温疫下后，脉证俱平，腹中有块，按之则疼，自觉有所阻而膨闷，或时有升降之
气，往来不利，常作蛙声，此邪气已尽，其宿结尚未除也，此不可攻。攻之徒损元气，气虚
益不能传送，终无补于治结，须饮食渐进，胃气稍复，津液流通，自能润下也。尝遇病愈后
食粥半月，结块方下，坚黑如石。
温疫愈后，脉证俱平，大便二三旬不行，时时作呕，饮食不进，虽少与汤水，呕
吐愈加，此为下格。然下既不通，必返于上。设误认翻胃，乃与牛黄、狗宝，及误作寒气，
而
以藿香、丁香、二陈之类，误也。宜调胃承气热服，顿下宿结及溏粪、粘胶恶物，臭不可当
者，呕吐立止。所谓欲求南风，须开北牖是也。呕止慎勿骤补，若少与参 ，则下焦复闭，
呕吐仍作也。此与病愈结存仿佛，彼则妙在往来蛙声一证，故不呕而能食。可见毫厘之差，
遂有千里之异。按二者大便俱闭，脉静身凉，一安一危者，在乎气通气塞之间而已矣。
温疫可下者，约三十余证，不必悉具，但见舌黄、心腹痞满，便于达原饮加大黄
下
之。设邪在膜原者，已有行动之机，欲离未离之际，得大黄促之而下，实为开门祛贼之法，
即使未愈，邪亦不能久羁。二三日后，余邪入胃，仍用小承气彻其余毒。大凡客邪贵乎早治
，乘人气血未乱，肌肉未消，津液未耗，病患不至危殆，投剂不至掣肘，愈后亦易平复。欲
为万全之策者，不过知邪之所在，早拔去病根为要耳。但要谅人之虚实，度邪之轻重，察病
之缓急，揣邪气离膜原之多寡，然后药不空投，投药无太过不及之弊。是以仲景自大柴胡以
下，立三承气，多与少与，自有轻重之殊。勿拘于下不厌迟之说，应下之证，见下无结粪，
以为下之早，或以为不应下之证，误投下药，殊不知承气本为逐邪而设，非专为结粪而设也
。必俟其粪结，血液为热所搏，变证迭起，是犹养虎遗患，医之咎也。况多有溏粪失下，
但
蒸作极臭如败酱，或如藕泥，临死不结者，但得秽恶一去，邪毒从此而消，脉证从此而退，
岂徒孜孜粪结而后行哉！假如经枯血燥之人，或老人血液衰少，多生燥结；或病后血气未复
，亦多燥结。在经所谓不更衣十日无所苦，有何妨害？是知燥结不致损人，邪毒之为殒命也
。要知因邪热致燥结，非燥结而致邪热也。但有病久失下，燥结为之壅闭，瘀邪郁热，益难
得泄，结粪一行，气通而邪热乃泄，此又前后之不同。总之，邪为本，热为标，结粪又其标
也。能早去其邪，安患燥结耶！
假令滞下，本无结粪，初起质实，频数窘急者，宜芍药汤加大黄下之。此岂亦因结粪而然
耶
积，若去积以为治，已成之积方去，未成之积复生，须用大黄逐去其邪，是乃断其生积之源
，营卫流通，其积不治而自愈矣。更有虚痢，又非此论。
或问∶脉证相同，其粪有结有不结者何也？曰∶原其人病至大盒饭即不行，续得蕴热，益难
得出，蒸而为结也。一者其人平素大便不实，虽胃家热甚，但蒸作极臭，状如粘胶，至死不
结。应下之证，设引经论初硬后必溏不可攻之句，诚为千古之弊。
大承气汤
大黄（五钱） 浓朴（一钱） 枳实（一钱） 芒硝（三钱）
水姜煎服，弱人减半，邪微者各复减半。
小承气汤
大黄（五钱） 浓朴（一钱） 枳实（一钱）
水姜煎服。
调胃承气汤
大黄（五钱） 芒硝（二钱五分） 甘草（一钱）
水姜煎服。
按∶三承气汤，功用仿佛。热邪传里，但上焦痞满者，宜小承气汤；中有坚结者，加芒硝软
坚
，惟存宿结而有瘀热者，调胃承气宜之。三承气功效俱在大黄，余皆治标之品也。不奈汤药
者，或呕或畏，当为细末，蜜丸汤下。
温疫经过攻下治疗后，脉象和症状都趋于平稳，但腹中有硬块，按压时疼痛，自觉有阻滞感且腹部胀闷，有时会有升降之气往来不畅，常发出类似蛙叫的声音。这是邪气已经清除，但体内宿积尚未排除的表现，此时不可再用攻下法。若强行攻下，只会徒然损伤元气，气虚后更加无法推动大便排出，最终对消除积结毫无帮助。应当让饮食逐渐恢复，待胃气稍复，津液流通，大便自然能润通而下。我曾遇到病愈后吃粥半个月，积块才排下来，坚硬漆黑如石头一般。
温疫病痊愈后，脉象和症状都平稳，但大便二三十天不通，时常呕吐，饮食不进，即使只给少量汤水，呕吐反而加剧，这称为“下格”（下部闭塞导致上逆）。既然下部不通，气机必然反逆于上。如果误认为是翻胃（一种以朝食暮吐或暮食朝吐为特征的病症），而给予牛黄、狗宝等药；或者误认为是寒气，而使用藿香、丁香、二陈汤之类温燥药物，都是错误的。适宜用调胃承气汤（调和胃气的承气汤）热服，一次顿服，使宿积及稀便、粘胶状恶臭物质排出，呕吐立刻停止。这就是所谓的“欲求南风，须开北牖”（想要吹进南方的风，必须打开北面的窗户，比喻通过开通下部来缓解上部症状）。呕吐停止后，切忌急于进补，如果稍许给予人参，会导致下焦再次闭塞，呕吐仍会发作。这种情况与前述“病愈后积结尚存”相似，不同的是前者妙在出现“往来蛙声”这一证候，所以不呕吐且能进食。可见毫厘之差，结果就有千里之异。按这两种情况大便都闭结，脉静身凉，一个平安一个危险，关键在于气机是通畅还是闭塞。
温疫病可以使用攻下法的，大约有三十多种证候，不必全部具备，只要见到舌苔发黄、心腹部痞塞胀满，就可以用达原饮（直达膜原的方剂）加大黄进行攻下。假如邪气在膜原（半表半里之位），已有变动之机，处于欲离未离之际，得到大黄催促而下，这确实是开门驱贼的方法，即使病未全愈，邪气也不能久留。两三天后，余邪入胃，仍用小承气汤（轻下热结的方剂）清除残余毒邪。大凡外感邪气贵在早治，趁着患者气血未乱、肌肉未消、津液未耗之时，病患不至于危殆，用药也不至于掣肘，病后也容易平复。想要万全的策略，不过是知道邪气所在，尽早拔除病根罢了。但要估量人的虚实，衡量邪气的轻重，察看病情的缓急，揣测邪气离开膜原的程度，然后下药才不会空投，避免太过或不及的弊病。因此张仲景从大柴胡汤以下，设立三承气汤，多与少与，自有轻重之别。不要拘泥于“攻下不宜过早”的说法，对于应当攻下的证候，见不到干结粪便，就认为攻下过早；或者对于不应攻下的证候，误投下药，殊不知承气汤本是为了驱逐邪气而设，并非专为干结粪便而设。一定要等到粪便结硬，血液被热邪搏结，变证迭起，这如同养虎遗患，是医生的过错。况且多有稀便因未及时攻下，被蒸灼得极臭如败酱，或如藕泥，临死都不结硬的，只要秽恶一去，邪毒从此消退，脉证从此退去，岂能孜孜以求粪便结硬后才行动呢！假如经脉枯槁、血液燥热的人，或者老人血液衰少，多生燥结；或者病后气血未恢复，也多生燥结。正如经典所说，十天不大便但没有不适，有什么妨害？由此可知燥结本身不致损害人，邪毒才是致命的。要知道是因邪热导致燥结，而非燥结导致邪热。只是有病久失于攻下，燥结壅闭，瘀邪郁热，更加难以宣泄，一旦结粪下行，气通而邪热乃泄，这又是前后的不同之处。总之，邪气是本，热是标，结粪又是其标。若能尽早去除邪气，还怕燥结吗！
假令痢疾（滞下），本来就没有干结粪便，初起体质壮实，频繁窘迫急迫者，宜用芍药汤（调和气血治疗痢疾的方剂）加大黄攻下。这难道也是因为有干结粪便吗？如果是积滞，若只去除已成之积，未成之积又会再生，必须用大黄驱逐邪气，这才是断绝产生积滞的源头，营卫流通，积滞不治自愈。更有虚寒痢疾，又不在此论中。
有人问：脉证相同，为什么有的粪便结硬，有的不结硬？回答说：原本其人患病至大便即不行，随后蕴生内热，更加难出，蒸灼而成结硬。另一种人平素大便不成形，虽然胃肠热甚，只是蒸灼得极臭，状如粘胶，至死都不结硬。对于应当攻下的证候，如果引用《伤寒论》中“初头硬后必溏不可攻”的句子，真是千古之弊病。
大承气汤（峻下热结的方剂）
大黄（五钱） 厚朴（一钱） 枳实（一钱） 芒硝（三钱）
用水、生姜煎服，体弱者减半，邪气轻微者各再减半。
小承气汤（轻下热结的方剂）
大黄（五钱） 厚朴（一钱） 枳实（一钱）
用水、生姜煎服。
调胃承气汤（缓下热结的方剂）
大黄（五钱） 芒硝（二钱五分） 甘草（一钱）
用水、生姜煎服。
按语：三承气汤功效相似。热邪传入里部，仅上焦痞满者，宜用小承气汤；中有坚结者，加芒硝软坚散结；只有宿积存在且有瘀热者，适合用调胃承气汤。三承气汤的功效主要在于大黄，其余都是治标的药物。不能耐受汤药者，若有呕吐或畏药，可将药研为细末，用蜜丸形式，汤送下。
After purgation for warm epidemic, the pulse and symptoms have both normalized. However, there are masses in the abdomen that cause pain upon pressure; the patient feels obstruction and abdominal distension/fullness. Occasionally, there is qi moving up and down without smooth flow, often producing sounds resembling frog croaking. This indicates that the pathogenic factor has been exhausted, but the accumulated residue remains. In this case, aggressive purgation must not be used. Purgation would merely deplete Yuan Qi (Original Qi); with Qi deficiency, peristalsis becomes even more difficult, ultimately failing to resolve the accumulation. Diet should be gradually resumed until Stomach Qi recovers slightly, fluids circulate, and stool naturally moistens and passes. I once encountered a case where, after recovery, the patient consumed congee for half a month before the mass was passed; it was hard, black, and stone-like.
Following recovery from warm epidemic, the pulse and symptoms are normal, but defecation does not occur for twenty to thirty days. There is frequent vomiting and inability to eat or drink. Even small amounts of liquid induce worse vomiting. This is termed "Lower Obstruction" (Xia Ge). Since the lower pathway is blocked, Qi inevitably rebels upward. If mistakenly diagnosed as "Reversal Vomiting" (Fan Wei) and treated with Niuhuang (Calculus Bovis) or Goubao (Dog Gallstone), or if mistaken for Cold Qi and treated with Huoxiang (Agastache Herba), Dingxiang (Caryophylli Flos), or Erchen Tang (Two-Aged Decoction), these are errors. The appropriate treatment is Hot Administration of Tiaowei Chengqi Tang (Stomach-Regulating Purging Decoction) taken in one dose. This will promptly expel old accumulations, loose stools, and sticky foul-smelling waste, immediately stopping the vomiting. This illustrates the principle: "To seek the south wind, one must open the north window." After vomiting stops, do not hastily tonify. Administering Renshen (Ginseng Radix et Rhizoma) even in small amounts may cause re-obstruction of the Lower Jiao (Lower Burner) and recurrence of vomiting. This resembles the previous condition of residual accumulation post-recovery, but differs in that the presence of "frog-like sounds" allows the patient to eat without vomiting. Thus, a slight difference leads to vastly different outcomes. In both cases, defecation is blocked, the pulse is calm, and the body is cool; the difference between safety and danger lies solely in whether Qi is unobstructed or obstructed.
There are approximately thirty-plus indications for purgation in warm epidemics; all need not be present. If yellow tongue coating and epigastric/abdominal fullness/stuffiness are observed, Dahuang (Rhei Radix et Rhizoma) can be added to Dayuan Yin (Origin-Reaching Decoction) to purge. If the pathogen is at the Membrane Source (Mo Yuan - a location between exterior and interior) and shows signs of movement, on the verge of leaving but not yet gone, Dahuang promotes its downward expulsion. This is indeed a method of "opening the door to drive out the thief." Even if not fully cured, the pathogen cannot linger. Two or three days later, if residual pathogens enter the Stomach, Xiao Chengqi Tang (Minor Purging Decoction) should still be used to clear remaining toxins. Generally, external pathogens require early treatment while Qi and Blood are undisturbed, muscles are not wasted, and fluids are not depleted, preventing critical danger and facilitating easier recovery. The strategy for perfection is simply knowing the location of the pathogen and removing the root cause early. One must assess the patient's Deficiency/Excess, weigh the severity of the pathogen, observe the speed of the disease, and estimate how much the pathogen has moved from the Membrane Source. Only then can medicine be administered accurately, avoiding excess or insufficiency. Therefore, Zhang Zhongjing established the Three Chengqi Decoctions starting from Da Chaihu Tang (Major Bupleurum Decoction), varying dosages according to severity. Do not adhere rigidly to the saying that "purgation should not be delayed." For indications requiring purgation, if no dry feces are seen, one might wrongly consider purgation premature; or for non-indications, purgatives might be wrongly given. It is unknown that Chengqi Decoctions are designed to expel pathogens, not specifically for dry feces. Waiting until feces become hard and blood is bound by heat, leading to successive complications, is like nurturing a tiger and leaving trouble behind—a doctor's fault. Moreover, many cases involve loose stools that, due to failure to purge early, are steamed into extremely foul-smelling substances like spoiled sauce or lotus root mud, never hardening even until death. Once this filth is removed, the toxic pathogen dissipates, and pulse/symptoms recede. Why insist on waiting for hard feces? For individuals with dry blood and empty meridians, or the elderly with deficient blood, dry constipation often occurs; similarly, post-illness Qi/Blood deficiency often leads to dryness. As stated in classics, ten days without bowel movement without discomfort causes no harm. Thus, dryness itself does not harm; the toxic pathogen is fatal. Know that pathogenic heat causes dryness, not vice versa. However, in prolonged illness with failed purgation, dryness blocks Qi, trapping stagnant pathogens and heat, making release difficult. Once hard feces pass, Qi flows, and pathogenic heat is released—this is the difference between early and late stages. Ultimately, the pathogen is the root, heat is the branch, and dry feces are the branch of the branch. If the pathogen is removed early, why worry about dryness?
In the case of Dysentery (Zhixia), there is typically no dry feces. If the constitution is solid initially, with frequent, urgent, and difficult defecation, Shaoyao Tang (Peony Decoction) with added Dahuang should be used for purgation. Is this also due to dry feces? Regarding Accumulation (Ji), if only existing accumulation is treated, new accumulation will form. Dahuang must be used to expel the pathogen, cutting off the source of accumulation. With free Ying and Wei (Nutritive and Defensive Qi), accumulation heals spontaneously. Note that Deficient Dysentery falls outside this discussion.
Question: If pulse and symptoms are identical, why is feces sometimes hard and sometimes soft? Answer: In some cases, upon severe illness, bowel movement ceases immediately, followed by internal heat generation, which steams the contents into hardness. In others, who normally have loose stools, even with intense Stomach/Intestine heat, the stool becomes extremely foul and sticky but never hardens until death. Applying the classic rule "initially hard then loose means do not purge" to cases requiring purgation is a千古 (eternal) error.
Da Chengqi Tang (Major Purging Decoction):
Dahuang (Rhei Radix et Rhizoma) (5 qian), Houpo (Magnoliae Officinalis Cortex) (1 qian), Zhishi (Aurantii Fructus Immaturus) (1 qian), Mangxiao (Natrii Sulfas) (3 qian).
Decoct in water with Shengjiang (Zingiberis Rhizoma Recens). Reduce dosage by half for weak patients; halve again for mild pathogens.
Xiao Chengqi Tang (Minor Purging Decoction):
Dahuang (Rhei Radix et Rhizoma) (5 qian), Houpo (Magnoliae Officinalis Cortex) (1 qian), Zhishi (Aurantii Fructus Immaturus) (1 qian).
Decoct in water with Shengjiang (Zingiberis Rhizoma Recens).
Tiaowei Chengqi Tang (Stomach-Regulating Purging Decoction):
Dahuang (Rhei Radix et Rhizoma) (5 qian), Mangxiao (Natrii Sulfas) (2.5 qian), Gancao (Glycyrrhizae Radix et Rhizoma) (1 qian).
Decoct in water with Shengjiang (Zingiberis Rhizoma Recens).
Note: The functions of the three Chengqi Decoctions are similar. For Heat entering the interior causing only upper Jiao fullness, use Xiao Chengqi Tang. For firm accumulation in the middle, add Mangxiao to soften hardness. For old accumulation with stasis-heat, Tiaowei Chengqi Tang is suitable. The efficacy of all three relies primarily on Dahuang; others treat branches. For those unable to tolerate decoctions due to vomiting or aversion, grind into powder, form honey pills, and take with water.