不通畅的，是因为火热之邪侵犯阴分，导致水道闭塞涩滞所致；因寒性泄泻且小便不通畅的，是因为小肠之火受损，气化功能无权所致；因脾气虚弱导致泄泻且小便不通畅的，是因为土气不能制约水湿，导致清浊不分所致；因命门火衰导致泄泻且小便不通畅的，是因为真阴亏损，元精枯竭所致。以上这些都是小便不通畅的情况。但是，只有那些发病急骤、病程短的新病患者可以通利小便，体质强壮的人可以通利小便，因饮酒过度或饮食不慎导致者可以通利小便，实热闭涩者可以通利小便，小腹胀满、尿道疼痛急迫者可以通利小便。反之，如果是久病者不可通利小便，阴液不足者不可通利小便，脉象和证候多属寒者不可通利小便，形体虚弱、正气不足者不可通利小便，口干但不渴且不喜冷饮者不可通利小便。这是因为虚寒性质的泄泻，本来并不是水湿有余，实际上是因为阳气不足；本来不是水道不通，实际上是气机运行不畅。如果疾病并非由水湿引起，却强行通利小便，就会耗伤阴液；如果泄泻是由于火（阳）虚引起，却再次通利小便，就会进一步损伤正气。如果不考察疾病的根本原因，那么没有不出现越通利小便身体越虚弱，从而加速病情危重情况的了。
In cases of diarrhea, the pathology often stems from the failure to separate clear and turbid substances within the ingested food and fluids. Therefore, promoting urination is considered the superior therapeutic strategy. However, the methods for promoting urination vary according to the specific syndrome. For diarrhea caused by dampness predominance without cold signs, formulas such as Siling San (Four-Ingredient Powder) or Xiaoli Qingyin (Minor Clearing Decoction) are appropriate, aiming to separate clear from turbid. For diarrhea accompanied by slight cold due to dampness, formulas such as Wuling San (Five-Ingredient Powder) or Weiling Tang (Stomach-Lining Decoction) are suitable, utilizing mild warming properties to promote urination. For diarrhea associated with damp-heat in the spleen, characterized by thirst and a preference for cold drinks, formulas such as Dali Qingyin (Major Clearing Decoction), Yincheng Yin (Artemisia Capillaris Drink), or Yiyuan San (Benefit-Origin Powder) are indicated, aiming to eliminate damp-heat through diuresis.
1. Diarrhea frequently presents with difficult or scanty urination. Once the separation of water and grain is restored, the diarrhea naturally ceases. Hence, it is stated: "Treating diarrhea without promoting urination is not the correct approach." However, the causes of difficult urination are diverse; some conditions allow for diuresis, while others contraindicate it, necessitating careful differentiation.
Diarrhea with difficult urination due to dampness predominance arises from the chaotic mixing of water and earth qi, which converges into the large intestine.
Diarrhea with difficult urination due to heat predominance arises from fire invading the yin aspect, causing obstruction and涩滞 (astringency/stagnation) in the water passages.
Cold-type diarrhea with difficult urination arises from injury to the fire of the small intestine, resulting in powerless qi transformation.
Spleen-deficiency type diarrhea with difficult urination arises from earth failing to control water, leading to the confusion of clear and turbid.
Mingmen fire decline type diarrhea with difficult urination arises from depletion of true yin and exhaustion of primordial essence.
These are all manifestations of difficult urination. However, diuresis is only indicated for acute onset and new diseases, patients with strong constitution and qi, those suffering from excessive alcohol intake or dietary indiscretion, cases of excess heat with closure and stagnation, and instances where the lower abdomen is distended with painful and urgent urinary difficulty.
Conversely, diuresis is contraindicated for chronic diseases, patients with insufficient yin, cases presenting predominantly with cold pulse and symptoms, patients with weak physique and deficient qi, and those with dry mouth but no thirst who do not prefer cold drinks. This is because diarrhea of deficiency-cold nature is not due to an excess of water, but rather a deficiency of fire (yang); it is not that the water passages are blocked, but that qi movement is impaired. If the disease is not caused by water retention, forcing diuresis will deplete yin. If diarrhea is caused by fire (yang) deficiency, further diuresis will damage qi. If the root cause of the disease is not investigated, the result will inevitably be that the more one promotes urination, the weaker the patient becomes, thereby accelerating critical danger.