仲景曰∶若不宜下而便攻之，内虚热入，协热遂痢，烦躁，诸变不可胜数，轻者困笃，重者必
死矣。太阳病二三日，不能卧，反下之，若痢止，必作结胸。未止者，四日复下之，此作协热痢也
。太阳病，外证未除，而数下之，遂协热而痢，痢下不止，心下痞硬，表里不解者，桂枝人参汤主
之。阳明少阳合病，若脉数不解，而下不止，必协热而便脓血也。
按∶此四条乃皆言表证未除而误下之，因致外热未退，内复作痢，故云协热下痢，此一热字，
乃言表热也，非言内热也。夫协者，协同之协，非挟藏之挟，即表里俱病之谓，故治此者，止有桂
枝人参汤一方，其义显然可见。即如成无己《明理论》曰∶表邪传里，里虚协热则痢，乃亦以表邪
为言也。奈何后学不明此义，止因协热二字，每每以表作里，以寒作热，但见作痢者，无论表里虚
实，即认为内热，便云协热下痢。且近有不必误下，而妄用芩连治表热者，表证得寒，热愈不退，
乃致下痢，或脾胃素弱，逢寒即泄者，皆是此证。既见下痢，益云协热，其谬孰甚，独不观仲景桂
枝人参汤，岂治内热之剂乎？寒热倒施，杀人多矣，予因特表于此。
凡伤寒小便清者，病不在里，仍在表也，当解表发汗。小便利者，病不在气分，而在血分，以
小水由于气
化也。
阳盛则欲衄，阴虚小便难。
凡病伤寒而小水利者多吉，以内邪不甚也。
仲景曰∶阳明病，汗出多而渴者，不可与猪苓汤，以汗多必胃燥，故不可复利小水也。
《论》曰∶湿家之为病，一身尽痛，发热，身色如熏黄，其人但头汗出，背强，欲得被覆向火
，舌上如苔者，以丹田有热，胸中有寒，渴欲得水，而不能饮，此湿痹之候。其人小便不利，大便
反快者，但当利其小便。
凡伤寒表证未除，病在阳分者，不可即利小便。盖走其津液，取汗愈难，且恐大便干结也。
张仲景说：如果病情不适宜使用攻下法却强行攻下，会导致体内正气虚弱、热邪内陷，从而引发协热下痢（表证未解兼见热性腹泻），出现烦躁不安等症状，各种变证数不胜数，轻者病情加重陷入危笃，重者必然死亡。太阳病发病两三天，患者无法平卧，此时若误用攻下法，如果腹泻停止，必定形成结胸（痰水互结于胸膈的病症）；如果腹泻未止，到了第四天再次攻下，这就形成了协热下痢。太阳病，体表的证候尚未解除，却多次使用攻下法，导致表热与里热相合而引发腹泻，腹泻不止，胃脘部痞塞胀硬，表证和里证均未解除，应当用桂枝人参汤主治。阳明病与少阳病合病，如果脉象数急不退，且腹泻不止，必然会因协热而导致大便脓血。
按语：以上四条论述都是讲表证未除而误用攻下法，导致外部的热邪未退，内部又发生腹泻，所以称为“协热下痢”。这里的“热”字，指的是表热，而不是内热。“协”是协同的意思，不是夹杂的意思，即指表里同时患病。因此，治疗这类病症，只有桂枝人参汤这一方剂，其中的道理显而易见。就像成无己在《明理论》中所说：“表邪传入体内，因里气虚弱协同热邪而致痢”，也是以表邪来论述的。可惜后世学者不明白这个义理，仅仅因为“协热”二字，常常把表证当作里证，把寒证当作热证，只要见到腹泻，无论表里虚实，就认为是内热，便说是协热下痢。而且近来有人即使没有误用攻下法，也胡乱使用黄芩、黄连来治疗表热，导致表证遇寒后热邪更加不退，反而引起腹泻；或者是脾胃素来虚弱，遇到寒凉食物或药物就泄泻的，都属于这种证候。既然已经见到下痢，更说是协热下痢，这种谬误多么严重！难道没看过张仲景的桂枝人参汤吗？那难道是治疗内热的方剂吗？寒热治法颠倒施用，害死了许多人，我特意在此阐明这一点。
凡是伤寒病患者小便清长的，说明病不在里，仍在体表，应当采用解表发汗的方法。小便通利的，说明病不在气分，而在血分，因为小便的排泄依赖于气化功能。
阳气亢盛则容易发生鼻出血，阴液亏虚则小便困难。
凡是患伤寒病而小便通利的，大多预后良好，因为体内的邪气不严重。
张仲景说：阳明病，出汗多且口渴的，不可给予猪苓汤，因为汗出过多必然导致胃中干燥，所以不能再利小便以进一步损伤津液。
《内经》相关论述说：患有湿病的病人，全身疼痛，发热，身体颜色像被烟熏过的黄色，患者只有头部出汗，背部僵硬，想要盖被子靠近火源取暖，舌苔白腻，这是因为丹田（下焦）有热，胸中有寒，口渴想喝水，但又喝不下去，这是湿痹的症状。如果患者小便不利，大便反而通畅快速的，只应当采用利小便的方法治疗。
凡是伤寒表证未除，病在阳分的，不可以立即使用利小便的方法。因为利小便会耗伤津液，使得取汗解表更加困难，并且恐怕会导致大便干结。
Zhang Zhongjing stated: If purgation is inappropriately applied when it is contraindicated, the interior becomes deficient and heat enters, leading to *xie re li* (diarrhea with accompanying exterior heat), restlessness, and numerous other complications; mild cases become critical, while severe cases result in death. In Taiyang disease, if for two or three days the patient cannot lie down and purgation is wrongly applied, if the diarrhea stops, *Jie Xiong* (chest binding syndrome) will inevitably develop; if the diarrhea does not stop, and purgation is applied again on the fourth day, this constitutes *xie re li*. In Taiyang disease, if the exterior symptoms remain unresolved but multiple purgations are used, heat from the exterior combines with the interior to cause diarrhea that does not cease, accompanied by epigastric fullness and hardness, where both exterior and interior conditions remain unresolved; Guizhi Renshen Tang (Cinnamon Twig and Ginseng Decoction) should be administered. In combined Yangming and Shaoyang diseases, if the pulse remains rapid and diarrhea persists, heat will combine to cause pus and blood in the stool.
Commentary: These four passages all discuss situations where the exterior syndrome remains unresolved but purgation is mistakenly used, causing external heat to persist while internal diarrhea develops; hence it is called "xie re xia li" (diarrhea with accompanying heat). The character "re" (heat) here refers to exterior heat, not interior heat. The character "xie" (accompanying/combining) means coordination, not夾 (clinging/mixing); it signifies that both exterior and interior are diseased. Therefore, for treating such conditions, there is only one formula, Guizhi Renshen Tang, making its rationale obvious. As Cheng Wuji stated in *Ming Li Lun*: "When exterior pathogens transmit to the interior, interior deficiency accompanies heat to cause diarrhea," he also spoke of exterior pathogens. Alas, later scholars fail to understand this meaning; merely because of the term "xie re," they often mistake exterior for interior, and cold for heat. Whenever diarrhea is seen, regardless of exterior-interior or deficiency-excess patterns, it is considered interior heat and labeled as "xie re xia li." Moreover, recently some practitioners, even without prior mistaken purgation, recklessly use Huangqin (Scutellariae Radix) and Lianzi (Lotus Plumule) to treat exterior heat; when exterior syndromes encounter cold, the heat fails to dissipate, leading to diarrhea. Or, those with inherently weak spleen and stomach who experience loose stools upon exposure to cold are also suffering from this syndrome. Upon seeing diarrhea, one further claims it is "xie re"; how egregious is this error! Have they not observed Zhang Zhongjing's Guizhi Renshen Tang? Is that a formula for treating interior heat? Reversing cold and heat treatments has killed many people. I specifically highlight this point.
In general, if urine is clear in patients with Shanghan (Cold Damage), the disease is not in the interior but remains in the exterior; exterior resolution through sweating should be employed. If urination is smooth, the disease is not in the Qi level but in the Blood level, as urination depends on Qi transformation.
Exuberant Yang leads to epistaxis; Yin deficiency leads to difficult urination.
In general, for Shanghan patients with smooth urination, the prognosis is mostly auspicious because the interior pathogenic factor is not severe.
Zhang Zhongjing said: In Yangming disease, if there is profuse sweating and thirst, Zhu Ling Tang (Polyporus Decoction) must not be given, because excessive sweating causes stomach dryness, so one must not further promote diuresis.
The Treatise states: For patients with dampness diseases, there is generalized body pain, fever, a sallow complexion resembling smoke staining, head sweat only, stiffness in the back, a desire to cover oneself and face fire, and a tongue coating resembling moss. This is due to heat in the Dantian (lower jiao) and cold in the chest, thirst with an inability to drink water; this is a presentation of Shi Bi (dampness bi-syndrome). If the patient has difficult urination but frequent, loose stools, treatment should focus solely on promoting diuresis.
In general, if the exterior syndrome of Shanghan is not yet resolved and the disease is in the Yang level, diuretics should not be immediately used. Depleting body fluids makes obtaining sweat more difficult and may lead to dry stools.