《活人书》云∶无阳则厥，无阴则呕。却言少阴下利，脉微者，与白通汤，利不止，厥逆
无脉，干呕者，白通加猪胆汁汤主之。又云∶膈上有寒痰，干呕者，不可吐，急温之，宜四逆汤
主之。守真云∶呕者，火气上炎之象也，故胃热甚则呕也。又云∶吐酸，肝木之味也，由火实制
金，金，不能平木，肝木日甚，故为吐酸也，则如饮食，则喜酸也。或言酸为寒者，则如酒苦性
热，养于心火，故饮之则令人色赤气粗，脉洪大而数，语涩谵妄，歌唱悲笑，喜
怒如狂，冒昧健忘，烦渴呕吐，皆热证也，其吐必酸，宿热甚明矣。《素问·至真要大论》云
∶诸呕吐酸，暴注下迫，皆属于热。（注云∶内格呕逆噫，食不得人，是火也。）
《活人书》云∶伤寒下利多种，须辨阴阳，勿令差互。大抵伤寒下利多种，须看脉与外
证。下利脉大者，虚也。脉微弱者，为自止。寒毒入胃，脐下必寒，腹胀满，大便黄白，或青，
或黑，或下利清谷。湿毒瓦斯甚，则下利腹痛，大便如脓血，或如烂肉汁也。得之寒毒入胃，四逆
，理中汤、白通汤加附子、四逆汤等。若湿毒下脓血者，桃花汤、地榆汤主之。守真云∶下利脓
血者，如世之谷肉果菜，湿热甚，则自然腐烂溃发化为水，故食于腹中，感人湿热邪气，则自然
化为脓血。其热为赤，热属心火故也。其湿为黄，湿属脾土故也。燥郁为白，属于肺金故也。湿
热甚于肠胃，怫热结也。湿主于痞，以气逆不能宣通，因而以成肠胃之湿也。湿热相兼。盖水火
阴阳寒热，犹权衡也，一高则一下，一盛则一衰，岂能寒热俱盛于肠中，而同为利者乎。若此
之谬，世传多矣，则如热生疮疡。《素问·大奇论》云∶肠 下血，为少阴气不足，搏为阳气乘
之，热在下焦，故下见血也。《素问·阴阳别论》云∶阴结者，
便血一升，（阴主血故也。）再结二升，三结三升。（注云∶二升，谓之再结。三升，谓之三结。）
《素问·至真要大论》云∶大热内结，注泄不止。热宜寒疗，结复须除，以寒药下之，结散利止、则通因通用也。
《活人书》说：没有阳气就会四肢厥冷，没有阴液就会呕吐。又说少阴病下利，脉象微弱的，给予白通汤；如果下利不止，出现四肢厥逆、无脉、干呕的症状，用白通加猪胆汁汤主治。又说：膈上有寒痰导致干呕的，不能用涌吐法，应当紧急温阳，适宜用四逆汤主治。刘守真（刘完素）说：呕吐，是火气上炎的征象，所以胃热严重就会呕吐。又说：吐酸水，是肝木的味道，由于火气实盛制约了肺金，肺金不能平抑肝木，肝木日益亢盛，所以出现吐酸水的症状，此时饮食会喜欢酸味。有人说酸味属于寒证，这就像酒性苦而热，滋养心火，所以饮酒后使人面色红赤、气息粗重、脉象洪大而数、言语不清甚至胡言乱语、唱歌哭笑、喜怒如狂、神志昏蒙健忘、烦躁口渴呕吐，这些都是热证，其呕吐物必然带酸味，宿热非常明显。《素问·至真要大论》说：各种呕吐酸水，突然泄泻且肛门急迫坠胀，都属于热证。（注解说：格拒不通、呕吐逆气、嗳气，食物无法进入，这是火邪所致。）
《活人书》说：伤寒下利有多种情况，必须辨别阴阳，不要弄错混淆。大抵伤寒下利种类很多，必须看脉象和外部证候。下利脉大的，是虚证。脉象微弱的，说明病情将自行停止。寒毒侵入胃中，脐下必定寒冷，腹部胀满，大便呈黄白色，或青色，或黑色，或下利完谷不化。湿毒之气很盛，就会出现下利腹痛，大便像脓血，或者像烂肉汁一样。如果是寒毒入胃引起的，可用四逆汤、理中汤、白通汤加附子、四逆汤等治疗。如果是湿毒导致下脓血的，用桃花汤、地榆汤主治。刘守真说：下利脓血的，就像世间的谷物、肉类、水果和蔬菜，湿热严重时，自然会腐烂溃发化为水，所以食物在腹中，感受人的湿热邪气，自然也会化为脓血。其中血色红赤，是因为热属于心火；黄色浑浊，是因为湿属于脾土；干燥郁结呈现白色，是因为属于肺金。湿热在肠胃中严重，形成郁热结聚。湿主要导致痞塞，因为气机逆乱不能宣通，因而形成肠胃之湿。湿热相互兼夹。大概水火、阴阳、寒热，如同秤杆上的权衡一样，一端高则另一端低，一方盛则另一方衰，怎么能寒热同时在肠中亢盛，而同为下利的呢？像这种谬误，世间流传很多，这就好比热邪产生疮疡。《素问·大奇论》说：肠道出血，是由于少阴气不足，搏结导致阳气乘虚而入，热在下焦，所以下部见血。《素问·阴阳别论》说：阴结证，便血一升，（阴主血的关系），再结二升，三结三升。（注解说：二升，称为再结；三升，称为三结。）《素问·至真要大论》说：大热内结，泄泻不止。热证宜用寒凉药物治疗，结滞必须去除，用寒下药攻逐，结散利止，这就是“通因通用”的方法。
The *Huoren Shu* (Book of Vitality) states: "Absence of Yang leads to Jue (cold extremities); absence of Yin leads to vomiting." It further states that for Shaoyin disease with diarrhea and a faint pulse, Baotong Tang (White Connect Decoction) should be administered. If the diarrhea persists, accompanied by cold extremities, absent pulse, and dry heaving, Baotong Jia Zhuzhi Dan Tang (Baotong Decoction plus Pig Bile Decoction) is the primary treatment. It also states: "For dry heaving caused by cold phlegm in the diaphragm, emesis should not be induced; instead, urgent warming is required, preferably using Sini Tang (Frigid Extremities Decoction)." Liu Shouzhen (Liu Wansu) stated: "Vomiting is a manifestation of Fire Qi flaming upward; thus, severe Stomach Heat causes vomiting." He further stated: "Vomiting sour fluid is the flavor of Liver Wood. This occurs when excessive Fire restricts Lung Metal, preventing it from subduing Liver Wood, causing Liver Wood to become increasingly hyperactive, leading to sour regurgitation and a preference for sour foods during eating. Some claim sourness belongs to Cold, but this is incorrect. Consider wine: its bitter nature is hot, nourishing Heart Fire. Drinking it causes ruddy complexion, coarse breathing, surging and rapid pulse, slurred speech or delirium, singing, laughing or crying, manic anger or joy, mental confusion and forgetfulness, irritability, thirst, and vomiting—all are signs of Heat. The vomit will inevitably be sour, clearly indicating retained Heat." The *Suwen·Zhi Zhen Yao Da Lun* (Plain Questions: The Most Important Questions of Truth) states: "All types of vomiting and sour regurgitation, sudden diarrhea with tenesmus, belong to Heat." (The commentary notes: "Obstruction with vomiting, reverse qi, and belching, where food cannot enter, is due to Fire.")
The *Huoren Shu* states: "There are many types of diarrhea in Shanghan (Cold Damage); one must distinguish between Yin and Yang to avoid errors. Generally, regarding the various types of Shanghan diarrhea, one must examine the pulse and external symptoms. A large pulse with diarrhea indicates deficiency. A faint pulse suggests the condition will stop spontaneously. When Cold Toxin enters the Stomach, there is cold below the umbilicus, abdominal fullness, and stools that are yellowish-white, green, black, or contain undigested food. When Damp-Toxic Qi is severe, diarrhea with abdominal pain occurs, and stools resemble pus and blood or rotten meat juice. For cases caused by Cold Toxin entering the Stomach, treatments include Sini Tang (Frigid Extremities Decoction), Lizhong Tang (Regulate the Middle Decoction), Baotong Tang (White Connect Decoction) with added Fuzi (Prepared Aconite Root), etc. For damp-toxic diarrhea with pus and blood, Taohua Tang (Peach Blossom Decoction) and Diyü Tang (Sanguisorba Decoction) are indicated. Liu Shouzhen stated: "Diarrhea with pus and blood is like grains, meats, fruits, and vegetables in the world; when Damp-Heat is severe, they naturally rot and disintegrate into water. Similarly, food in the abdomen, upon receiving pathogenic Damp-Heat, naturally transforms into pus and blood. The red color is due to Heat belonging to Heart Fire; the yellow turbidity is due to Dampness belonging to Spleen Earth; the dry stagnation appearing white is due to belonging to Lung Metal. Severe Damp-Heat in the intestines and stomach forms constrained Heat. Dampness primarily causes obstruction because Qi rebellion prevents free circulation, thereby forming intestinal Dampness. Dampness and Heat combine. Water and Fire, Yin and Yang, Cold and Heat are like the weights on a balance beam; if one side is high, the other is low; if one is prosperous, the other declines. How can Cold and Heat both flourish in the intestines simultaneously to cause the same diarrhea? Such fallacies are widely circulated in the world, similar to how Heat generates sores and ulcers." The *Suwen·Da Qi Lun* (Plain Questions: Great Anomalies) states: "Intestinal bleeding is due to insufficiency of Shaoyin Qi, where binding allows Yang Qi to invade; Heat in the Lower Jiao results in lower bleeding." The *Suwen·Yin Yang Bie Lun* (Plain Questions: Differentiation of Yin and Yang) states: "In Yin Binding, bleeding of one sheng [unit], [since Yin governs Blood]; two sheng for second binding; three sheng for third binding." (Commentary: "Two sheng is called second binding; three sheng is called third binding.") The *Suwen·Zhi Zhen Yao Da Lun* (Plain Questions: The Most Important Questions of Truth) states: "Severe internal Heat binding causes incessant diarrhea. Heat should be treated with Cold medicines; binding must be removed. Using Cold purgatives disperses the binding and stops the diarrhea; this is the method of 'treating obstruction with unblocking agents' (Tong Yin Tong Yong)."