仲景曰。太阳病不解。热结膀胱。其人如狂。血自下。下者愈。其
外不解者。尚未可攻。当先解其外。属桂枝汤。外解已。血未下。但少
腹急结者。乃可攻之。宜桃核承气汤。雍曰。小便不利。不可攻也。
又曰。太阳病六七日。表症仍在。脉微而沉。反不结胸。其人发
狂者。以热在下焦。小腹当硬满。而小便自利者。下血乃愈。所以然
者。以太阳随经。瘀热在里故也。宜下之。以抵当汤主之。
又曰。太阳病。身黄。脉沉结。小腹硬满。小便不利者。为无血
也。小便自利。其人如狂者。血证谛也。抵当汤主之。常氏云。小便不
利。无血者。与五苓散。
又曰。伤寒有热。小腹满。应小便不利。今反利者。为有血也。当
下之。不可余药。宜抵当丸。
又曰。阳明症。其人喜忘者。必有蓄血。所以然者。本有久瘀血。
故令喜忘。屎虽硬。大便反易。其色必黑者。宜抵当汤下之。
又曰。病患无表里症。发热七八日。虽脉浮数者。可下之。假令
已下。脉数不解。合热则消谷善饥。至六七日。不大便者。有瘀血。宜
抵当汤。脉经云。若脉数不解。而下不止。必协热而便脓血也。
又曰。少阴病八九日。一身手足尽热者。此热在膀胱。必便血
也。常氏曰。宜用桃核承气汤、芍药地黄汤。雍曰。宜先犀角地黄汤。
又曰。伤寒。热少厥微。指头寒。默默不欲食。烦躁数日。小便利
色白者。此热除也。欲得食。其病可愈。若厥而呕。胸胁烦满者。其后
必便血。常氏云。便血者。可黄芩汤。雍曰。热已除者。畏黄芩。
又曰。淋家不可发汗。发汗必便血。常氏云。可柏皮汤。
又曰。太阳病。以火熏之。不得汗。其人必躁。到经不解。必圊血也。
雍曰。凡病各有轻重。治病用药。亦有轻重。且如瘀血一症。用
抵当汤。根据法如此。不可易也。若其血症轻。或治之早者。亦不须用。
只服犀角地黄汤。血症稍重。及治之瘥迟者。则用桃核承气汤。其重
及治之迟者。方用抵当汤丸。抵当汤丸是十分之药。轻病不宜用也。
用他药仿此。
张仲景说：太阳病（太阳经受邪所致的病证）未解，热邪结聚于膀胱。患者出现神志失常、似狂非狂的症状。若瘀血能自行排出，则病可愈。如果表证仍未解除，尚不可使用攻下法，应当先解除表证，适用桂枝汤（Cinnamon Twig Decoction）。待表证解除后，若瘀血仍未下行，仅表现为少腹部位拘急硬满，此时才可进行攻下治疗，适宜使用桃核承气汤（Peach Kernel Decoction to Inherit the Command）。郭雍认为：若小便不通利，则不可攻下。
又说：太阳病经过六七日，表证依然存在，脉象微而沉，反而没有形成结胸证。患者出现发狂症状，这是因为热邪在下焦。少腹部应当硬满，且小便自利通畅，此时通过泻下瘀血病可痊愈。之所以这样，是因为太阳经邪气随经入里，瘀热蕴结在体内所致。适宜采用攻下法，以抵当汤（Diding Decoction）为主治方剂。
又说：太阳病，身体发黄，脉象沉涩，少腹硬满，若小便不利，说明无瘀血。若小便自利，患者出现似狂非狂的症状，则是瘀血的确诊依据，主治方剂为抵当汤。常氏说：若小便不利且无瘀血者，给予五苓散（Five-Ingredient Powder with Poria）。
又说：伤寒病伴有发热，少腹胀满，本应小便不利，如今反见小便通利，说明有瘀血存在。应当攻下瘀血，不可服用其他药物，适宜使用抵当丸（Diding Pill）。
又说：阳明病（阳明经受邪所致的病证），患者容易健忘，必定有蓄血。之所以如此，是因为原本就有久留的瘀血，所以导致健忘。大便虽然干硬，但排便反而容易，且颜色必定发黑，适宜用抵当汤攻下。
又说：患者既无表证也无里证，发热七八天，即使脉象浮数，也可使用攻下法。假如已经攻下，脉数仍未缓解，热邪与胃气相合则消谷善饥。到了第六七天，若不大便，说明有瘀血，适宜用抵当汤。《脉经》说：若脉数不解，且出现下利不止，必然伴随热邪而排泄脓血。
又说：少阴病（少阴经受邪所致的病证）八九日，全身及手足均发热，这是热邪在膀胱，必定会出现便血。常氏说：适宜使用桃核承气汤、芍药地黄汤（Peony and Rehmannia Decoction）。郭雍说：适宜先用犀角地黄汤（Rhinoceros Horn and Rehmannia Decoction）。
又说：伤寒病，热势轻微，四肢厥冷轻微，仅指尖发凉，神情沉默不欲饮食，烦躁数日，若小便通利且颜色清白，说明热邪已除，想要进食，疾病即可痊愈。若出现四肢厥冷伴呕吐，胸胁烦闷胀满，其后必定出现便血。常氏说：便血者，可用黄芩汤（Scutellaria Decoction）。郭雍说：热邪已除者，畏惧使用黄芩。
又说：淋家（患有淋证的病人）不可发汗，发汗必定导致便血。常氏说：可用柏皮汤（Phellodendron Decoction）。
又说：太阳病，用火熏法治疗，未能出汗，患者必定躁扰不安。若到该病传变周期仍未解除，必定出现圊血（排便出血）。
郭雍说：凡是疾病各有轻重，治病用药也有轻重之分。例如瘀血这一病症，使用抵当汤，依据法规应当如此，不可更改。若血症较轻，或治疗及时者，也不须使用抵当汤，只需服用犀角地黄汤。血症稍重，以及治疗延误者，则使用桃核承气汤。病情严重及治疗延误者，才使用抵当汤或抵当丸。抵当汤和抵当丸是峻猛之药，轻症不宜使用。使用其他药物也仿照此理。
Zhang Zhongjing stated: When Taiyang disease (disease of the Taiyang channel) is not resolved, heat accumulates in the Bladder. The patient exhibits a manic-like state. If blood discharges spontaneously, the disease will heal. If the exterior syndrome remains unresolved, attack methods should not yet be used; instead, the exterior should first be released, using Guizhi Tang (Cinnamon Twig Decoction). Once the exterior is resolved, if the blood has not discharged but there is only urgency and binding in the lower abdomen, then an attack method may be employed, suitable for Taohao Chengqi Tang (Peach Kernel Decoction to Inherit the Command). Guo Yong noted: If urination is difficult, one must not attack.
He also said: In Taiyang disease after six or seven days, if the exterior syndrome persists, the pulse is faint and deep, and contrary to expectations, Jie Xiong syndrome (chest binding syndrome) does not form, while the patient goes mad, this is because heat is in the Lower Jiao. The lower abdomen should be hard and full, and urination is free and clear. Discharging blood will lead to recovery. This occurs because the Taiyang pathogen follows the channels into the interior, where stasis and heat reside within. An attack method is suitable, primarily using Didang Tang (Diding Decoction).
He also said: In Taiyang disease, if the body is yellow, the pulse is deep and choppy, and the lower abdomen is hard and full, but urination is difficult, this indicates no blood stasis. If urination is free and clear, and the patient exhibits a manic-like state, this confirms the diagnosis of blood stasis, treated primarily with Didang Tang (Diding Decoction). Chang Shi stated: For those with difficult urination and no blood stasis, provide Wuling San (Five-Ingredient Powder with Poria).
He also said: In Shanghan (cold damage) with fever and a full lower abdomen, urination should be difficult; if it is now free, it indicates blood stasis. One should purge, avoiding other medicines, and use Didang Wan (Diding Pill).
He also said: In Yangming disease (disease of the Yangming channel), if the patient suffers from forgetfulness, there must be accumulated blood. This is because long-standing blood stasis exists, causing forgetfulness. Although the stool is hard, defecation is surprisingly easy, and the color must be black; treat by purging with Didang Tang (Diding Decoction).
He also said: If a patient has neither exterior nor interior syndromes but has had fever for seven or eight days, even if the pulse is floating and rapid, one may use an attack method. Suppose purging has already been performed, but the rapid pulse remains unresolved; combined heat causes efficient digestion and frequent hunger. By the sixth or seventh day, if there is no bowel movement, blood stasis is present, suitable for Didang Tang (Diding Decoction). Mai Jing states: If the rapid pulse remains unresolved and diarrhea ensues, heat will surely accompany the discharge of pus and blood.
He also said: In Shaoyin disease (disease of the Shaoyin channel) after eight or nine days, if the whole body and hands and feet are hot, this indicates heat in the Bladder, leading to hematochezia (blood in stool). Chang Shi said: Use Taohao Chengqi Tang (Peach Kernel Decoction to Inherit the Command) or Shaoyao Dihuang Tang (Peony and Rehmannia Decoction). Guo Yong said: Use Xijiao Dihuang Tang (Rhinoceros Horn and Rehmannia Decoction) first.
He also said: In Shanghan, with slight heat and mild cold limbs, only the fingertips are cold, silence prevails, and there is no desire to eat. After several days of irritability, if urination is free and white in color, the heat has cleared; desire to eat indicates recovery. If there is cold limbs accompanied by vomiting and chest/hypochondriac fullness and irritability, hematochezia will follow later. Chang Shi said: For hematochezia, Huangqin Tang (Scutellaria Decoction) can be used. Guo Yong said: For those whose heat has cleared, one fears using Huangqin (Scutellariae Radix).
He also said: Linjia (patients with strangury) must not undergo sweating therapy; sweating will inevitably cause hematochezia. Chang Shi said: Bopi Tang (Phellodendron Decoction) can be used.
He also said: In Taiyang disease, if fire moxibustion/fumigation is applied and sweat cannot be obtained, the patient will become agitated. If the disease cycle passes without resolution, Qingxue (defecating blood) will occur.
Guo Yong stated: All diseases have varying degrees of severity, and medicinal treatment must match this gravity. Regarding blood stasis, using Didang Tang (Diding Decoction) follows standard protocol and should not be altered. If the blood syndrome is mild or treated early, Didang Tang is unnecessary; simply服用 Xijiao Dihuang Tang (Rhinoceros Horn and Rehmannia Decoction). If the syndrome is slightly severe or treatment is delayed, use Taohao Chengqi Tang (Peach Kernel Decoction to Inherit the Command). Only when the condition is severe and treatment is significantly delayed should one use Didang Tang (Diding Decoction) or Didang Wan (Diding Pill). These are potent medicines and unsuitable for mild cases. Apply similar logic to other medications.