《经》曰∶协热而利者，其肠必垢；协寒而利者，其溏似 。寒者温之、涩之，热
则清之、通之。此古人之治法也。至夫痘疮养脓之时，有泄泻者，最为大忌，盖恐中气
虚而毒伏陷也。故专以温补止涩之法为正，然更有一种利清水者，利脓血者，又不可与
寒凉者同论而用止涩。假如曾有大渴饮水过多，蓄聚于中，溃灌肠胃，令乃作利清水
者，此名蓄水，泄水去尽则止也。更有因痘不收，以成倒靥，幸或中气充实，毒不得
留，乃大便而下脓血者为倒靥泄也。泄尽脓血，为毒出而自愈也。若不知此二端，妄投
止涩，则根蒂未除。枝蔓滋长，源泉欲塞，决溃更深矣。
夫痘疮出形起发，并不宜泄泻者，恐里气虚弱，毒邪不出，反成陷伏耳。然至成浆
之时，较之于前，殆有甚焉。盖前则其病未久，脾胃尚强，犹可任之，今则病久而津液
已衰，脾胃已弱。若复泄泻，则重竭于内，而方张之毒，不能成就于外，是以或为痒
塌，或为倒靥，或为寒战切牙，虚惫而死，治宜轻则参 桂果，重则木香异攻。然候至
灌脓，则元气尽耗于表，中气必虚，虚则下陷而肠鸣，失气便溏泄泻，所易至也。凡用
药调理者，切宜预为谨慎也。
夫痘疮初出腹痛者，是毒在里也。如起发不透而腹痛者，是有陷伏也。然在作脓，
则毒已出，又无陷伏，而忽然腹痛，其人不大便者，是必因有燥尿也，宜通导之。若便
清者，是必受冷也，宜温涩之。若其出已尽，其发已透，其脓已成是表无邪也。兼能
食，小便清，是里无邪也。而忽腹胀作痛，烦燥喘促，痘疮色变。如灰木之形状者，此
必由伤食而得之，宜先消之，次与之养脾焉可也。
《黄帝内经》说：伴随发热而腹泻的，大便中必然夹杂污浊垢腻之物；伴随寒象而腹泻的，大便稀薄如水。对于寒性腹泻，治疗应采用温中和固涩的方法；对于热性腹泻，则应采用清解和通下的方法。这是古代医家的治疗法则。到了痘疮化脓阶段，如果出现腹泻，是最为忌讳的，因为担心中气虚弱导致毒邪内陷伏留。因此，专门采用温补和止涩的方法作为正治之法。然而，还有一种情况是排出清水或脓血，这又不能与一般的寒凉证同论并简单使用止涩法。假如患者曾有大渴饮水过多，水液蓄积在体内，溃灌肠胃，从而导致排出清水，这种情况名为“蓄水”，待泄出的水液排尽后腹泻自然停止。更有因痘疮不能正常收靥（愈合），形成倒靥（痘疮内陷），幸好中气充实，毒邪无法滞留，于是通过大便排出脓血，这称为“倒靥泄”。当脓血排尽，说明毒邪已出，疾病便会自愈。如果不知道这两种情况，妄用止涩药物，那么病根未除，反而会导致病情枝蔓滋长，如同堵塞水源源头，最终导致决堤溃败更加严重。
痘疮发出形态、起发阶段，都不宜出现腹泻，因为担心里气虚弱，毒邪不能透发出来，反而造成内陷伏留。然而到了成浆阶段，比之前更为严重。因为此前病程不久，脾胃功能尚强，还可以承受；如今病程日久，津液已经衰少，脾胃功能已经虚弱。如果再发生腹泻，就会使内部元气双重耗竭，而正在旺盛发展的毒邪，不能在外部成就（化为脓浆），因此或者出现瘙痒塌陷，或者出现倒靥，或者出现寒战咬牙，因虚惫而死。治疗宜轻症用人参、桂枝、茯苓等药，重症用木香异攻散。然而等到灌脓阶段，元气已大量消耗于体表，中气必然虚弱，虚弱则气机下陷而出现肠鸣，失气且大便溏泄，这是容易发生的。凡是用药调理者，务必预先谨慎对待。
痘疮刚发出时出现腹痛，说明毒邪在里。如果起发不透畅而腹痛，说明有邪气内陷伏留。然而到了作脓阶段，毒邪已经透出，又没有内陷伏留，却忽然腹痛，且患者不大便的，一定是因为有燥屎阻滞，应当采用通导的方法。如果大便清稀的，一定是受了寒冷，应当采用温中和固涩的方法。如果痘疮已经出齐，起发已经透达，脓液已经形成，说明表无邪气。兼能进食，小便清利，说明里无邪气。此时如果忽然腹胀疼痛，烦躁气喘急促，痘疮颜色改变，呈现如灰木般的枯槁形状，这一定是由伤食引起的，应当先采用消食导滞的方法，其次再给予健脾养脾的药物即可。
The *Classic* states: Diarrhea accompanied by heat implies that the feces will be turbid and foul; diarrhea accompanied by cold implies that the stool will be watery and thin. For cold-type diarrhea, warming and astringing methods are used; for heat-type diarrhea, clearing and purging methods are used. This is the treatment principle of ancient physicians. During the stage of pustule formation in smallpox, if diarrhea occurs, it is strictly contraindicated, as there is fear that deficiency of Middle Qi (Spleen and Stomach energy) will cause the pathogenic toxin to sink inward and become latent. Therefore, the orthodox treatment is specifically to use warming, tonifying, and astringing methods. However, there is another type involving the discharge of clear water or pus and blood, which cannot be discussed together with cold-heat patterns nor treated simply with astringents. For instance, if a patient previously drank excessive amounts of water due to intense thirst, causing water accumulation in the middle jiao, flooding the intestines and stomach, leading to the discharge of clear water, this condition is named "Water Accumulation" (Shui Ji). The diarrhea will stop once the accumulated water is discharged. Furthermore, if the smallpox fails to heal properly, resulting in inverted lesions (Dao Ye), but fortunately the Middle Qi is sufficient so the toxin cannot remain, the pus and blood may be discharged via the stool. This is called "Inverted Lesion Diarrhea." Once the pus and blood are exhausted, indicating the toxin has exited, the disease will heal spontaneously. If one does not understand these two scenarios and recklessly administers astringents, the root cause remains, allowing the pathology to branch out and grow; blocking the source of the spring leads to deeper collapse and rupture.
During the eruption and rising stages of smallpox, diarrhea is generally inadvisable, fearing that interior Qi deficiency will prevent the toxin from being expelled outward, instead causing it to sink and become latent. However, during the stage of fluid filling (becoming pustules), the situation is even more critical than before. Previously, the illness was recent, and the Spleen and Stomach were still strong, capable of bearing the burden; now, after a prolonged illness, body fluids are depleted, and the Spleen and Stomach are weak. If diarrhea recurs, it doubly exhausts the interior, and the flourishing toxin cannot mature externally. Consequently, symptoms such as itching and collapsing, inverted lesions, chills with teeth grinding, and death from extreme debility may occur. Treatment should involve mild cases using *Renshen* (Ginseng Root), *Guizhi* (Cinnamon Twig), and *Fuling* (Poria); severe cases should use *Muxiang Yigong San* (Aucklandia Decoction for Overcoming Attack). However, upon reaching the pus-filling stage, Yuan Qi (Original Qi) is largely consumed at the exterior, and Middle Qi must be deficient. Deficiency leads to sinking Qi, manifesting as borborygmus (intestinal rumbling), flatus, and loose stools or diarrhea, which are common occurrences. Practitioners using medicinal regulation must exercise utmost caution in advance.
Abdominal pain occurring when smallpox first emerges indicates that the toxin is in the interior. Abdominal pain during incomplete eruption indicates internal sinking and latent pathogens. However, during the pus-forming stage, the toxin has already emerged, and there is no sinking or latency. If abdominal pain suddenly occurs and the patient has constipation, it is certainly due to dry fecal impaction, requiring purgative and guiding methods. If the stool is clear and watery, it is due to cold invasion, requiring warming and astringing methods. If the eruption is complete, the rising phase is thorough, and pus has formed, there is no pathogen on the exterior. Combined with the ability to eat and clear urination, there is no pathogen in the interior. If sudden abdominal distension and pain occur, accompanied by irritability, panting, and changes in the color of the smallpox lesions to a dull, wood-like gray, this is certainly caused by food stagnation. One should first employ digestion-promoting methods, followed by spleen-nourishing treatments.