呕者，声物俱出者也。吐者，无声而但出物者也。故仲景复言干以别之，则呕为有物明矣。干，
犹空也，但空呕而无所出耳。然呕吐俱有物出，较之轻重，则呕
甚于吐。盖表邪传里，里气上逆，故呕吐而水谷不下也。有胃热，脉弦数，口舌烦渴。有胃寒，脉
弦迟，逆冷不食，小便利。有水气，先渴后呕，膈间怔忡。有脓血，喉中腥，奔逆上冲，不须治之，
呕脓尽自愈。是四者，不可不辩。大抵邪半在表，半在里，则多呕吐。及其里热而呕吐者，亦有之。
故经曰∶呕多，虽有阳明证，不可攻之，为其气逆未收敛为实也。设或呕而脉弱，小便复利，身惟
热而见厥者，难治，以其虚寒甚也。
太阳少阳合病，自利而呕，黄芩加半夏生姜汤。
太阳阳明合病，当自利；若不利，但呕，葛根加半夏汤。
伤寒，胸中热，胃中有邪气，腹痛，气逆欲呕吐者，黄连汤。
太阳病，发热汗出，心下烦郁，痞硬不利，呕吐，大柴胡汤。
三阳发热而呕逆，小柴胡汤，呕而渴者，猪苓汤、五苓散。
先呕后渴，此为欲解，宜与水解。先渴后呕而水停心下，赤茯苓汤。
少阴病，又吐，但欲寐，五六日，自利而渴，小便色白，四逆汤加生姜。
少气，或咳或悸，身痛自利，真武汤去附子，加生姜。膈上寒饮，干呕，吐涎
沫，四逆汤。
若吐利，手足厥冷，烦躁甚者，吴茱萸汤。
食谷欲呕者，属阳明也，上同。得汤反剧者，属上焦，橘皮汤，小柴胡汤。似呕，似哕，似喘，
心下愦愦，大橘皮汤。
汗下后关脉迟缓而吐，为胃寒，理中丸。瘥后虚烦呕吐，竹叶石膏汤加生姜汁。屡经汗下，寒
气膈塞，食入即吐，干姜黄芩黄连人参汤。
汗后水药不入口者，四逆、半夏茯苓汤。《金匮要略》曰∶诸呕吐，谷不下，半夏汤。呕吐，
脉滑数，或洪，发热，茅根汤。
呕吐，是指声音和食物同时发出的症状。吐，是没有声音而仅仅排出食物的症状。因此张仲景用“干”字来加以区分，那么呕是有实物排出的情况就很明确了。“干”，如同“空”的意思，只是空作呕而没有东西吐出罢了。然而呕吐都有实物排出，比较其轻重程度，则呕比吐更严重。这是因为表邪传入体内，导致里气上逆，所以出现呕吐且水谷无法下咽的情况。
如果有胃热，表现为脉象弦数，口舌烦躁口渴；如果有胃寒，表现为脉象弦迟，四肢逆冷不想进食，小便通利；如果有水饮停聚，表现为先口渴后呕吐，胸膈间悸动不安；如果有脓血，表现为喉中有腥臭味，气机奔逆上冲，这种情况不需要治疗，待脓血呕尽后自然痊愈。这四种情况，不可不仔细辨别。大抵而言，邪气一半在表、一半在里时，多会出现呕吐。等到里热盛而出现呕吐的，也有这种情况。所以经典中说：呕吐频繁，即使有阳明病的证候，也不可攻下，因为此时气机上逆尚未收敛成实邪。假如呕吐且脉象微弱，小便反而通利，身体仅有发热却出现四肢厥冷的，属于难治之症，因为其虚寒非常严重。
太阳病与少阳病合病，出现自发性腹泻并伴有呕吐，使用黄芩加半夏生姜汤（Huangqin Jia Banxia Shengjiang Tang, Decoction of Scutellaria with Pinellia and Fresh Ginger）。
太阳病与阳明病合病，应当出现自发性腹泻；如果不下泻，仅仅呕吐，使用葛根加半夏汤（Gegen Jia Banxia Tang, Kudzu Root with Pinellia Decoction）。
伤寒病，胸中烦热，胃中有邪气，腹痛，气机上逆想要呕吐的，使用黄连汤（Huanglian Tang, Coptis Decoction）。
太阳病，发热汗出，心下部烦闷郁结，痞塞坚硬且大便不利，伴有呕吐，使用大柴胡汤（Daxiehu Tang, Major Bupleurum Decoction）。
三阳经发热并伴有呕吐逆气，使用小柴胡汤（Xiaochaihu Tang, Minor Bupleurum Decoction）；呕吐且口渴的，使用猪苓汤（Zhuling Tang, Polyporus Decoction）、五苓散（Wuling San, Five-Ingredient Powder with Poria）。
先呕吐后口渴，这是病情将要解除的表现，适宜给予水分以解渴；先口渴后呕吐且水饮停聚在心下的，使用赤茯苓汤（Chifuling Tang, Red Poria Decoction）。
少阴病，又发生呕吐，只想睡觉，病程五六日，出现自发性腹泻且口渴，小便颜色发白，使用四逆汤（Sini Tang, Counterflow Decoction）加生姜。
气短，或者咳嗽或者心悸，身体疼痛且自发性腹泻，使用真武汤（Zhenwu Tang, True Warrior Decoction）去掉附子，加入生姜。膈上有寒饮，干呕，吐出涎沫，使用四逆汤（Sini Tang, Counterflow Decoction）。
如果出现呕吐腹泻，手足厥冷，烦躁严重的，使用吴茱萸汤（Wuzhuyu Tang, Evodia Decoction）。
进食谷物就想呕吐的，属于阳明病，治法同上；服药后反应反而加剧的，属于上焦病变，使用橘皮汤（Jupi Tang, Tangerine Peel Decoction）、小柴胡汤（Xiaochaihu Tang, Minor Bupleurum Decoction）。
似呕吐、似呃逆、似气喘，心下部昏乱不适，使用大橘皮汤（Dajupi Tang, Major Tangerine Peel Decoction）。
经过发汗或攻下治疗后，关部脉象迟缓而呕吐的，属于胃寒，使用理中丸（Lizhong Wan, Regulate the Middle Pill）。
病愈后虚烦呕吐，使用竹叶石膏汤（Zhuye Shigao Tang, Bamboo Leaf and Gypsum Decoction）加生姜汁。多次经过发汗和攻下，寒气阻塞胸膈，食物吃下去就吐出来的，使用干姜黄芩黄连人参汤（Ganjiang Huangqin Huanglian Renshen Tang, Dried Ginger, Scutellaria, Coptis, and Ginseng Decoction）。
发汗后连水药都喝不下去的，使用四逆汤（Sini Tang, Counterflow Decoction）、半夏茯苓汤（Banxia Fuling Tang, Pinellia and Polyporus Decoction）。《金匮要略》说：各种呕吐，食物无法下咽的，使用半夏汤（Banxia Tang, Pinellia Decoction）。呕吐，脉象滑数或洪大，伴有发热，使用茅根汤（Maogen Tang, Imperata Root Decoction）。
Vomiting (Ou) refers to a symptom where both sound and matter are expelled simultaneously. Spitting (Tu) refers to expelling matter without sound. Therefore, Zhang Zhongjing used "gan" (dry/empty) to distinguish them, making it clear that ou involves the expulsion of actual matter. "Gan" is akin to "empty," referring merely to empty retching without any substance being expelled. However, since both vomiting and spitting involve the expulsion of matter, comparing their severity, ou is more severe than tu. This occurs because exterior pathogens transmit inward, causing rebellious qi in the interior, leading to vomiting and an inability to retain food or fluids.
If there is stomach heat, the pulse is wiry and rapid, accompanied by irritability and thirst in the mouth and tongue. If there is stomach cold, the pulse is wiry and slow, accompanied by cold extremities, loss of appetite, and free urination. If there is fluid retention, one experiences thirst followed by vomiting, and palpitations in the epigastric region. If there is pus and blood, there is a fishy odor in the throat and a rushing sensation of qi moving upward; this requires no specific treatment, as it will resolve spontaneously once the pus and blood are vomited out. These four conditions must be carefully differentiated. Generally, when pathogens are half-exterior and half-interior, vomiting often occurs. When interior heat leads to vomiting, this also happens. Thus, the classics state: "Frequent vomiting, even if Yangming syndrome patterns are present, should not be treated with purgation," because the qi is rebellious and has not yet consolidated into excess. If vomiting is accompanied by a weak pulse, free urination, fever only, and cold extremities, it is difficult to treat due to severe deficiency-cold.
In combined Taiyang and Shaoyang disease, with spontaneous diarrhea and vomiting, use Huangqin Jia Banxia Shengjiang Tang (Decoction of Scutellaria with Pinellia and Fresh Ginger).
In combined Taiyang and Yangming disease, spontaneous diarrhea should occur; if there is no diarrhea but only vomiting, use Gegen Jia Banxia Tang (Kudzu Root with Pinellia Decoction).
In Shanghan (Cold Damage), with heat in the chest, pathogenic factors in the stomach, abdominal pain, and rebellious qi causing a desire to vomit, use Huanglian Tang (Coptis Decoction).
In Taiyang disease, with fever, sweating, mental restlessness and oppression in the epigastrium, fullness and hardness with difficult defecation, and vomiting, use Daxiehu Tang (Major Bupleurum Decoction).
For fever and rebellious vomiting involving the three yang channels, use Xiaochaihu Tang (Minor Bupleurum Decoction); for vomiting with thirst, use Zhuling Tang (Polyporus Decoction) and Wuling San (Five-Ingredient Powder with Poria).
Vomiting followed by thirst indicates the condition is resolving; provide water to quench thirst. Thirst followed by vomiting with fluid retention in the heart/lower chest area indicates Chifuling Tang (Red Poria Decoction).
In Shaoyin disease, with vomiting, drowsiness, occurring after five to six days, with spontaneous diarrhea, thirst, and white urine, use Sini Tang (Counterflow Decoction) added with fresh ginger.
For shortness of breath, or cough, or palpitations, body pain, and spontaneous diarrhea, use Zhenwu Tang (True Warrior Decoction) removing Fuzi (Aconite) and adding fresh ginger. For cold-fluid retention above the diaphragm, dry heaving, and spitting of saliva/froth, use Sini Tang (Counterflow Decoction).
If vomiting and diarrhea occur with cold extremities and severe irritability, use Wuzhuyu Tang (Evodia Decoction).
Desire to vomit upon eating grain belongs to Yangming disease, treated as above. If symptoms worsen after taking the decoction, it belongs to the upper jiao; use Jupi Tang (Tangerine Peel Decoction) and Xiaochaihu Tang (Minor Bupleurum Decoction).
Symptoms resembling vomiting, hiccups, or asthma, with a confused and uncomfortable feeling in the epigastrium, use Dajupi Tang (Major Tangerine Peel Decoction).
After sweating or purging treatments, if the guan pulse is slow and vomiting occurs, it is stomach cold; use Lizhong Wan (Regulate the Middle Pill). For post-illness deficiency-heat irritability and vomiting, use Zhuye Shigao Tang (Bamboo Leaf and Gypsum Decoction) added with fresh ginger juice. After repeated sweating and purging, if cold qi blocks the diaphragm and food is vomited immediately upon ingestion, use Ganjiang Huangqin Huanglian Renshen Tang (Dried Ginger, Scutellaria, Coptis, and Ginseng Decoction).
If water and medicine cannot be retained after sweating, use Sini Tang (Counterflow Decoction) and Banxia Fuling Tang (Pinellia and Polyporus Decoction). The *Jingui Yaolue* states: For various types of vomiting where food cannot be retained, use Banxia Tang (Pinellia Decoction). For vomiting with a slippery-rapid or surging pulse, accompanied by fever, use Maogen Tang (Imperata Root Decoction).