伤寒合病者，或两经三经齐病不传者为合病。三阳合病，腹满身重，难以转侧，口中不
仁，谵语遗尿，皆不可汗下。
【清热和表里】白虎汤。
【太阳阳明合病】脉浮而长，大便硬，小便利，其脾为约，脾约丸。恶寒者，升麻葛
根根。不恶寒反恶热，
大便不秘者，白虎汤。不恶寒反恶热，大便秘或谵语者，调胃承气汤。喘而胸满者
不可下，麻黄汤。但呕而不下利，葛根加半夏汤。
【太阳少阳合病】脉浮而弦，胁下硬满，往来寒热，及有余证者，并与小柴胡
汤。自下利者，黄芩汤。呕者，黄芩加半夏生姜汤。
【少阳阳明合病】脉弦而长，因发汗，因利小便，已而胃中燥实，大便难也，调胃
承气汤。脉长自利者为顺，脉滑而数者为负，负者克贼。脉滑而数者有宿食，大承气汤。
伤寒并病者，一经先病，又过一经之传者为并病。又始初二阳合病，后则一阳气盛，
一阳病衰，归并于一经也，故曰并病。
【太阳阳明并病】太阳病发汗，汗出不彻，转属阳明，续自微汗出，不恶寒。若面色
怫郁，痛无常处，是阳明复并回太阳，当再汗之愈，麻黄汤。太阳证未罢，桂枝麻黄各半
汤，微汗之。太阳证罢，但阳明证者，下之，宜大承气汤。
【太阳少阳并病】心下痞而眩，少阳也；颈项，太阳也。若头痛眩冒，时结胸，心下痞
硬，当刺肺俞、肝俞、大椎，慎勿下。
太阳不胜，阳明不负，木相克为顺，负者失也。
少阳脉胜，阳明脉负，是鬼贼相克为逆。
伤寒合病，是指两经或三经同时发病且不发生传变的病症。三阳合病时，患者会出现腹部胀满、身体沉重、难以翻身转侧、口中感觉麻木迟钝（口中不仁）、胡言乱语以及小便失禁等症状，这些情况都不可使用发汗或攻下的治疗方法。【清热和表里】宜用白虎汤。
【太阳与阳明合病】若脉象浮而长，大便干硬，小便通畅，这是脾阴被约束的“脾约”证，宜用脾约丸。若有恶寒症状，宜用升麻葛根汤。若不恶寒反而怕热，且大便不干结的，宜用白虎汤。若不恶寒反而怕热，且大便秘结或出现胡言乱语的，宜用调胃承气汤。若气喘且胸部胀满的，不可使用攻下法，宜用麻黄汤。若仅有呕吐而无腹泻的，宜用葛根加半夏汤。
【太阳与少阳合病】若脉象浮而弦，胁下部位坚硬胀满，出现忽冷忽热的往来寒热症状，以及其他有余之证的，均与小柴胡汤。若伴有自发性腹泻的，宜用黄芩汤。若伴有呕吐的，宜用黄芩加半夏生姜汤。
【少阳与阳明合病】若脉象弦而长，因误用发汗或利小便的方法，导致胃中干燥实热，大便困难的，宜用调胃承气汤。若脉长且伴有腹泻的为顺证；若脉滑而数的为逆证，逆证表示邪气克制正气。若脉滑而数且体内有宿食的，宜用大承气汤。
伤寒并病，是指一经先发病，随后病邪传入另一经的病症。又指起初是两阳经合病，后来其中一阳经的病势旺盛，另一阳经的病势衰退，病邪归并于某一经，所以称为并病。
【太阳与阳明并病】太阳病经过发汗治疗后，汗出得不透彻，病邪转而归属于阳明经，继续出现轻微出汗，且不恶寒。如果面色发红郁滞，疼痛位置不定，这是阳明病邪又回归太阳经，应当再次使用发汗法治疗以痊愈，宜用麻黄汤。如果太阳证尚未消除，可用桂枝麻黄各半汤，通过微微发汗来治疗。如果太阳证已消除，仅存阳明证的，可使用攻下法，宜用大承气汤。
【太阳与少阳并病】心下部痞塞且头晕目眩，属于少阳病；颈项强痛，属于太阳病。如果出现头痛、眩晕昏冒，时常出现结胸，心下部痞塞硬满的症状，应当针刺肺俞穴、肝俞穴和大椎穴，务必谨慎，切勿使用攻下法。
太阳经之气不胜，阳明经之气不负（即不克制），木克土为顺证；所谓“负”，是指失职或失败。少阳脉象胜（亢盛），阳明脉象负（衰弱），这是鬼贼相克，属于逆证。
He Bing (Combined Disease) in Shanghan refers to conditions where two or three meridians are affected simultaneously without transmission. In San Yang He Bing (Combined Disease of the Three Yang Meridians), symptoms include abdominal fullness, heaviness of the body, difficulty in turning over, numbness or insensitivity in the mouth (Kou Zhong Bu Ren), delirium, and urinary incontinence. These conditions are not suitable for treatment with sweating (Fa Han) or purging (Xia) methods. [To Clear Heat and Harmonize Interior and Exterior] Baihu Tang (White Tiger Decoction) is indicated.
[Combined Disease of Taiyang and Yangming] If the pulse is floating and long, with hard stool and free urination, this is Pi Yue (Spleen Constriction), and Pi Yue Wan (Spleen Constriction Pill) is indicated. If there is aversion to cold, Shengma Gegen Tang (Cimicifugae and Puerariae Decoction) is indicated. If there is no aversion to cold but rather aversion to heat, with non-constipated stool, Baihu Tang (White Tiger Decoction) is indicated. If there is no aversion to cold but rather aversion to heat, with constipation or delirium, Tiaowei Chengqi Tang (Regulating the Stomach and Directing Downward Decoction) is indicated. If there is wheezing and chest fullness, purging is contraindicated; Mahuang Tang (Ephedra Decoction) is indicated. If there is vomiting without diarrhea, Gegen Banxia Tang (Pueraria and Pinellia Decoction) is indicated.
[Combined Disease of Taiyang and Shaoyang] If the pulse is floating and wiry, with hardness and fullness under the hypochondrium, alternating chills and fever (Wang Lai Han Re), and other excess symptoms, Xiao Chaihu Tang (Minor Bupleurum Decoction) is indicated. If there is spontaneous diarrhea, Huangqin Tang (Scutellaria Decoction) is indicated. If there is vomiting, Huangqin Banxia Shengjiang Tang (Scutellaria, Pinellia, and Fresh Ginger Decoction) is indicated.
[Combined Disease of Shaoyang and Yangming] If the pulse is wiry and long, resulting from improper sweating or diuresis, leading to dryness and excess in the stomach and difficulty in defecation, Tiaowei Chengqi Tang (Regulating the Stomach and Directing Downward Decoction) is indicated. A long pulse with diarrhea indicates a favorable condition (Shun); a slippery and rapid pulse indicates an unfavorable condition (Fu/Negative), representing pathogenic factors overcoming healthy qi. If the pulse is slippery and rapid with retained food, Dachengqi Tang (Major Directing Downward Decoction) is indicated.
Bing Bing (Consecutive Disease) in Shanghan refers to a condition where one meridian is diseased first, and subsequently, the disease transmits to another meridian. It also refers to an initial combined disease of two Yang meridians, where later one Yang meridian becomes dominant while the other declines, causing the pathology to merge into a single meridian; hence it is called Bing Bing.
[Consecutive Disease of Taiyang and Yangming] After treating Taiyang disease with sweating, if the sweat is incomplete, the condition may transform into Yangming, presenting with continuous slight sweating and no aversion to cold. If the face appears flushed and congested, and pain occurs in various locations without fixed sites, this indicates Yangming pathogen returning to Taiyang, requiring repeated sweating to resolve; Mahuang Tang (Ephedra Decoction) is indicated. If Taiyang symptoms have not subsided, Guizhi Mahuang Ge Ban Tang (Decoction of Half Guizhi and Half Mahuang) is used to induce slight sweating. If Taiyang symptoms have subsided and only Yangming symptoms remain, purging is appropriate; Dachengqi Tang (Major Directing Downoard Decoction) is indicated.
[Consecutive Disease of Taiyang and Shaoyang] Epigastric stuffiness accompanied by dizziness belongs to Shaoyang; stiff neck and occipital pain belong to Taiyang. If headache, dizziness, and vertigo occur, along with occasional Jie Xiong (Chest Binding) and epigastric stuffiness with hardness, acupuncture at Feishu (BL13), Ganshu (BL18), and Dazhui (GV14) is indicated. Purging must be strictly avoided.
If Taiyang Qi is insufficient and Yangming Qi does not overcome it, Wood overcoming Earth is considered favorable (Shun). "Fu" implies failure or loss. If Shaoyang pulse is excessive and Yangming pulse is deficient, this represents Ghost-Thief overcoming, which is unfavorable (Ni).