〔《活》〕半夏桂枝甘草汤治伏气之病，谓非时有暴寒中人，伏气于少阴经，始不觉病，旬月乃发，脉更微弱。
先发咽痛似伤寒，非喉痹之病，必下利，始用半夏桂枝甘草汤主之，此病只二日便瘥，古方谓之肾伤
寒也，次用四逆主之。
半夏桂枝甘草汤
半夏（汤洗） 甘草（炙） 桂心（各等分）
上 咀，每服四钱，水煎候冷，少少细呷之。（即仲景半夏散及汤，但药 咀耳。）
腹满时痛而吐者，太阴病。论见腹满。（《活人》云∶理中汤主之。）
少阴病，欲吐不吐，心烦，但欲寐，自利而渴。（论见下利。《活人》云∶四逆汤主之。）少阴病，
饮食入口则吐，心中温温欲吐，复不能吐，始得之手足寒，脉弦迟者，此胸中实，不可下也，当吐之。
若膈有寒饮，干呕者，不可吐也，急温之，宜四逆汤。少阴病，但欲卧，不烦而吐，五日变自利，
烦躁不得寐者死。（论见但欲寐。）
腹痛欲呕吐者，宜黄连汤。病解后虚羸少气欲吐者，宜竹叶石膏汤。
干呕吐涎沫头痛者，宜吴茱萸汤。
吴茱萸（汤泡洗，一两半） 人参（三分） 生姜（一两半） 大枣（三枚）
上 咀，水煎去渣，分二服。
发热，渴欲饮水，水入则吐者，宜五苓散。（论见厥。）
伤寒本自寒下，医复吐下之，寒格更逆吐下。若食入口即吐，干姜黄连黄芩人参汤主之。
干姜 黄连 黄芩 人参（各等分）
上 咀，水煎温服。
太阳病吐后，汗出不恶寒，发热，关脉细数，欲食冷食，朝食暮吐，此为小逆。（论见发热。）
病患脉数为热，当消谷引食而反吐者，此因发汗，令阳气微，膈气虚，脉乃数也。数而客热者，不能消谷，
以胃中虚冷故也。凡服桂枝汤而吐者，必吐脓血也。（注云∶内热者，服桂枝汤则吐，如酒客之类是也。）
吐厥逆者，甘姜。
[From *Liu Ren Shu*] Banxia Guizhi Gancao Tang (Pinellia, Cinnamon Twig, and Licorice Decoction) treats Fuqi disease (latent qi disease). This refers to sudden cold invading the body out of season, with pathogenic qi lying latent in the Shaoyin meridian (Lesser Yin channel). Initially, no illness is felt; after about a month, it manifests with a pulse that is even more weak and faint.
Initially, there is sore throat resembling Taiyang cold damage (Shanghan), but it is not Hou Bi (sore throat obstruction). There must be diarrhea. At this point, Banxia Guizhi Gancao Tang should be used as the primary treatment. If this disease resolves within two days, ancient formulas call it Kidney Cold Damage (Shen Shang Han). Subsequently, Sini Tang (Frigid Extremities Decoction) should be used.
Banxia Guizhi Gancao Tang (Pinellia, Cinnamon Twig, and Licorice Decoction)
Banxia (Pinelliae Rhizoma, washed with decoction)
Gancao (Glycyrrhizae Radix et Rhizoma, honey-fried)
Guixin (Cinnamomi Cortex, equal parts)
Chop the above herbs. Take 4 qian per dose, decoct in water, wait for it to cool, and sip slowly in small amounts. (This is essentially Zhang Zhongjing's Banxia San Ji Tang [Pinellia Powder and Decoction], except the herbs are chopped rather than crushed.)
Abdominal fullness, intermittent pain, and vomiting indicate Taiyin disease (Greater Yin disease). See the discussion under "Abdominal Fullness". (*Liu Ren Shu* states: Treat with Lizhong Tang [Regulate the Middle Decoction].)
Shaoyin disease (Lesser Yin disease) characterized by the desire to vomit but inability to do so, irritability, only wanting to sleep, spontaneous diarrhea, and thirst. (See the discussion under "Diarrhea". *Liu Ren Shu* states: Treat with Sini Tang [Frigid Extremities Decoction].)
Shaoyin disease where food entering the mouth causes immediate vomiting, a sensation of nausea in the heart without actual vomiting, cold hands and feet at the onset, and a string-taut and slow pulse indicates excess in the chest. Purging is contraindicated; emesis (vomiting therapy) should be induced.
If there is cold-fluid retention in the diaphragm causing dry heaving, emesis is contraindicated. Urgent warming is required; Sini Tang (Frigid Extremities Decoction) is appropriate.
In Shaoyin disease, if the patient only wants to lie down, has no irritability but vomits, and after five days develops spontaneous diarrhea, irritability, and insomnia, the prognosis is fatal. (See the discussion under "Only Wanting to Sleep".)
For abdominal pain with the desire to vomit, Huanglian Tang (Coptis Decoction) is appropriate. For post-illness debility, emaciation, shortness of breath, and desire to vomit, Zhuyegao Shi Tang (Bamboo Leaf and Gypsum Decoction) is appropriate.
For dry heaving, spitting of clear saliva, and headache, Wuzhuyu Tang (Evodia Decoction) is appropriate.
Wuzhuyu Tang (Evodia Decoction)
Wuzhuyu (Evodiae Fructus, soaked and washed in decoction, 1.5 liang)
Renshen (Ginseng Radix et Rhizoma, 3 fen)
Shengjiang (Zingiberis Rhizoma Recens, 1.5 liang)
Dazao (Jujubae Fructus, 3 pieces)
Chop the above herbs, decoct in water, remove the dregs, and divide into two doses.
For fever, thirst with desire to drink water, and vomiting immediately after drinking, Wuling San (Five-Ingredient Powder with Poria) is appropriate. (See the discussion under "Jue" [Cold Extremities].)
In Shanghan (Cold Damage), if there was originally cold-type diarrhea, and the physician incorrectly applied emesis and purgation, cold obstruction leads to aggravated vomiting and diarrhea. If food is vomited immediately upon entering the mouth, Ganjiang Huanglian Huangqin Renshen Tang (Dried Ginger, Coptis, Scutellaria, and Ginseng Decoction) is indicated.
Ganjiang (Zingiberis Rhizoma)
Huanglian (Coptidis Rhizoma)
Huangqin (Scutellariae Radix)
Renshen (Ginseng Radix et Rhizoma) (Equal parts)
Chop the above herbs, decoct in water, and take warm.
After vomiting in Taiyang disease (Greater Yang disease), if sweating occurs without aversion to cold, accompanied by fever, a fine and rapid guan pulse, desire for cold food, and morning intake with evening vomiting, this is considered a minor deviation (Xiao Ni). (See the discussion under "Fever".)
A rapid pulse indicates heat, which should lead to digestion of food and increased appetite. If vomiting occurs instead, it is because sweating caused slight yang deficiency and empty qi in the diaphragm, resulting in a rapid pulse. A rapid pulse with exogenous heat cannot digest food due to cold deficiency in the stomach. Generally, those who vomit after taking Guizhi Tang (Cinnamon Twig Decoction) will vomit pus and blood. (Note: Those with internal heat, such as habitual drinkers, will vomit after taking Guizhi Tang.)
For vomiting leading to Jue Ni (cold extremities reversal), use Gan Jiang (Dried Ginger).