痢疾古名滞下，亦名肠 。以其滞涩肠脏，下多不快而 有声也。或赤或白，或赤白
相杂，或下肠垢而无糟粕，或糟粕相杂，虽有痛不痛之异，然皆里急后重，逼迫恼人。
痢疾古有赤热白冷，及五色分属五脏之辨，然脏腑寒热，当以脉症互参，虽有前说，存
之而已，若执此认病，泥矣。
《准绳》谓后重因邪压大肠坠下者，当用大黄、槟榔辈。如罗谦甫水煮木香膏、东垣白
术安
胃散等方。泻其所压之邪，则后重自除。若邪已泻，其重仍在者，知大肠虚滑，不能自收而
重，当用御米壳等涩剂，固其滑，收其气。用亦愈也。议论自正，但水煮木香、白术安胃二
方，皆以御米壳为君，且有乌梅、五味子、白芍、诃子，并无槟榔、大黄，而云然者，岂未
之察耶。
又谓大肠为邪坠下之重，其重至圊后不减，大肠虚滑不收之重，其重至圊后随减。愚谓
邪坠之重，圊后当减；虚滑之重，圊后不减。兹反言之，亦有误耶。
又谓休息痢多因兜住积滞，以致时作时止，宜四君子吞驻车丸，再投去积，却用兜剂。
按∶四君、驻车都非去积之剂，然议论自正。
败毒散，发散风湿，益元散解利热邪，故俱治发热下利。
治痢大法∶后重者宜下；腹痛者宜和；身重者除湿；脉弦者去风；脓血稠粘，以重药竭
之；身冷自汗，以毒药温之；风邪内缩者，汗之则愈； 溏为利者，温之而已。又曰∶在表者发
之，在里者下之，在上者涌之，在下者竭之，身表热者内疏之，小便涩者分利之，盛者和之
，去者送之，过者止之。
又曰∶食寒冷者，宜温热以消导之；伤湿热者，宜苦寒以内疏之；风邪内陷者升举之；
湿气
内盛者分利之；里急者下之；后重者调之；腹痛者和之；洞泄肠鸣无力，不及拈衣，脉细微
而弱者，温之收之；脓血稠粘，数至圊而不能便，脉洪大而有力者，下之寒之。
痢疾在古代被称为“滞下”，也被称为“肠澼”。这是因为病邪导致肠道脏腑气机阻滞涩滞，排便次数多但不畅快，且伴有肠鸣音。大便颜色或红或白，或红白相间，或排出肠道黏液垢腻而无食物残渣，或与食物残渣混杂。虽然有的有疼痛，有的没有疼痛，但都表现为里急后重（腹痛窘迫，时时欲便，肛门重坠，便出不爽），症状紧迫恼人。
古代对于痢疾有“赤色属热、白色属寒”以及“五色分别对应五脏”的辨析。然而，脏腑的寒热属性，应当通过脉象和症状相互参照来判断。虽然有上述说法，保留作为参考即可；如果拘泥于此来认定疾病，那就局限了。
《医学准绳六要》认为，后重是因为邪气压迫大肠导致下坠，应当使用大黄、槟榔这类药物。例如罗谦甫的水煮木香膏、李东垣的白术安胃散等方剂。泻去所压迫的邪气，后重自然消除。如果邪气已经泻去，但沉重感仍然存在，说明大肠虚滑，不能自行收敛而导致沉重，应当使用御米壳等收涩剂，固摄滑脱，收敛正气。这样使用也能痊愈。这种议论本身是正确的，但是水煮木香膏和白术安胃散这两个方子，都以御米壳为君药，并且含有乌梅、五味子、白芍、诃子，并没有槟榔和大黄，却说要用大黄、槟榔，这难道是没有仔细考察吗？
又认为：因邪气下坠导致的后重，排便后沉重感不减轻；因大肠虚滑不收导致的后重，排便后沉重感随即减轻。我认为：邪气下坠的后重，排便后应当减轻；虚滑的后重，排便后不减轻。这里说反了，也是有错误的吧。
又认为：休息痢多因为过早使用收涩药兜住积滞，导致病情时好时坏，适宜用四君子汤吞服驻车丸，然后再投用去积导滞的药物，最后再用收涩剂。按：四君子汤和驻车丸都不是去积导滞的方剂，但这种议论本身是正确的。
治疗痢疾的大法：后重的宜用攻下法；腹痛的宜用调和法；身体沉重的宜祛除湿邪；脉弦的宜祛风；脓血稠粘的，用重剂攻逐；身冷自汗的，用温性药物温补；风邪内陷的，发汗则愈；水样便为泄利的，温中即可。又说：病在表的，用发汗法；病在里的，用攻下法；病在上的，用涌吐法；病在下的，用竭除法；体表热的，用内疏法；小便涩滞的，用分利法；邪盛的，用调和法；正气去的，用送扶法；邪气过盛的，用止涩法。
又说：饮食生冷导致的，宜用温热药以消导之；损伤湿热导致的，宜用苦寒药以内疏之；风邪内陷的，宜升举之；湿气内盛的，宜分利之；里急的，宜攻下之；后重的，宜调气之；腹痛的，宜调和之；洞泄肠鸣无力，甚至来不及拈衣（形容极度虚弱），脉细微而弱的，宜温补收敛；脓血稠粘，频繁如厕却不能排便，脉洪大而有力的，宜攻下寒凉。
Dysentery was anciently known as "Zhi Xia" (Stagnant Downward Flow), also called "Chang Pi" (Intestinal Mucus Discharge). This is because the stagnation and涩滞 (astringency/stagnation) of the intestinal organs result in frequent but unsatisfactory defecation accompanied by borborygmus (bowel sounds). The stool may be red, white, or a mixture of both; it may consist of intestinal mucus without undigested food, or mixed with undigested food. Although there are differences regarding the presence or absence of pain, all cases present with tenesmus (urgent desire to defecate with heavy sensation in the anus and incomplete evacuation), which is distressing and aggravating.
Ancient texts distinguished dysentery based on the principle that red indicates heat and white indicates cold, and further categorized five colors corresponding to the five Zang organs. However, the cold-heat nature of the Zang and Fu organs should be determined by correlating pulse and symptoms. While these previous theories exist for reference, rigidly adhering to them to diagnose diseases is limiting.
The *Zhun Sheng* (Standard for Medical Practice) states that tenesmus caused by pathogenic factors pressing down on the large intestine should be treated with substances like Da Huang (Rhubarb Rhizome) and Bing Lang (Areca Seed). Examples include Luo Qianfu's Shui Zhu Mu Xiang Gao (Boiled Aromatic Wood Paste) and Li Dongyuan's Bai Zhu An Wei San (Atractylodes Macrocephala Stomach-Calming Powder). By purging the compressing pathogens, tenesmus will naturally resolve. If the pathogens have been purged but the heaviness remains, it indicates deficiency and slipping of the large intestine, unable to contract itself, causing heaviness. In such cases, astringents like Yu Mi Ke (Pericarpium Papaveris) should be used to secure the slipping and gather the Qi. Such treatment can also lead to recovery. Although this reasoning is sound, one must note that both Shui Zhu Mu Xiang Gao and Bai Zhu An Wei San use Yu Mi Ke as the sovereign drug and contain Wu Mei (Mume Fruit), Wu Wei Zi (Schisandra Berry), Bai Shao (White Peony Root), and He Zi (Chebula Fruit), but do not contain Bing Lang or Da Huang. To claim they require Da Huang and Bing Lang suggests a lack of careful examination.
It is further stated: Tenesmus due to pathogenic sinking does not decrease after defecation; tenesmus due to large intestine deficiency and slipping decreases immediately after defecation. I argue: Tenesmus from pathogenic sinking should decrease after defecation; tenesmus from deficiency and slipping should not decrease. The original text reverses this, which is an error.
It is also stated: Rest dysentery often results from prematurely using astringents to trap accumulated stagnation, leading to intermittent episodes. It is suitable to take Zhu Che Wan (Stop Dysentery Pill) swallowed with Si Jun Zi Tang (Four Gentlemen Decoction), then administer drugs to remove accumulation, and finally use astringents. Note: Neither Si Jun Zi Tang nor Zhu Che Wan are formulas for removing accumulation, although the reasoning is fundamentally correct.
Bai Du San (Detoxification Powder) disperses wind-dampness, and Yi Yuan San (Benefit Primordial Powder) clears and benefits against heat pathogens; therefore, both treat fever accompanied by diarrhea/dysentery.
General principles for treating dysentery: For tenesmus, use purgation; for abdominal pain, use harmonization; for heavy body, eliminate dampness; for wiry pulse, dispel wind; for thick and sticky pus and blood, use heavy agents to exhaust the pathogen; for cold body and spontaneous sweating, use toxic/warm agents to warm; for internal contraction of wind pathogens, induce sweating for cure; for watery stools indicating diarrhea, apply warming. Furthermore: For exterior conditions, use diaphoresis; for interior conditions, use purgation; for upper conditions, use emesis; for lower conditions, use exhaustion/clearance; for internal heat manifesting externally, use internal drainage; for astringent urination, use differentiation and promotion of urination; for excess conditions, use harmonization; for depleted conditions, use support; for excessive conditions, use astringency.
Furthermore: For injuries from cold and raw foods, use warm and hot agents to digest and guide out; for injuries from damp-heat, use bitter-cold agents to internally drain; for internal depression of wind pathogens, use lifting and raising; for internal abundance of dampness, use differentiation and promotion of urination; for urgency, use purgation; for tenesmus, regulate Qi; for abdominal pain, harmonize; for profuse diarrhea with bowel sounds, weakness, inability to lift clothes, and fine, thin, weak pulses, use warming and astringing; for thick and sticky pus and blood, frequent visits to the toilet with inability to pass stool, and surging, large, and forceful pulses, use purgation and cooling.