《经》曰∶阳气在下，则生飧泄。盖积热之气，不能上升，即下注而为泄泻，故治
泻剂中多加升药者，恐其气下陷也。又曰∶湿胜则泻。总病初而泻者为热，病久而发者
为寒。水液澄澈，清冷而色白者，皆属于寒；青黄赤黑而燥涩者，皆属于热。泻利完
谷不化，身凉不渴，脉迟而微，小便清白不涩者，虚寒也，宜用参、术、炮姜、炙草之
类。小便赤涩，完谷消化，身热发渴，而脉洪数者，实热也，宜用木通、猪苓、赤茯之
类。在初出以及收靥之际，暂泻无妨，惟起脓灌脓而泻者，最须急治，但求其泻之因以
治之，不必治泻之为病也。若每日只一二次者，亦不可轻用止涩，以致毒瓦斯不得走泄，
则反留余毒，变生别症，惟宜调固中气，听其天然。百病强行止遏，皆非良法，犹之以
力制人，何如以德服人之为胜！
凡疮未出而利者，是邪气并于里，肠胃热甚，而传化失常也，宜从热毒而治。如疮
已出而利者，是邪气并于表，正气方逐邪气，故主乎表而不主里。里气适虚，不能运
纳水谷，故亦自利宜从气虚而治。如泻利而不渴者，是脏寒下利也，宜从温补而治。更
有方患痘疮，身有大热，因食冷物，或冷药过服，是以泄泻腹胀，其已出疮疹，乃瘢白
而无血色者，此由里寒而脾胃伏冷，是以荣卫不行，致令毒瓦斯内伏不出耳，宜急温脾透
托，则自血行气匀，而瘢白转红，泄泻俱愈矣。至于痘从后利下痂皮脓血者，是余毒
也，不宜收涩，惟宜解毒调中，以助营运，毒尽而利自止也。
《黄帝内经》说：阳气在下，就会发生完谷不化的泄泻。这是因为积热之气不能上升，反而向下注滞而形成泄泻，所以在治疗泄泻的方剂中多加用升提药的原因，是担心气机下陷的缘故。又说：湿气偏胜就会导致泄泻。总的来说，疾病初起时的泄泻属于热证，病程长久后发作的泄泻属于寒证。如果水液清澈、清冷且颜色发白，都属于寒证；如果颜色青黄赤黑且干燥涩滞，都属于热证。如果腹泻排出未消化的食物，身体凉爽且不口渴，脉象迟而微弱，小便清白且不涩滞，这是虚寒证，适宜使用人参、白术、炮姜、炙甘草之类的药物。如果小便红赤涩痛，虽然排出未消化食物但体内有热（注：此处原文“完谷消化”结合上下文“身热发渴”及实热证候，通常指热迫大肠或湿热下注，虽言完谷，实为热盛所致之利，或原文意指热邪导致传导失常，此处依原文直译并保留术语），身体发热且口渴，脉象洪大数急，这是实热证，适宜使用木通、猪苓、赤茯苓之类的药物。在痘疹初出以及收靥结痂的时候，暂时出现泄泻无妨，只有当脓疱溃破流脓时伴随泄泻的，才必须紧急治疗，只要探求引起泄泻的原因来治疗它，不必专门把泄泻当作疾病来治。如果每天只拉一两次，也不可轻易使用收敛止涩的药物，以免毒邪之气不得外泄，反而留下余毒，变化产生其他病症，只适宜调理巩固中焦脾胃之气，听任其自然恢复。各种疾病强行遏制止泻，都不是好方法，这就像是用强力制服人，哪里比得上用德行感化人的效果好呢！
凡是痘疮尚未发出而伴有腹泻的，是邪气并入于里，肠胃热势很盛，导致传化功能失常，应当从热毒方面治疗。如果痘疮已经发出而伴有腹泻的，是邪气并入于表，正气正在驱逐邪气，所以病机主要在于表而不在于里。此时里气恰好虚弱，不能运化纳受水谷，所以也会自然发生腹泻，应当从气虚方面治疗。如果腹泻但不口渴的，是脏腑寒冷导致的下利，应当从温补方面治疗。更有患痘疮的人，身体有大热，因为吃了生冷食物，或者过服寒凉药物，从而导致泄泻腹胀，那些已经发出的疮疹，却是瘢痕白色而没有血色的，这是由于里寒导致脾胃潜伏冷气，使得营卫之气运行不畅，致使毒邪之气内伏而不能透发出来，应当紧急温补脾胃并透托毒邪，这样自然气血运行均匀，白色的瘢痕转为红色，泄泻也就痊愈了。至于痘疮后期，大便下排痂皮、脓血的，这是余毒未尽，不宜使用收敛止涩之法，只适宜解毒调和中焦，以助气血营运，等毒邪排尽，腹泻自然停止。
The *Classic* (Huangdi Neijing) states: "When Yang Qi is located below, it generates sun-xie (diarrhea with undigested food)." This is because accumulated heat Qi cannot ascend and instead sinks downward to cause diarrhea. Therefore, in formulas for treating diarrhea, ascending herbs are often added to prevent the sinking of Qi. It also states: "Excess dampness leads to diarrhea." Generally, diarrhea occurring at the onset of a disease belongs to Heat, while diarrhea recurring after a long duration belongs to Cold. If the fluid is clear, cold, and white in color, it belongs to Cold; if it is green, yellow, red, or black and dry/astringent, it belongs to Heat. Diarrhea with undigested food, a cool body without thirst, a slow and faint pulse, and clear, non-astringent urine indicate Deficient-Cold; treatment should involve herbs such as Renshen (Ginseng), Baizhu (Atractylodes Macrocephala Rhizome), Paoyangjiang (Prepared Ginger), and Zhigancao (Honey-fried Licorice). Reddish, astringent urine, undigested food in stool accompanied by internal heat signs, a hot body with thirst, and a surging and rapid pulse indicate Excess-Heat; treatment should involve herbs such as Mutong (Akebia Stem), Zhuling (Polyporus), and Chifuling (Red Poria). During the initial eruption and the scabbing stage of smallpox/variolae, temporary diarrhea is not harmful. However, diarrhea accompanying the rupture and suppuration of pustules requires urgent treatment. One should treat the cause of the diarrhea rather than the diarrhea itself as a disease. If defecation occurs only once or twice daily, one should not lightly use astringents, lest the toxic factors fail to vent outward, retaining residual toxins and generating other complications. Instead, one should regulate and consolidate Middle Qi and allow nature to take its course. Forcibly suppressing any of the hundred diseases is not a good method; just as subduing people by force is inferior to winning them over by virtue, so too is forcibly stopping diarrhea inferior to resolving the underlying imbalance.
Diarrhea occurring before the eruption of sores indicates that pathogenic factors have merged into the interior, causing excessive heat in the intestines and stomach and disrupting transmission and transformation; treatment should address Heat-Toxin. Diarrhea occurring after the eruption of sores indicates that pathogenic factors have merged into the exterior, where Zheng Qi (Upright Qi) is expelling pathogens; thus, the pathology is primarily on the exterior rather than the interior. At this time, Interior Qi is slightly deficient and unable to transport and receive water and grain, leading to spontaneous diarrhea; treatment should address Qi Deficiency. Diarrhea without thirst indicates Cold in the Zang organs leading to lower purging; treatment should employ Warmtonic methods. Furthermore, in cases of smallpox/variolae where the patient has high fever but develops diarrhea and abdominal distension due to consuming cold foods or overdosing on cold medicines, and the erupted sores appear as pale, bloodless scars, this results from Interior Cold and latent cold in the Spleen and Stomach, which impedes the circulation of Ying and Wei Qi, causing toxic factors to remain internalized and unvented. Urgent warming of the Spleen and tonification to vent the toxin is required; this will harmonize Blood and Qi, turn the pale scars red, and cure the diarrhea. Finally, the passage of scabs, pus, and blood in the stool during the late stage of smallpox/variolae indicates residual toxins; astringents should not be used. Instead, detoxification and regulation of the Middle Jiao should be employed to assist Ying and Wei circulation; once the toxins are exhausted, the diarrhea will cease naturally.