伤寒身热固不可下，疮疹热亦在表，尤不可转下者，盖热毒已在表故也。《活人书》云
∶小儿身热耳冷，尻冷咳嗽，辄用利药，必毒瓦斯入里，则杀人。盖热在表，则表实而里虚，
故身虽热，里无可下证，而便下之，则里无阳以应表，至于陷伏而死者多矣。大抵疮疹血气
顺，脾胃温，则易发；若里无热，而误于疏转，则令气弱血涩脾冷，荣卫无以运化，而毒瓦斯
难泄，立见危殆，尤当审谛。又况小儿鼻塞唇焦，内伏热也。脉细面色萎黄，或青色，皮肤
又慢，口吐清涎者，此误下证也。或服凉药太过，或里无热壅滞，则不可下也。
夫疮疹伤寒风热伤食诸证，身有热者，如大便四五日或六七日不通者，须用少药令润过
，非取峻快之意，亦有外证参之，须仔细辨认为宜。如仲景云∶阳结阴结，大便秘者，至十
四日十七日方剧。苟若至十四日十七日，因有他病损耗津液，而无结粪，腹不胀，不里急后
重，则不可攻之，盖肠无结粪故也。今言六七日令润过，气升降则身热者，不生他疾，缘小
儿纯阳，身热而大便不通者易实，大便自利者易虚，易生他疾，当调令大便如常，最为候脏
腑虚实之要法也。虽然大便秘非一证，有风秘，有气秘，有热秘虚秘冷秘，用药当细辨也，
且人能食，大便不通，结涩如下栗块者，风秘也；烦躁引饮，小便赤而大便秘，腋下手掌心
有汗者，热秘也；腹胀肠中虚鸣，胸胁不利，腰腹引痛者，气秘也；呕吐清水，不能食，面
青而瘦，冷秘也；或久病患不能乳食，腹不胀，不里急后重，虽久不大便者，虚秘也。凡此
五秘者，当随证治之。若大便如常，且不可以冷药与服，恐冰住胃脉，荣卫不行，则疮疹亦
不出矣，又有患至五七日，自然泻者，须用与理中丸等温肠胃药，若泻住即止后服，亦不下
过热，此是当下当温之证。又有疮疹出正盛，喘粗气急，腹胀小便赤涩，手掌心并腋下有汗
，或睡中谵语，大便不通者，用四顺饮子，得气通喘定，腹不胀则已之，下之疮红快者，更
不须通也。
伤寒病中，身体发热本来就不可以使用泻下法，疮疹（天花、麻疹等出疹性传染病）的热邪也在体表，尤其不可使用泻下法，这是因为热毒已经在体表的原因。《活人书》说：小儿身体发热但耳朵冷，臀部冷且咳嗽，如果随意使用通便药物，必然导致毒瓦斯侵入体内，从而致死。因为热邪在体表，则体表实而体内虚，所以虽然身体发热，但体内没有可以泻下的证候，如果强行泻下，则体内阳气不足以呼应体表的邪气，导致邪气内陷伏匿而死的情况很多。大抵疮疹若气血顺畅，脾胃温暖，则容易发出；如果体内无热，却误用了疏利转导的药物，就会导致气弱血涩、脾脏寒冷，营卫之气无法运化，毒瓦斯难以排泄，立刻出现危险，尤其应当仔细审察。况且小儿鼻塞、嘴唇焦干，是内有伏热的表现。脉象细弱、面色萎黄或发青，皮肤松弛无力，口吐清稀涎沫的，这是误用泻下法的证候。或者服用寒凉药物太过，或者体内没有热邪壅滞，则不可以使用泻下法。
至于疮疹因伤风、伤风热、伤食等各种证候，身体有发热的，如果大便四五天或六七天不通畅，必须使用少量药物使其润通，并非追求峻猛快速的意图，还要结合外部证候参酌，必须仔细辨认为宜。如张仲景所说：阳结和阴结导致大便秘结的，到了十四天或十七天才加重。如果到了十四天或十七天，因为其他疾病损耗津液，而没有燥结的粪便，腹部不胀满，没有里急后重感，则不可以攻下，因为肠道没有燥结粪便的缘故。现在说六七天令其润通，气机升降正常则身体发热不会引发其他疾病，因为小儿属于纯阳之体，身体发热而大便不通容易形成实证，大便自利的容易形成虚证，容易产生其他疾病，应当调理使大便恢复正常，这是候察脏腑虚实的重要方法。虽然大便秘结不止一种证候，有风秘、气秘、热秘、虚秘、冷秘，用药应当仔细辨别。而且人能进食，大便不通，干燥结块像栗子一样的，是风秘；烦躁多饮，小便赤红且大便秘结，腋下和手心出汗的，是热秘；腹胀肠中虚鸣，胸胁不利，腰腹牵引疼痛的，是气秘；呕吐清水，不能进食，面色青且消瘦的，是冷秘；或者久病不能乳食，腹部不胀，没有里急后重感，即使很久不大便的，是虚秘。凡此五种秘结，应当随证治疗。如果大便正常，且不可以给予寒凉药物，恐怕会使胃脉凝滞，营卫运行不畅，则疮疹也无法发出。又有患病到五七天，自然腹泻的，必须使用理中丸等温补肠胃的药物，如果腹泻停止就停止后续服药，这也不是过用泻下，这是应当温补的证候。又有疮疹发出正盛，气喘粗重气急，腹胀小便赤涩，手掌心和腋下出汗，或者睡中说胡话，大便不通的，使用四顺饮子，得气通畅喘息安定，腹部不胀满就好了，如果泻下后疮疹红润畅快，更不需要再通利了。
In the context of Shanghan (Cold Damage) disease, where the body is hot, purgation (using laxatives to clear heat and accumulation) is inherently contraindicated. Similarly, for Chu Zhen (exanthematous diseases such as smallpox and measles), the heat pathogen remains at the exterior level, making purgation especially inadvisable; this is because the heat toxin has already manifested at the exterior. The *Huoren Shu* (Book of Living People) states: "If a child presents with fever but cold ears and cold buttocks, accompanied by coughing, and one indiscriminately uses purgative medicines, it will inevitably cause toxic factors to penetrate inward, leading to death." This is because when heat is at the exterior, the exterior is excess while the interior is deficient. Thus, although the body is hot, there are no signs of interior excess requiring purgation. If purgation is forced, the interior Yang Qi becomes insufficient to support the exterior against the pathogen, often resulting in the collapse and internal entrapment of the pathogen, leading to death. Generally, if the Qi and Blood flow smoothly and the Spleen and Stomach are warm during exanthematous diseases, eruption occurs easily. Conversely, if there is no interior heat but one mistakenly uses draining or purgative methods, it leads to weak Qi, stagnant Blood, and cold Spleen. The Ying and Wei (Nutritive and Defensive Qi) lose their ability to transform and transport, making it difficult to expel the toxic factors, immediately bringing danger. Therefore, careful examination is paramount. Furthermore, nasal congestion and dry, cracked lips in children indicate latent interior heat. A fine pulse, sallow or bluish complexion, flaccid skin, and spitting of clear saliva are signs of erroneous purgation. If excessive cold-natured medicines have been taken, or if there is no interior heat stagnation, purgation must not be used.
Regarding various syndromes of exanthematous diseases caused by Wind-Cold, Wind-Heat, or Food Retention, if the patient has fever and has not had a bowel movement for four to six or seven days, mild laxatives should be used to moisten the intestines, not to achieve a drastic purgative effect. External symptoms must also be considered, and careful differentiation is appropriate. As Zhang Zhongjing stated: In cases of Yang Knotting or Yin Knotting causing constipation, symptoms may worsen on the fourteenth or seventeenth day. However, if by the fourteenth or seventeenth day, fluid depletion from other illnesses results in no hardened feces, and the abdomen is not distended nor is there tenesmus (straining without relief), then attack/purgation is contraindicated because there is no hardened stool in the intestines. The current text suggests moistening after six or seven days; if Qi ascends and descends normally, fever will not give rise to other diseases. Since children are of "Pure Yang" constitution, fever with constipation tends toward Excess, while spontaneous diarrhea tends toward Deficiency, both predisposing them to other ailments. Therefore, regulating bowel movements to normalcy is a crucial method for assessing the Deficiency or Excess of the Zang-Fu organs. Although constipation is not a single syndrome—there are Wind Constipation, Qi Constipation, Heat Constipation, Deficiency Constipation, and Cold Constipation—the prescription of medicines requires detailed differentiation. If the patient can eat but suffers from constipation with dry stools resembling chestnut pieces, it is Wind Constipation; if there is irritability, thirst, red urine, constipation, and sweating in the axillae and palms, it is Heat Constipation; if there is abdominal distension, borborygmus (rumbling in the intestines), chest and hypochondriac discomfort, and radiating pain in the waist and abdomen, it is Qi Constipation; if there is vomiting of clear water, anorexia, bluish complexion, and emaciation, it is Cold Constipation; if a chronically ill patient cannot take milk or food, has no abdominal distension or tenesmus, yet has not had a bowel movement for a long time, it is Deficiency Constipation. All five types of constipation should be treated according to their specific syndromes. If bowel movements are normal, cold-natured medicines should not be administered, lest they freeze the Stomach meridians and obstruct the circulation of Ying and Wei, thereby preventing the eruption of exanthems. Additionally, if a patient naturally experiences diarrhea between the fifth and seventh days of illness, warming agents for the middle Jiao, such as Lizhong Wan (Regulate the Middle Pill), should be used. Once the diarrhea stops, subsequent administration should cease; this is not an overuse of purgation but rather a case requiring warming therapy. Finally, if exanthems are erupting vigorously, accompanied by coarse breathing, shortness of breath, abdominal distension, dark and scanty urination, sweating in the palms and axillae, somnolence with delirium, and constipation, Sixun Yinzi (Four-Obedience Decoction) should be used. When Qi flows freely, panting subsides, and abdominal distension resolves, the condition improves. If purgation results in bright red and smooth eruption of the exanthems, further purgation is unnecessary.