五十七难曰∶泄凡有几，皆有名不？
然∶泄凡有五，其名不同。有胃泄，有脾泄，有大肠泄，
有小肠泄。有大瘕泄，名曰后重。
泄，利也。其证有五，故有五泄之名。后重者，专指大瘕泄而言。盖肾邪下结，气坠不升故
也。此五泄之目，下文详之。
胃泄者，饮食不化，色黄。
胃泄者，甲木之克戊土也。胃主纳谷，风木之邪乘之，胃腑郁迫，水谷不化，必脉弦肠鸣。
黄者，胃土之色。经曰∶春伤于风，夏生飧泄者是也。
脾泄者，腹胀满泄注，食即呕吐逆。
脾泄者，脾土湿寒，不能蒸水化气，故水谷并下，胀满泄注也。食即呕吐者，脾弱下陷，则
胃逆也，必所下多水，脉缓，腹不痛。经曰∶湿甚则濡泄者是也。
大肠泄者，食已窘迫，大便色白，肠鸣切痛。
大肠泄者，肠虚气不能摄，故胃方实，即迫注于下，窘迫不及少待也。色白者，大肠属庚金，
白，金之色也。肠鸣切痛者，气不和则攻冲，故鸣而痛也。经曰∶清气在下，则生飧泄者是也。
小肠泄者，溲而便脓血，少腹痛。
小肠泄者，小肠属丙火，不化寒水。郁于湿土之中，内热淫蒸，脓血腐化。又小肠与心为表
里，心主血，盖气不相摄，而便脓血，小便亦不禁也。小肠之气郁冲，下达膀胱，膀胱近少腹，
故少腹痛也。此即血痢之类耳。
大瘕泄者，里急后重，数至圊而不能便，茎中痛，此五泄之要法也。
大瘕泄者，邪气结于下，成 瘕而不散也。里急后重者，肠气急迫；肛门重坠也。数至圊而
不能便者，皆 结不散，故欲便而不爽也。茎中痛者，乃湿郁为热，大便气不能达，则移于小
便也。此即古之滞下，今名痢疾者是也。
The Fifty-Seventh Difficulty states: How many types of diarrhea (Xie) are there, and do they all have names?
It is answered: There are five types of diarrhea, and their names differ. There is Stomach Diarrhea (Wei Xie), Spleen Diarrhea (Pi Xie), Large Intestine Diarrhea (Da Chang Xie), Small Intestine Diarrhea (Xiao Chang Xie), and Da Jia Diarrhea (Da Xia Xie). Da Jia Diarrhea is named "Hou Zhong" (Tenesmus/Heaviness in the rectum).
"Xie" refers to purging or loose stools. Since there are five types of syndromes, there are five names for diarrhea. The term "Hou Zhong" specifically refers to Da Jia Diarrhea. This is because pathogenic factors from the Kidney accumulate downward, causing Qi to sink and fail to ascend. The categories of these five diarrheas will be detailed in the following text.
Stomach Diarrhea is characterized by undigested food in the stool and yellowish color.
Stomach Diarrhea results from Wood (Jia Wood, representing Wind/Liver) overcoming Earth (Wu Earth, representing the Stomach). The Stomach governs the reception of grains; when Wind-Pathogen invades it, the Stomach Fu organ becomes stagnant and pressured, leading to the failure to digest water and grain. This inevitably presents with a wiry pulse and borborygmus. Yellow is the color of Stomach Earth. As stated in the Classics: "If injured by Wind in Spring, Sunxi diarrhea (diarrhea with undigested food) arises in Summer."
Spleen Diarrhea is characterized by abdominal distension and fullness, watery diarrhea, and vomiting/regurgitation immediately after eating.
Spleen Diarrhea occurs because Spleen Earth is damp and cold, failing to vaporize water to transform Qi. Consequently, water and grain descend together, causing distension, fullness, and watery diarrhea. Vomiting immediately after eating occurs because Spleen deficiency leads to sinking, causing Stomach Qi to rebel upward. The excrement will likely contain much water, the pulse will be moderate/slow, and the abdomen will not hurt. As stated in the Classics: "When Dampness is excessive, Ru diarrhea (damp diarrhea) occurs."
Large Intestine Diarrhea is characterized by urgency and distress immediately after eating, white-colored stool, borborygmus, and severe pain.
Large Intestine Diarrhea happens because the intestines are deficient, and Qi fails to secure and retain. Thus, when the Stomach is full, contents are forced downward urgently, leaving no time to wait. The stool is white because the Large Intestine belongs to Geng Metal, and white is the color of Metal. Borborygmus and severe pain occur because disharmony of Qi leads to attacking and rushing, causing both noise and pain. As stated in the Classics: "When Clear Qi remains below, Sunxi diarrhea arises."
Small Intestine Diarrhea is characterized by passing pus and blood in both urine and stool, and lower abdominal pain.
Small Intestine Diarrhea occurs because the Small Intestine belongs to Bing Fire and fails to transform Cold Water. Cold water stagnates within Damp Earth, internal Heat overflows and steams, causing pus and blood to rot and form. Furthermore, the Small Intestine and Heart are exterior-interior partners; the Heart governs Blood. Because Qi fails to control each other, pus and blood are passed in the stool and urine, and urination is also incontinent. The Qi of the Small Intestine stagnates and rushes downward to the Bladder. Since the Bladder is near the lower abdomen, lower abdominal pain occurs. This belongs to the category of bloody dysentery.
Da Jia Diarrhea is characterized by internal urgency, tenesmus (heaviness in the rectum), frequent trips to the toilet without successful defecation, and pain in the urethra. This is the essential principle among the five diarrheas.
Da Jia Diarrhea occurs because pathogenic factors knot at the lower part, forming a mass (Jia) that does not dissipate. "Internal urgency and tenesmus" refers to urgent intestinal Qi and heaviness/dragging sensation in the anus. Frequent trips to the toilet without successful defecation occur because the knotting does not dissipate, so one desires to defecate but cannot feel relieved. Pain in the urethra occurs because Dampness stagnates and transforms into Heat; when the Qi of the stool cannot reach, it shifts to the urine. This is what was anciently called "Zhi Xia" (stagnant downflow) and is now named Dysentery (Li Ji).