中气不足，溲便为之变。(《素问》)
大便先硬后溏者，不可攻。(张仲景)
凡小溲赤涩为热，经曰∶肝有热则小便先赤也。(惕厉子)
凡小儿小便由睡中自遗者，谓之尿床，皆肾与膀胱有虚寒也。(《兰台规范》)
小儿初溲黄赤色，落地良久，凝如白膏者，谓之尿白。为伤脾所致，久而成疳。(夏禹
铸)
伤寒小水利者，太阳之气未剧，吉兆也。(张景岳)
凡病者，尿自遗而不如，为无治。(《集成》)
溲白为寒，混白如米泔者，为湿热。(周于蕃)
溲红为热，黄亦为热，若浅红淡黄者为阴虚，溺多心烦者不治。(周于蕃)
肠热者溺黄，肠寒者溺白。(周于蕃)
溲短黄涩痛，心热也；清长而利，心虚也。(周于蕃)
凡大便色青者为寒，然亦有因风泻者，其色亦青，肝木乘脾也。(《铁镜》)
水液澄清，下利清谷者为寒。(《铁镜》)
大便老黄色者，心、肺、脾三经实热；若淡黄色者，为虚热。(《铁镜》)
粪如蟹渤，暑湿内搏，脾热之证也。(江梦花)
大便酱色者属湿，白色者属脾虚。(夏禹铸)
大便味馊臭者伤食滞，一痛则便，便则痛减，味极秽臭，便时肛门恶热者，为极热。
(夏禹铸)
大便味如败卵腥臭者，伤乳食。(《集成》)
大便如红水而粘者，为暑热。(《集成》)
大便时急迫作声者属热。(《指南》)
大便黑如胶漆者，主湿热凝滞。(周于蕃)
大便热结，腹中坚满者，属有余；若新近得解，而不甚干结，或旬日不解，而全无胀意
，非阳明实邪。(张景岳)
按∶病寒即见寒证，病热即见热证，寒者温之，热者清之，此其易能也。若内真寒而外
假热
，内真热而外假寒，其中误人者甚伙。经云∶重寒则热，重热则寒。又曰∶寒甚则热，热甚
则寒。又曰重阴必阳，重阳必阴。又曰∶水极而火，火极而水。又曰∶阳盛格阴，阴盛格阳
。古人再三垂诫，反复立言，深恐证涉疑似，后世为其所惑耳。溲由前阴出，便由后阴出，
寒自寒，热自热，以此区辨，则真假能立判矣。(惕厉子)
Insufficiency of the Middle Qi (Middle Jiao energy) leads to abnormalities in urination and defecation. (*Suwen*)
When stool is initially hard and subsequently loose, purgative methods should not be used. (Zhang Zhongjing)
Generally, red and astringent urine indicates Heat syndrome. The Classics state: "If the Liver has Heat, the urine will first become red." (Ti Li Zi)
When children wet the bed by passing urine involuntarily during sleep, it is called enuresis. This is caused by deficiency-cold in the Kidney and Bladder. (*Lantai Guifan*)
When a child's initial urine is yellow-red and coagulates into a white paste-like substance after remaining on the ground for a long time, it is called "white urine." This is caused by Spleen injury and may develop into infantile malnutrition (Gan syndrome) over time. (Xia Yuzhu)
In Taiyang disease (Exterior syndrome), if urination is smooth, it indicates that the Taiyang Qi is not severely compromised, which is an auspicious sign. (Zhang Jingyue)
For any patient, involuntary loss of urine with inability to control it indicates a condition beyond treatment. (*Jicheng*)
White urine indicates Cold; turbid urine resembling rice wash water indicates Damp-Heat. (Zhou Yufan)
Red urine indicates Heat; yellow urine also indicates Heat. If the color is light red or pale yellow, it indicates Yin Deficiency. If there is polyuria accompanied by vexation, it is considered incurable. (Zhou Yufan)
Intestinal Heat results in yellow urine; Intestinal Cold results in white urine. (Zhou Yufan)
Short, yellow, astringent, and painful urination indicates Heart Heat; clear, long, and free urination indicates Heart Deficiency. (Zhou Yufan)
Generally, green-colored stool indicates Cold. However, diarrhea caused by Wind may also present with green color, which is due to Liver Wood overacting on the Spleen. (*Tiejing*)
Clear fluids with diarrhea containing undigested food indicate Cold. (*Tiejing*)
Old yellow stool indicates Excess-Heat in the Heart, Lung, and Spleen meridians; pale yellow stool indicates Deficiency-Heat. (*Tiejing*)
Stool resembling *xiebo* (a type of aquatic crustacean) indicates internal constraint of Summerheat-Dampness, a syndrome of Spleen Heat. (Jiang Menghua)
Sauce-colored stool belongs to Dampness; white stool belongs to Spleen Deficiency. (Xia Yuzhu)
Stool with a sour, foul odor indicates Food Stagnation. Pain precedes defecation, and pain alleviates after defecation. An extremely foul odor and a sensation of heat in the anus during defecation indicate Extreme Heat. (Xia Yuzhu)
Stool smelling like rotten eggs and fishy indicates injury from milk and food. (*Jicheng*)
Stool resembling red water and being sticky indicates Summerheat-Heat. (*Jicheng*)
Urgent defecation accompanied by sound indicates Heat. (*Zhinan*)
Black stool resembling glue or lacquer indicates stagnation of Damp-Heat. (Zhou Yufan)
Heat accumulation causing hard and full abdomen indicates an Excess syndrome (Yang excess). If stool was recently passed and is not very dry, or if no stool has been passed for ten days but there is absolutely no feeling of distension, it is not Yangming Excess pathogen. (Zhang Jingyue)
Commentary: When a disease is Cold, Cold signs appear; when a disease is Heat, Heat signs appear. Cold is treated with warming, and Heat is treated with clearing; this is straightforward. However, in cases of True Cold with False Heat, or True Heat with False Cold, misdiagnosis is very common. The Classics state: "Extreme Cold generates Heat, Extreme Heat generates Cold." It also says: "Severe Cold manifests as Heat, Severe Heat manifests as Cold." Furthermore: "Heavy Yin transforms into Yang, Heavy Yang transforms into Yin." And: "Water extreme becomes Fire, Fire extreme becomes Water." Also: "Excess Yang repels Yin, Excess Yin repels Yang." The ancients warned repeatedly and elaborated extensively, fearing that syndromes might be deceptive and confusing, leading later generations astray. Urine exits from the anterior yin opening, and stool exits from the posterior yin opening. Cold remains Cold, and Heat remains Heat. By distinguishing based on these characteristics, true and false can be immediately determined. (Ti Li Zi)