时疫便血，热邪深入也，先当辨其血色。鲜红者，清热为主，黄芩汤、三黄石膏汤、犀角地黄汤；血色
紫黯成块下者，逐瘀为主，桃仁承气汤、抵当汤，须按腹、胁有痛处，用之为确。时疫便血，散晦夹涎水者，
脾胃虚而脏腑伤也，归脾、补中、八珍可借用，并加乌梅。
时疫便血之后，多亡阴证，神昏耳聋，舌无苔而燥，
身痛不可转侧之类皆是，生脉、六味加阿胶，峻补其阴，然多不救也。
时疫便脓血与便血有燥湿之分。便血属燥热，凉润为主；便脓血属湿热，清热兼分利为主。
时疫初起，头痛发热便脓血者，即古所谓疫痢是也。不必治脓血，但解其表，表解则便数自减，决不可早施清
里攻下之药，即分利、清凉亦所当慎。盖邪方在表，清里邪则内陷深入，后极难治。且时疫一见便脓血，则烦渴之
热势反缓，盖热随利减也。所以苦寒之品不可浪用，惟以仓廪汤为主，详见夹痢条下。时疫传变至半表半里便脓血
者，柴葛解肌汤加苓、泽、木通、黄芩。时疫传变入里，烦、渴、谵妄悉具而便脓血者，黄芩汤、葛根芩连汤选
用。兼里急后重，腹中拒按者，加槟榔、大黄。时疫屡经
攻下而便脓血滑利者，当以养中、调气、养血为主，清热为佐。老人、虚人亦仿此例。
时疫属湿热，大便闭者少，间有闭者，乃平素胃阳强盛，多燥气也。夫本来阳盛，复受时疫，则湿热皆变为燥
热，虽兼表证未得汗，可下。以时疫与伤寒不同，伤寒邪从表入，有表证未得汗，必不可攻里；时疫邪从内发，虽
有表证，每每发表而不得汗，必待里气通而后表始得汗。所以时疫大便一闭，即有表证，亦当下之，不可逡巡也。
若初起未经表散，则当用三消饮下之为当。有表证尚可
下，则烦渴、谵妄，舌苔黄黑、燥烈、卷短，胸、腹硬痛诸证备见，更当分别轻重下之无疑。
又有大便闭而屡下不通者，则必有夹邪，当审之。有夹水者，水在肠中，则不下而自利；水在胃脘以上、则脉
多弦、多缓，往往上呕而不下利，且舌白而心下按之作响，虽用承气不能下行，故下之不通，当先用半夏、茯苓、
苍术消其水，而后下之，亦有可用大陷胸汤者，必胸上痛而手不可近，方为药与邪敌。有夹气者，气滞于胸膈之
间，主上逆而不下降，胸腹串痛而脉沉，当先以苏子、莱菔子、木香、槟榔顺其气而后下之。
有气虚而屡下不通者，属老人、虚人，其脉必兼无力，其色必悴，其肌肉必缓，其神必散。若下证全具，当
与大承气加人参，一服而宿垢顿下，或陶氏黄龙汤，或麻仁丸，参汤下，酌其里证之多寡用之。有血虚而屡下不通
者，属妇人产后，痈疽溃后，或平素阴虚及亡血，其脉必
兼涩，四物、六味、生脉及吴氏诸养荣方、麻仁丸选用，仍须蜜煎猪胆汁导之。
大凡时疫，大便一闭，即当下之。然须询其有无所苦，若无所苦，下尚可缓，有所苦而下之不通，又须察有
无夹邪及虚也。当下者十之五，可缓者十之三，夹邪者十之一耳。时疫如此，他病则不然。古语云∶伤寒下不厌
迟，时疫下不厌早，诚哉！斯言也。
时疫引起的便血，是热邪深入体内的表现，首先应当辨别血液的颜色。血色鲜红的，以清热为主要治法，可选用黄芩汤、三黄石膏汤、犀角地黄汤；血色紫暗并结成块状排出的，以逐瘀为主要治法，选用桃仁承气汤、抵当汤，必须结合按压腹部、胁肋部有疼痛感的症状，使用这些方剂才确切。时疫便血中，夹杂晦暗色泽和涎水的，是脾胃虚弱且脏腑受损的表现，可以借用归脾汤、补中益气汤、八珍汤，并加入乌梅。
时疫便血之后，多出现亡阴证，表现为神志昏迷、耳聋、舌面无苔且干燥、身体疼痛无法翻身转动等，可用生脉散、六味地黄丸加阿胶，峻猛地滋补其阴液，但大多难以救治。
时疫便脓血与便血在燥湿性质上有区别。便血属于燥热，以凉润为主；便脓血属于湿热，以清热兼分利（利尿祛湿）为主。时疫初起，出现头痛、发热、便脓血的，就是古人所说的疫痢。不必专门治疗脓血，只需解除表证，表证解除后，排便次数自然减少，决不可过早施用清里攻下的药物，即使是分利、清凉的药物也应当谨慎。因为邪气尚在体表，若清里则会导致邪气内陷深入，后期极难治疗。而且时疫一旦出现便脓血，烦渴的热势反而会减缓，这是因为热随排泄而减轻。所以苦寒之品不可滥用，主要以仓廪汤为主，详见夹痢条下。时疫传变至半表半里出现便脓血的，用柴葛解肌汤加茯苓、泽泻、木通、黄芩。时疫传变入里，烦渴、谵妄等症状具备且便脓血的，选用黄芩汤、葛根芩连汤。兼有里急后重、腹部拒按的，加槟榔、大黄。时疫经过多次攻下后，便脓血滑泄不止的，应当以养中、调气、养血为主，清热为辅。老人、体虚者也参照此例。
时疫属于湿热性质的，大便闭结的情况较少，偶尔有闭结的，是因为平时胃阳强盛，多有燥气。本来阳气旺盛，又感受时疫，则湿热都变为燥热，虽然兼有表证但未得汗，也可以攻下。因为时疫与伤寒不同，伤寒邪气从表入里，有表证未得汗，绝不可攻里；时疫邪气从内发出，虽然有表证，常常发表却不得汗，必须等待里气通畅后表证才能得汗。所以时疫一旦大便闭结，即使有表证，也应当攻下，不可犹豫。如果初起未经过表散，则应当用三消饮攻下为适宜。如果有表证尚可攻下，那么烦渴、谵妄、舌苔黄黑、干燥短缩、胸腹硬痛等各种症状都具备，更应当分别轻重进行攻下，毫无疑问。
又有大便闭结且多次攻下不通的，则必定有夹邪，应当仔细审察。有夹水邪的，水在肠中，则不下而自利；水在胃脘以上，则脉象多弦、多缓，往往上呕而下不利的，且舌白而心下按压作响，虽然用承气汤也不能下行，所以下之不通，应当先用半夏、茯苓、苍术消除水邪，然后再攻下，也有可用大陷胸汤的，必须胸上部疼痛且手不可触碰，才是药力与邪气相敌对。有夹气邪的，气滞于胸膈之间，主要向上逆而不下降，胸腹串痛且脉沉，应当先用苏子、莱菔子、木香、槟榔顺其气机然后再攻下。
有气虚导致多次攻下不通的，属于老人、体虚之人，其脉象必兼无力，面色必憔悴，肌肉必松弛，精神必涣散。如果下证完全具备，应当给予大承气汤加人参，一服后宿垢顿时排出，或者陶氏黄龙汤，或者麻仁丸，用人参汤送服，酌情根据里证的多少来使用。有血虚导致多次攻下不通的，属于妇人产后，痈疽溃破后，或平时阴虚及失血者，其脉象必兼涩，选用四物汤、六味地黄丸、生脉散及吴氏诸养荣方、麻仁丸，仍须用蜜煎猪胆汁导引通便。
大凡时疫，大便一旦闭结，就应当攻下。然而必须询问患者有什么痛苦，如果没有什么痛苦，攻下还可以暂缓，如果有痛苦而攻下不通，又必须检查有无夹邪及虚证。应当攻下的占十分之五，可以暂缓的占十分之三，夹邪的占十分之一罢了。时疫如此，其他疾病则不然。古语说：伤寒攻下不厌迟，时疫攻下不厌早，这话确实正确啊！
Hematochezia caused by epidemic febrile diseases indicates that heat pathogens have penetrated deeply into the interior. Initially, one must distinguish the color of the blood. If the blood is bright red, the primary treatment is to clear heat, using formulas such as Huangqin Tang (Scutellaria Decoction), Sanhuang Shigao Tang (Three Yellows and Gypsum Decoction), or Xijiao Dihuang Tang (Rhinoceros Horn and Rehmannia Decoction). If the blood is purplish-dark and forms clots upon discharge, the primary treatment is to expel blood stasis, using formulas such as Tao Ren Chengqi Tang (Peach Kernel and Rhubarb Decoction) or Didang Tang (Wait-and-See Decoction); these should only be used definitively when tenderness is present upon palpation of the abdomen and hypochondrium. In hematochezia from epidemic febrile diseases, if the stool contains darkish blood mixed with salivous fluid, it indicates deficiency of the Spleen and Stomach and injury to the Zang-Fu organs; formulas such as Guipi Tang (Restore the Spleen Decoction), Buzhong Yiqi Tang (Tonify the Middle and Augment Qi Decoction), or Bazhen Tang (Eight Treasure Decoction) may be borrowed, with Wumei (Mume Fruit) added.
Following hematochezia in epidemic febrile diseases, Yin exhaustion syndromes often occur, manifesting as coma, deafness, a tongue without coating and dry, body pain preventing turning over, etc. These can be treated with Shengmai San (Generate the Pulse Powder) or Liuwei Dihuang Wan (Six-Ingredient Rehmannia Pill) plus Ejiao (Donkey-Hide Gelatin) to vigorously tonify Yin, though prognosis is often poor.
There is a distinction between dryness and dampness in hematochezia versus dysentery-like pus and blood in stools during epidemics. Hematochezia belongs to dry-heat and is primarily treated with cooling and moistening methods; dysentery-like pus and blood belong to damp-heat and are primarily treated with clearing heat and promoting diuresis to separate dampness. At the onset of an epidemic, if headache, fever, and dysentery-like pus and blood appear, this corresponds to what ancients called "epidemic dysentery." There is no need to specifically treat the pus and blood; simply resolve the exterior syndrome. Once the exterior is resolved, the frequency of defecation will naturally decrease. One must absolutely avoid administering interior-clearing and purgative drugs early on, and even diuretic or cooling agents should be used with caution. This is because the pathogen is still at the exterior; clearing the interior would cause the pathogen to sink deeper inward, making subsequent treatment extremely difficult. Moreover, once dysentery-like pus and blood appear in epidemics, the intense heat of irritability and thirst often subsides, as heat diminishes with evacuation. Therefore, bitter-cold substances should not be used indiscriminately; Canglin Tang (Granary Lin Decoction) should be the primary formula (see details under the section on complicated dysentery). If the epidemic transmits to the half-exterior half-interior stage presenting with dysentery-like pus and blood, Chai Ge Jie Ji Tang (Bupleurum and Kudzu Release Muscle Decoction) with Fuling (Poria), Zexie (Alisma), Mutong (Akebia Stem), and Huangqin (Scutellaria Root) should be used. If the epidemic transmits into the interior, accompanied by irritability, thirst, delirium, and dysentery-like pus and blood, choose between Huangqin Tang (Scutellaria Decoction) or Gegen Qinlian Tang (Kudzu and Scutellaria-Coptis Decoction). If accompanied by tenesmus and abdominal resistance to pressure, add Binglang (Areca Seed) and Dahuang (Rhubarb Root). If dysentery-like pus and blood persist and become slippery despite multiple purgations, the primary treatment should be nourishing the middle, regulating Qi, and nourishing blood, with clearing heat as an adjunct. The elderly and the debilitated should follow this pattern.
Epidemics characterized by damp-heat rarely present with constipation. When constipation does occur, it is usually due to strong Stomach Yang and inherent dryness. Since the constitution is already Yang-excess, contracting an epidemic transforms damp-heat into dry-heat. Even if exterior symptoms exist without sweating, purgation may be indicated. This differs from Cold Damage (Shanghan): in Cold Damage, pathogens enter from the exterior, and if exterior symptoms persist without sweating, interior purgation is strictly contraindicated; in epidemics, pathogens originate from within. Although exterior symptoms may exist, releasing the exterior often fails to produce sweat; one must wait for the interior to unblock before the exterior can release via sweat. Therefore, once constipation occurs in epidemics, even with exterior symptoms, purgation is required without hesitation. If the exterior has not been released initially, Sanxiao Yin (Three Eliminations Decoction) should be used for purgation. If exterior symptoms allow for purgation, and symptoms such as irritability, thirst, delirium, yellow-black dry and short tongue coating, and hardness/pain in the chest and abdomen are all present, purgation should definitely be administered according to severity.
In cases of constipation where repeated purgations fail to relieve blockage, there is likely a complicating pathogen that must be examined. If water retention is involved: if water is in the intestines, diarrhea may occur spontaneously without constipation; if water is above the epigastrium, the pulse is often wiry or slow, often presenting with vomiting but no diarrhea, white tongue coating, and a resonant sound upon pressing below the heart; although Chengqi Decoctions cannot descend, purgation fails. In such cases, use Banxia (Pinellia Tuber), Fuling (Poria), and Cangzhu (Atractylodes Rhizome) to eliminate water first, then purge. Dadixiong Tang (Great Chest-Sinking Decoction) may also be used if there is severe pain in the upper chest that cannot be touched, indicating the medicine is confronting the pathogen. If Qi stagnation is involved: Qi stagnates in the chest and diaphragm, rising upward rather than descending, causing wandering pain in the chest and abdomen with a deep pulse. Use Suzi (Perilla Seed), Laifuzi (Radish Seed), Muxiang (Costus Root), and Binglang (Areca Seed) to regulate Qi first, then purge.
If purgation fails due to Qi deficiency, typically seen in the elderly or debilitated, the pulse will be weak, complexion sallow, muscles flaccid, and spirit scattered. If full purgative indications are present, give Dachengqi Tang (Major Order the Qi Decoction) plus Renshen (Ginseng Root); after one dose, accumulated feces should evacuate immediately. Alternatively, Taoshi Huanglong Tang (Dr. Tao's Yellow Dragon Decoction) or Mahuan Wan (Hemp Seed Pill) taken with Renshen decoction can be used, adjusted based on the extent of interior excess. If purgation fails due to Blood deficiency, typically seen postpartum in women, after ulceration of carbuncles/sores, or in those with chronic Yin deficiency or blood loss, the pulse will be choppy. Choose Siwu Tang (Four Substance Decoction), Liuwei Dihuang Wan (Six-Ingredient Rehmannia Pill), Shengmai San (Generate the Pulse Powder), Wu’s various Yingnong (Nourish the Nutritive) formulas, or Mahuan Wan (Hemp Seed Pill), and still employ honey-prepared pig bile suppositories for guidance.
Generally, in epidemics, once constipation occurs, purgation is indicated. However, one must inquire about the patient's distress. If there is little distress, purgation can be delayed; if there is distress and purgation fails, one must check for complicating pathogens or deficiency. About 50% require immediate purgation, 30% can be delayed, and 10% involve complicating pathogens. This applies to epidemics, not other diseases. As the ancient saying goes: "For Cold Damage, purgation is never too late; for epidemics, purgation is never too early." This statement is indeed true!