不大便，谓大便不通。盖因热蓄于胃，胃土燥裂，津液溃耗，以致大便不通。若见发渴谵语，潮热自汗，
脉实胀满等证，宜三承气汤选用。若以下后或发汗后，而大便乃不通者，此津液内竭，宜用蜜导或
□胆导法。若带呕者，未全入府人，虽有阳明症，不可攻之。若小便清者，知邪不在里，而仍在表，亦不可
攻心。若瘥后食早，胃气不能运行而不便，分轻重以消导之。若病后血少，肠胃燥涩而不便者，又分
老壮以滋润之。
太阳症下焦有热，小腹必满，应小便不利，今反利者，血症谛也。抵当汤主之。阳明症自汗出，腹发汗
应小便少，今反利者，津液内竭也，尿虽硬、不可攻之，宜蜜导法。少阴症而小便利者，虚寒症也，四逆
汤主之。
膀胱乃津液之府，气化则能出焉。若热畜于下，湿蕴于中，气因热伤，结而不散，甚则小腹硬满而痛，
小便闭而不通也。若饮水过多，或中湿发黄，皆以利小便为先。如汗后亡津液，阳明汗多，则以利小
便为戒。
经曰、阴虚则小便难。阴虚者，阳必凑之。盖因膀胱受热，，故小便□而不能流利。
小便数者，肾与膀胱俱虚，而有客热乘之也。二经既虚，致受客热，虚则不能制水，故令数，小便数则
水行□，□则小便不快，故令数。
四逆者，四肢逆而不温也。厥者，手足寒冷，甚于四逆也。节庵曰、邪在表则手足热，邪在半表半里则
手足温，邪在阴经则手足逆冷。然自热致温，自温至冷，此传经之邪也，轻则四逆散，重则承气汤。若
乃直中阴经之邪，初得病便手足厥冷，轻则理中汤，重则四逆汤。阳厥初有头痛身疼，发热恶寒，喜
冷便秘，谵语，露手扬衣，发渴，脉沈数者，承气汤。阴厥初无头疼身热，惟怕寒战栗，倦卧欲眠，下利清
谷，引衣自盖，脉沈迟者，四逆汤。按四逆散方用柴胡枳实芍药甘草，皆寒冷之物，而治四逆之疾，是
知传经之邪，非虚寒症也，故忌用温热之剂。今将传经、直中两症，分作阴厥、阳厥，则四逆与厥判然
分明矣。
不大便，指的是大便不通畅。这通常是因为热邪积聚在胃中，导致胃土干燥开裂，津液耗损，从而引起大便不通。如果见到口渴、说胡话（谵语）、定时发热（潮热）、自汗出、脉象实大且腹部胀满等症状，应当从三承气汤中选择使用。如果是经过泻下法或发汗法治疗后，大便仍然不通的，这是体内津液枯竭所致，适宜使用蜜导法或猪胆汁导法。如果伴有呕吐症状，说明病邪尚未完全入里进入腑证，虽然具备阳明病的症状，也不可使用攻下法。如果小便颜色清亮，可知病邪不在里而在表，同样不可使用攻下法。如果在疾病初愈时过早进食，因胃气无法正常运行而导致便秘，应根据轻重程度采用消食导滞的方法治疗。如果是病后血虚，导致肠胃干燥涩滞而便秘的，又应根据患者年老体壮的情况采用滋润的方法治疗。
太阳病若下焦有热，小腹部必然胀满，按理应该小便不利，现在反而小便通利，这是蓄血证的确切指征，用抵当汤主治。阳明病出现自汗出，按理发汗后应该小便减少，现在反而通利，说明津液在内枯竭，即使大便干硬，也不可攻下，适宜用蜜导法。少阴病若小便通利的，属于虚寒证，用四逆汤主治。
膀胱是贮存津液的器官，依靠气化作用才能排出尿液。如果热邪积聚在下焦，湿邪蕴结在中焦，气机因受热损伤，凝结而不散，严重时会出现小腹部硬满疼痛，小便闭塞不通的情况。如果饮水过多，或者患中湿发黄症，都应以通利小便为先。如发汗后亡失津液，或阳明病汗出过多，则应禁止使用利小便的方法。
《内经》说：阴虚则小便困难。所谓阴虚，就是阳气必会凑合于阴分。这是因为膀胱受热，所以小便□而不能流利顺畅。
小便频数的情况，是肾与膀胱都虚弱，而有客热侵袭所致。这两经既然虚弱，导致受到客热侵犯，虚弱则不能制约水液，所以导致小便频数。小便频数则水流□，□则小便不畅快，所以表现为频数。
四逆，是指四肢逆冷而不温暖。厥，是指手足寒冷，比四逆更严重。节庵说：邪气在表则手足发热，邪气在半表半里则手足温，邪气在阴经则手足逆冷。然而，由热转温，由温转冷，这是传经之邪的表现，轻症用四逆散，重症用承气汤。如果是直中阴经的邪气，刚得病就手足厥冷，轻症用理中汤，重症用四逆汤。阳厥初期有头痛身疼、发热恶寒、喜冷饮、便秘、说胡话、掀开衣服露出手臂、口渴、脉象沉数等症状，用承气汤。阴厥初期没有头痛身热，只怕寒冷战栗、疲倦想睡、下利清谷（拉出不消化的食物）、拉着衣被自己遮盖、脉象沉迟，用四逆汤。按四逆散的方子，使用柴胡、枳实、芍药、甘草，都是寒凉性质的药物，却用来治疗四逆的病证，由此可知传经之邪并非虚寒证，所以忌讳使用温热药剂。现在将传经和直中两种病症，分别划分为阴厥和阳厥，那么四逆与厥就界限分明了。
Bu Da Bian (Constipation) refers to the inability to pass stool. This is generally caused by heat accumulating in the Stomach, causing the Stomach Earth to dry and crack, consuming body fluids (Jin Ye), thereby leading to constipation. If symptoms such as thirst, delirium (Zhan Yu), tidal fever (Chao Re), spontaneous sweating, a solid pulse, and abdominal fullness are observed, one of the Three Chengqi Decoctions should be selected for use. If constipation persists after purgation or diaphoresis, this indicates exhaustion of internal body fluids; Honey Suppository (Mi Dao) or Pig Bile Suppository (Dan Dao) method is appropriate. If accompanied by vomiting, the pathogen has not fully entered the Fu organs; although Yangming syndrome symptoms are present, attack methods (purgatives) must not be used. If urine is clear, it is known that the pathogen is not in the interior but remains in the exterior, so attack methods must not be used. If food is consumed too early after recovery, and the Stomach Qi fails to transport and transform, leading to constipation, treatment should focus on resolving stagnation based on severity. If blood deficiency follows illness, causing dryness and astringency in the intestines and stomach leading to constipation, nourishing and moistening methods should be applied according to the patient's age and constitution.
In Taiyang syndrome, if there is heat in the Lower Jiao, the lower abdomen will necessarily be full. Normally, urination should be difficult; however, if urination is now free, this is a definitive sign of Blood Stasis (Xue Zheng). Dihuang Tang (Dihuang Decoction) is the primary formula. In Yangming syndrome with spontaneous sweating, sweating should normally lead to reduced urine output; if urination is now free, it indicates exhaustion of internal body fluids. Even if the stool is hard, it must not be attacked with purgatives; Honey Suppository (Mi Dao) method is appropriate. In Shaoyin syndrome, if urination is free, it is a deficiency-cold syndrome; Sini Tang (Sini Decoction) is the primary formula.
The Bladder is the residence of body fluids; it can excrete them only through Qi transformation. If heat accumulates in the Lower Jiao and dampness harbors in the Middle Jiao, Qi is injured by heat, knotting and failing to disperse. In severe cases, this leads to hardness, fullness, and pain in the lower abdomen, and complete obstruction of urination. If excessive water is drunk, or if jaundice due to damp-heat occurs, promoting urination should be prioritized. However, if body fluids are lost after sweating, or if there is excessive sweating in Yangming syndrome, promoting urination is contraindicated.
The Classics state: "Yin deficiency leads to difficulty in urination." Yin deficiency means Yang inevitably encroaches upon it. This is because the Bladder is heated, thus causing urination □ to be unable to flow smoothly.
Frequent urination indicates deficiency of both the Kidney and the Bladder, compounded by invading external heat (Ke Re). Since these two meridians are deficient, they are susceptible to external heat. Deficiency prevents control over water, causing frequency. Frequent urination causes water flow □; □ leads to incomplete emptying/discomfort during urination, hence the frequency.
Si Ni (Four Extremities Cold) refers to the limbs being cold and not warm. Jue (Cold Reversal) refers to cold hands and feet, which is more severe than Si Ni. Jie'an stated: When pathogen is in the Exterior, hands and feet are hot; when in Half-Exterior Half-Interior, hands and feet are warm; when in Yin meridians, hands and feet are cold and reversed. However, progression from heat to warmth, and from warmth to cold, indicates pathogen transmission via meridians. For mild cases, Sini San (Sini Powder) is used; for severe cases, Chengqi Tang is used. If pathogen directly strikes Yin meridians, cold reversal appears immediately upon onset. For mild cases, Lizhong Tang (Lizhong Decoction) is used; for severe cases, Sini Tang is used. For Yang Jue (Yang-type Cold Reversal), initial symptoms include headache, body ache, fever, aversion to cold, preference for cold drinks, constipation, delirium, exposing hands and arms, thirst, and a deep, rapid pulse; Chengqi Tang is used. For Yin Jue (Yin-type Cold Reversal), initial symptoms lack headache and fever, featuring only fear of cold, shivering, fatigue, desire to sleep, diarrhea with undigested food, pulling clothes/blankets to cover oneself, and a deep, slow pulse; Sini Tang is used. The Sini San formula uses Chai Hu (Bupleuri Radix), Zhi Shi (Aurantii Fructus Immaturus), Shao Yao (Paeoniae Radix Alba), and Gan Cao (Glycyrrhizae Radix et Rhizoma), all cold-natured herbs, yet treats Si Ni disease. This proves that transmitted pathogen syndromes are not deficiency-cold, so warm-toning agents are contraindicated. By distinguishing between transmitted and direct-strike syndromes into Yin Jue and Yang Jue, the distinction between Si Ni and Jue becomes clear.