太阳下焦有热秘。小腹必满便不利。小便不利反自利。此是抵当血证谛。（大抵热在下焦。小腹必胀满。小便不利。
今反利者。有瘀血也。仲景云。伤寒有热。而小腹满。应小便不利。今反利者。此为血证。当下之。宜抵当丸。又云。
太阳病身黄。其脉沉结。小腹坚。小便不利。为无血。小便自利。其人如狂者。血证谛也。宜抵当汤。）阳明自汗小便结。
忽若利时津液竭。屎虽坚硬不可攻。蜜兑用之斯要诀。（仲景云。阳明病。汗出。若发其汗。小便自利。此为津液内竭。
屎虽坚不可攻之。宜用蜜兑导之。使通。或土瓜根。猪胆汁。皆可以导之也。）又问小便何故数。肾与膀胱虚热作。虚则
故令小便频。热则迟涩相击搏。（虚中有热。小便故难频。并必迟涩也。）自汗不可服桂枝。（仲景云。伤寒脉浮自汗出。
小便数。心烦。微恶寒。脚挛急。服桂枝。得之便厥作。甘草干姜汤主之。）趺阳浮涩是脾约。（仲景云。趺阳脉浮而涩。
浮则胃气强。涩则小便数。浮涩相搏。大便必硬。其脾为约。麻仁丸主之。）胃中不和谵语时。调胃承气宜斟酌。（仲景
云。伤寒脉浮。自汗。小便数。若胃中不和。谵语者。少少与调胃承气汤。）
大便坚硬或不通。柴胡承气可收功。（大柴胡汤。大小承气皆要药也。）亦有不可攻击者。歌在前篇里证中。（前篇里
证歌有不可下者。）寒则溏热则垢。可见阴阳虚实候。岁火不及大寒行。民病骛溏肠胃吼。（素问云。岁火不及。寒乃大
行。民病骛溏者。鸭溏也。）
太阳经下焦有热邪蕴结，导致大便干结难解。此时小腹部必然感到胀满，且排便不畅。如果小便不仅没有不利，反而通利自如，这是抵当汤证（治疗瘀血阻滞的方剂）的确切指征。（大抵而言，热邪位于下焦，小腹部必定出现胀满感，通常伴随小便不利；如今小便反而通利，说明体内存在瘀血。张仲景说：伤寒病伴有发热，且小腹胀满，按理应当小便不利，如今反而通利，这是蓄血证的特征，应当采用攻下法，适宜使用抵当丸。又说：太阳病出现身体发黄，脉象沉而结滞，小腹部坚硬，若小便不利，则无瘀血；若小便自利，且患者出现如狂乱般的症状，则是蓄血证的确切证据，适宜使用抵当汤。）
阳明病表现为自汗出，若小便短涩不通，忽然变得通利，这是因为津液枯竭所致。虽然粪便已经坚硬，但不可使用峻猛攻下的方法，应当使用蜜煎导法（外用通便法），这是关键的要诀。（张仲景说：阳明病，汗出，如果再发汗，导致小便自利，这是体内津液枯竭的表现。虽然粪便坚硬，但不可用内服攻下药，适宜使用蜜栓导引，使大便通畅。或者使用土瓜根、猪胆汁，都可以起到导便的作用。）
又有人问，为什么小便频数？这是由于肾与膀胱的虚热所致。虚损会导致小便频繁，热邪则导致排尿迟滞涩痛，二者相互搏结。（虚中夹热，所以小便困难且频数，并且必然伴有排尿迟涩的感觉。）
对于自汗出的患者，不可服用桂枝汤。（张仲景说：伤寒脉浮，自汗出，小便频数，心烦，轻微恶寒，脚部拘挛急迫，如果误服桂枝汤，会导致四肢厥冷发作，此时应用甘草干姜汤主治。）
趺阳脉呈现浮涩之象，是脾约证（脾阴不足，胃强约束脾津）的表现。（张仲景说：趺阳脉浮而涩，浮代表胃气强盛，涩代表小便频数，浮与涩相搏结，大便必然坚硬，这就是脾约证，由麻仁丸主治。）
胃中不和，时常出现胡言乱语（谵语），应斟酌使用调胃承气汤。（张仲景说：伤寒脉浮，自汗出，小便频数，如果胃中不和，出现谵语，应少量给予调胃承气汤。）
大便坚硬或不通畅，柴胡承气汤可以收效。（大柴胡汤、大承气汤和小承气汤都是重要的药物。）也有不适合攻下的情况，这些内容在之前的“里证歌”篇章中已有记载。（前篇关于里证的歌诀中提到有不可攻下的情况。）寒邪导致大便稀溏，热邪导致排泄物秽浊，由此可以看出阴阳虚实的证候。岁运火气不及，寒气盛行，民众容易患病为鸭溏（水样腹泻）和肠胃鸣响。（《素问》说：岁运火气不及，寒气就会大肆流行，民众易患鸭溏症。）
Heat in the lower jiao of the Taiyang channel causes constipation. The lower abdomen must be full, and defecation is difficult. If urination is not obstructed but rather flows freely, this is a definitive indication for the Didang Blood Syndrome (a syndrome treated with Didang Decoction to resolve blood stasis). (Generally speaking, when heat resides in the lower jiao, the lower abdomen becomes distended, and urination is typically obstructed; if urination is now free, it indicates the presence of blood stasis. Zhang Zhongjing stated: In cold damage with fever and lower abdominal fullness, one should expect obstructed urination; if it is now free, this is a sign of blood accumulation, requiring purgation, preferably with Didang Pill. He also stated: In Taiyang disease, if the body turns yellow, the pulse is deep and knotted, and the lower abdomen is hard, but urination is obstructed, there is no blood stasis; if urination is free and the patient exhibits manic behavior, this is a definitive sign of blood stasis, suitable for treatment with Didang Decoction.)
Yangming disease presents with spontaneous sweating. If urination changes from obstructed to free, it indicates the exhaustion of body fluids. Although the stool is hard, harsh purgatives should not be used; instead, honey suppositories should be employed, which is a crucial principle. (Zhang Zhongjing stated: In Yangming disease with sweating, if further sweating leads to free urination, this indicates internal exhaustion of fluids. Although the stool is hard, internal purgatives are contraindicated; honey suppositories should be used to guide the passage of stool. Alternatively, root of Trichosanthes kirilowii or pig bile can also be used for guidance.)
One may ask why urination is frequent. This is caused by deficient heat in the Kidney and Bladder. Deficiency leads to frequent urination, while heat causes delayed and涩 (obstructed) flow, with both factors interacting. (Deficiency with internal heat results in difficult and frequent urination, accompanied by delayed and涩 sensation.)
For patients with spontaneous sweating, Guizhi Tang (Cinnamon Twig Decoction) should not be administered. (Zhang Zhongjing stated: In cold damage with a floating pulse, spontaneous sweating, frequent urination, mental restlessness, slight aversion to cold, and cramped legs, administering Guizhi Tang will lead to cold limbs; in such cases, Gancao Ganjiang Tang (Licorice and Dried Ginger Decoction) should be used.)
A floating and涩 pulse at the Fuyang position indicates Pi Yue (Spleen Constraint). (Zhang Zhongjing stated: A floating and涩 pulse at the Fuyang position indicates strong Stomach Qi (floating) and frequent urination (涩). The interaction of floating and涩 leads to hard stool, known as Spleen Constraint, treated with Mahuang Wan (Hemp Seed Pill).)
Disorder in the Stomach causing occasional delirium requires careful consideration of Tiaowei Chengqi Tang (Regulate the Stomach and Direct Downward Decoction). (Zhang Zhongjing stated: In cold damage with a floating pulse, spontaneous sweating, and frequent urination, if there is Stomach disorder leading to delirium, small amounts of Tiaowei Chengqi Tang should be given.)
Hard or obstructed stool can be resolved with Chaihu Chengqi Tang (Bupleurum and Direct Downward Decoction). (Da Chaihu Tang (Greater Bupleurum Decoction), Da Chengqi Tang (Greater Direct Downward Decoction), and Xiao Chengqi Tang (Lesser Direct Downward Decoction) are all essential formulas.) There are also cases where purgation is contraindicated, as detailed in the previous chapter on Interior Syndromes. (The previous chapter on Interior Syndromes mentions conditions where downward purgation is forbidden.) Cold leads to loose stools, while heat leads to foul discharge, revealing the patterns of Yin-Yang deficiency and excess. When the annual Fire element is insufficient, Cold dominates, and people suffer from watery diarrhea (wu tang) and intestinal rumbling. (Su Wen states: When the annual Fire element is insufficient, Cold prevails, and people suffer from watery diarrhea.)