戴氏云∶恶心者，无声无物，心中欲吐不吐，欲呕不呕，气至咽而复转，如人畏怕，
心中兀兀不自宁也。
虽曰恶心，实非心病，皆胃口之病也。宜用生姜为君，生姜大能开胃口豁痰。
丹溪云∶恶心证多是胃中有火有痰有虚，宜六君子汤加姜汁黄连之类。亦有胃受寒
而恶心者，宜用丁香、理中之属。
大半夏汤 治胃中痰火恶心。
半夏 茯苓 陈皮（各等分）
水盏半、姜七片，煎八分，食后服。
小半夏茯苓汤
半夏（三钱） 茯苓（二钱）
水盏半、姜七片，煎八分，或入姜汁，和入煎一二沸，热服。
理中汤 治胃中虚寒作恶。（方见脾胃门。）
（《内经》名噫气俗作嗳气，今从之，即饱气有声出是也。）
《内经》曰∶心为噫。又云∶太阳所谓上走心为噫者，阴盛而上走于阳明，阳明络
属心为噫，故曰上走心为噫也。
又曰∶二阳一阴发病，主惊骇背痛，善噫善欠也。
曰∶少阴之复，噫哕是也。（此热伤心之所致也。）又曰∶太阳司天，寒淫所胜善噫。
又曰∶太阳之复，唾出清水，及为哕噫是也。（此寒伤心之所致也。）
丹溪曰∶嗳气为胃中有痰有火。春甫谓嗳气多是胃气不和，窒塞不通则嗳气。何以
见之？凡人食饱后多有嗳气，由饮食饱则胃不舒畅而致然也。噫气苦非食后，则为胃虚
而不和。丹溪谓痰与火，特一端耳，医者察之。
戴氏说：所谓恶心，是指没有声音也没有呕吐物，心中想要吐却吐不出来，想要呕却呕不出来，气冲到咽喉处又折返，就像人感到害怕时，心中慌乱不安的样子。
虽然称为恶心，但实际上并不是心脏的疾病，都是胃部的疾病。适宜用生姜作为主药，生姜非常能够开通胃口、豁除痰浊。
丹溪说：恶心证大多是因为胃中有火、有痰、有虚损，适宜使用六君子汤加入姜汁、黄连之类的药物。也有因为胃受寒邪而导致恶心的，适宜使用丁香、理中汤一类的方剂。
大半夏汤：治疗胃中痰火引起的恶心。
半夏、茯苓、陈皮（各取等量）
用水一盏半，生姜七片，煎煮至八分满，饭后服用。
小半夏茯苓汤
半夏（三钱）、茯苓（二钱）
用水一盏半，生姜七片，煎煮至八分满；或者加入姜汁，与药液一起再煮沸一二分钟，热服。
（《内经》中称为“噫气”，世俗写作“嗳气”，现在沿用世俗写法，即饱食后气体有声地排出。）
《内经》说：心会产生噫气。又说：太阳经的病证之所以出现向上走到心脏产生噫气的情况，是因为阴气过盛而向上走行至阳明经，阳明的络脉归属于心从而产生噫气，所以说向上走到心脏产生噫气。
又说：二阳（阳明）与一阴（厥阴）发病，主要表现为惊骇、背痛，容易打嗝（噫）和呵欠。
又说：少阴经的复气（报复之气），表现为噫气和呃逆。（这是热邪损伤心脏所致。）又说：当太阳司天之时，寒气过度盛行，容易导致噫气。
又说：太阳经的复气，表现为吐出清水，以及发生呃逆和噫气。（这是寒邪损伤心脏所致。）
丹溪说：嗳气是因为胃中有痰、有火。春甫认为嗳气多是胃气不和，气机窒塞不通畅所以导致嗳气。凭什么这样知道呢？大凡人在吃饱饭后多有嗳气，这是因为饮食过饱导致胃气不舒畅从而引起这种现象。如果噫气并非发生在食后，那就是因为胃虚而不调和。丹溪所说的痰与火，只是其中一种情况罢了，医生们应当仔细考察。
Dai stated: "Nausea" (E Xin, nausea) refers to a state where there is no sound and no vomitus; the heart feels like wanting to vomit but cannot, or wants to retch but cannot. The Qi rises to the throat and then turns back, resembling the feeling of fear, with the heart feeling unsettled and uneasy.
Although it is called "nausea," it is actually not a disease of the Heart, but rather a disease of the Stomach. It is appropriate to use Shengjiang (Zingiberis Rhizoma Recens, Fresh Ginger) as the sovereign herb, as Shengjiang is highly effective in opening the Stomach appetite and resolving phlegm.
Danxi stated: "Nausea" syndromes are mostly due to Fire, Phlegm, and Deficiency within the Stomach. It is appropriate to use Liujunzi Tang (Six Gentlemen Decoction) added with Jiangzhi (Ginger Juice) and Huanglian (Coptidis Rhizoma), among others. There are also cases where the Stomach is affected by Cold leading to nausea; in such cases, it is appropriate to use Dingxiang (Caryophylli Flos, Clove) and Lizhong Tang (Regulate the Middle Decoction), among others.
Banxia Houpo Tang (Pinellia and Magnolia Bark Decoction): Treats nausea caused by Phlegm-Fire in the Stomach.
Banxia (Pinelliae Rhizoma, Pinellia Tuber), Fuling (Poria, Poria Cocos), Chenpi (Citri Reticulatae Pericarpium, Tangerine Peel) (in equal parts).
Decoct with one and a half cups of water and seven slices of Shengjiang (Fresh Ginger) until reduced to eight-tenths volume; take after meals.
Xiao Banxia Fuling Tang (Minor Pinellia and Poria Decoction)
Banxia (Pinelliae Rhizoma, Pinellia Tuber) (3 qian), Fuling (Poria, Poria Cocos) (2 qian).
Decoct with one and a half cups of water and seven slices of Shengjiang (Fresh Ginger) until reduced to eight-tenths volume; or add Jiangzhi (Ginger Juice), boil together for one or two more boils, and take hot.
Lizhong Tang (Regulate the Middle Decoction): Treats nausea caused by Deficiency-Cold in the Stomach. (Formula see in the Spleen and Stomach section.)
(Note: In *Neijing*, this is named Yi Qi (Belching); commonly written as Ai Qi (Belching). We follow the common usage here, which refers to the sound of gas exiting after fullness.)
*Neijing* states: The Heart produces Yi Qi (Belching). It also says: Regarding Taiyang (Greater Yang) conditions, when the pathogen moves upward to the Heart causing Yi Qi (Belching), it is because Yin is excessive and moves upward to Yangming (Yang Brightness). Since the Yangming collaterals connect to the Heart, Yi Qi (Belching) occurs; thus it is said that moving upward to the Heart causes Yi Qi (Belching).
It also states: When Er Yang (Two Yangs, referring to Yangming) and Yi Yin (One Yin, referring to Jueyin) are diseased, the main manifestations include fright, back pain, frequent Yi Qi (Belching), and frequent yawning.
It states: The returning qi (Fu Qi) of Shaoyin (Lesser Yin) manifests as Yi Qi (Belching) and Hiccups. (This is caused by Heat damaging the Heart.) It also states: When Taiyang (Greater Yang) governs the year, if Cold is excessively prevalent, it leads to Yi Qi (Belching).
It also states: The returning qi (Fu Qi) of Taiyang (Greater Yang) manifests as spitting clear fluid, as well as Hiccups and Yi Qi (Belching). (This is caused by Cold damaging the Heart.)
Danxi stated: Ai Qi (Belching) is due to Phlegm and Fire in the Stomach. Chunfu believes that Ai Qi (Belching) is mostly due to Disharmony of Stomach Qi, where obstruction and lack of free flow cause belching. How do we know this? Generally, people often experience Ai Qi (Belching) after eating a full meal, because overeating causes the Stomach Qi to be uncomfortable, leading to this phenomenon. If Yi Qi (Belching) does not occur after eating, it is due to Stomach Deficiency and Disharmony. Danxi's mention of Phlegm and Fire is merely one aspect; physicians should observe carefully.