内经曰。其高者。因而越之。其下者。引而竭之。中满者。泻之于内。其有邪者。渍形以
为汗。其在皮者。汗而发之。治伤寒之妙。虽有变通。终不越此数法也。伤寒邪气自
表而传里。留于胸中。为邪在高分。则可吐之。是越之之法也。所吐之证。亦自不同。
如不经汗下。邪气蕴郁于膈。则谓之膈实。应以瓜蒂散吐之。瓜蒂散吐胸中实邪
者也。若发汗吐下后。邪气乘虚留于胸中。则谓之虚烦。应以栀子豉汤吐之。栀子
豉汤。吐胸中虚烦者也。栀子味苦寒。内经曰。酸苦涌泄为阴。涌者吐之也。涌吐虚
烦。必以苦为主。是以栀子为君。烦为热胜也。涌热者。必以苦。胜热者。必以寒。香豉
味苦寒。助栀予以吐虚烦。是以香豉为臣。内经曰。气有高下。病有远近。证有中外。
治有轻重。适其所以为治。根据而行之。所谓良矣。
栀子（君十四枚擘） 香豉（臣四合绵裹）
上二味。以水四升。煮栀子。取二升半。去渣内豉。更煮取一升半。去渣分二服。温
进一服。得快吐者。止后服。
华佗曰。四日在胸。则可吐之。此迎而夺之之法也。千金方曰。气浮上部。填塞心胸。
胸中满者。吐之则愈。此随证治之之法也。大约伤寒四五日。邪气客于胸中之时
也。加之胸中烦满。气上冲咽喉。不得息者。则为吐证具。乃可投诸吐药。而万全之
功有之矣。瓜蒂味苦寒。内经曰。湿气在上。以苦吐之。寒湿之气。留于胸中。以苦为
主。是以瓜蒂为君。赤小豆味酸涩。内经曰。酸苦涌泄为阴。分涌膈实。必以酸为佐。
是以赤小豆为臣。香豉味苦寒。苦以涌泄。寒以胜热。去上膈之热。必以苦寒为辅。
是以香豉为使。酸苦相合。则胸中痰热涌吐而出矣。其于亡血虚家。所以不可与
者。以瓜蒂散为峻剂。重亡津液之药。亡血虚家。补养则可。更亡津液。必不可全。用
药君子。必讲究焉。
瓜蒂（君一分熬黄） 赤小豆（臣一分）
上二味。各别捣筛为散。已合治之。取一钱七。以香豉一合。用熟汤七合。煮作稀
糜。去渣取汁。和散温顿服之。不吐者少少加。得快吐乃止。诸亡血虚家。不可与
瓜蒂散。
《黄帝内经》说：病位在上部的，采用涌吐的方法使邪气排出；病位在下部的，采用通利二便的方法使邪气排尽；中焦痞满胀实的，从内部进行泻下；体内有邪气的，通过浸渍身体来发汗；邪气在体表的，通过发汗来驱散。治疗伤寒的奥妙，虽然有所变通，但终究离不开这几类方法。
伤寒邪气从体表传入体内，停留在胸中，这属于邪气位于高位，可以采用吐法。这就是“因而越之”的方法。所适用的吐证情况也不尽相同。例如，没有经过发汗或泻下治疗，邪气郁结在膈间，这就称为“膈实”，应当使用瓜蒂散进行吐治。瓜蒂散是用来吐出胸中的实邪的。如果经过发汗、催吐或泻下治疗后，邪气乘虚停留在胸中，这就称为“虚烦”，应当使用栀子豉汤进行吐治。栀子豉汤是用来吐出胸中因虚热引起的烦闷的。
栀子的味道苦、性寒。《内经》说：“酸味和苦味具有涌泄作用，属于阴。”所谓“涌”，就是催吐的意思。要涌吐虚烦，必须以苦味药为主，所以用栀子作为君药。烦闷是由于热盛所致。要涌泄热邪，必须用苦味药；要克制热邪，必须用寒性药。香豉的味道苦、性寒，能辅助栀子涌吐虚烦，所以用香豉作为臣药。《内经》说：气机有高下之分，疾病有远近之别，证候有内外之异，治疗有轻重之度。只要适合治疗的需要，遵循规律而行，就是良法了。
【方剂组成】栀子（君药，十四枚，掰开） 香豉（臣药，四合，用绵布包裹）
以上两味药，用水四升，先煮栀子，取汁二升半，去掉药渣，加入香豉，再煮取汁一升半，去掉药渣，分两次服用，温服一次。如果能迅速引起呕吐，就停止服用剩下的药液。
华佗说：邪气在第四天进入胸中，就可以采用吐法。这是迎头痛击、夺其邪气的治疗方法。《千金方》说：气浮于上部，填塞心胸，导致胸中胀满的，采用吐法就能痊愈。这是随证施治的治疗方法。一般来说，伤寒发病四五日，是邪气客居胸中的时候。再加上胸中烦闷胀满，气向上冲至咽喉，呼吸不畅的，就具备了使用吐法的指征，此时投用各种吐药，才能万无一失。
瓜蒂的味道苦、性寒。《内经》说：“湿气在上部，用苦味药吐之。”寒湿之气停留在胸中，以苦味药为主，所以用瓜蒂作为君药。赤小豆的味道酸、涩。《内经》说：“酸味和苦味具有涌泄作用，属于阴。”要分消膈间的实邪，必须以酸味药为佐助，所以用赤小豆作为臣药。香豉的味道苦、性寒，苦味能涌泄，寒性能胜热，去除上膈的热邪，必须以苦寒药为辅，所以用香豉作为使药。酸味和苦味相结合，胸中的痰热就会涌吐而出。对于失血患者和体质虚弱的人，之所以不能使用此方，是因为瓜蒂散是峻猛之剂，会严重耗伤津液。失血和体质虚弱的人，应当补养，如果再耗伤津液，必然无法保全生命。用药的君子，一定要仔细研究。
【方剂组成】瓜蒂（君药，一分，炒至黄色） 赤小豆（臣药，一分）
以上两味药，分别捣碎过筛成散剂，混合均匀。取一钱七分散剂，用香豉一合，熟水七合，煮成稀粥状，去掉药渣取汁，将散剂调入其中，温服一次。如果不呕吐，逐渐增加剂量，直到引起快速呕吐为止。所有失血和体质虚弱的人，禁止服用瓜蒂散。
The *Huangdi Neijing* (Yellow Emperor's Inner Canon) states: "For pathogens located in the upper region, induce vomiting to expel them; for those in the lower region, drain them through urination or defecation; for fullness in the middle, purge from within; for pathogens in the body, soak the form to induce sweating; for pathogens in the skin, disperse them through sweating." The subtlety of treating *Shanghan* (Cold Damage) involves flexibility, but ultimately does not exceed these few methods.
When pathogenic factors of *Shanghan* transmit from the exterior to the interior and remain in the chest, this constitutes pathogens at a high position, and thus emesis may be employed. This is the method of "inducing vomiting to expel" (*Yin Er Yue Zhi*). The indications for emesis vary. For instance, if no sweating or purgation has been performed, and pathogenic factors are constrained and stagnant in the diaphragm, it is termed "Diaphragmatic Excess" (*Ge Shi*), which should be treated with *Gua Di San* (Melon Seed Powder) to induce vomiting. *Gua Di San* is used to expel excess pathogens from the chest. If, after sweating, vomiting, or purging, pathogenic factors take advantage of the deficiency to remain in the chest, it is termed "Deficiency Irritability" (*Xu Fan*), which should be treated with *Zhizi Chi Tang* (Gardenia and Fermented Soybean Decoction) to induce vomiting. *Zhizi Chi Tang* is used to expel the irritability caused by deficiency-heat in the chest.
Zhi Zi (Fructus Gardeniae) is bitter and cold. The *Neijing* states: "Sour and bitter flavors have the effect of surging and draining, belonging to Yin." "Surging" refers to inducing vomiting. To surge and drain deficiency-irritability, one must primarily use bitter substances; therefore, Zhi Zi is used as the Sovereign herb (Jun). Irritability results from excessive heat. To surge and drain heat, bitter substances are required; to overcome heat, cold substances are required. Xiang Chi (Fermented Soybean) is bitter and cold, assisting Zhi Zi in vomiting out deficiency-irritability; therefore, Xiang Chi is used as the Minister herb (Chen). The *Neijing* states: "Qi has high and low positions; diseases have distant and near origins; syndromes have internal and external locations; treatments have light and heavy degrees." One must apply treatment appropriately according to the situation, following the principles, which constitutes good practice.
[Prescription Composition] Zhi Zi (Sovereign, 14 pods, broken open); Xiang Chi (Minister, 4 he, wrapped in silk cloth).
Take the above two ingredients, add four sheng of water, boil Zhi Zi until half of the water remains (2.5 sheng), remove the dregs, add Xiang Chi, and boil again until 1.5 sheng remains. Remove the dregs and divide into two doses. Take one dose warm. If rapid vomiting occurs, stop taking the remaining dose.
Hua Tuo stated: "On the fourth day, when pathogens enter the chest, emesis can be applied." This is the method of "meeting and seizing" (attacking the pathogen directly). The *Qianjin Fang* states: "When qi floats to the upper part, filling and blocking the heart and chest, causing chest fullness, emesis will cure it." This is the method of treating according to the syndrome. Generally, on the fourth or fifth day of *Shanghan*, this is when pathogens lodge in the chest. Additionally, if there is chest irritability and fullness, qi rushing up to the throat, and difficulty breathing, the indications for emesis are complete. At this point, administering various emetic drugs can ensure a perfect outcome.
Gua Di (Fructus Momordicae) is bitter and cold. The *Neijing* states: "Dampness in the upper region is treated with bitter emetics." Cold-dampness staying in the chest requires bitter substances as the primary agent; therefore, Gua Di is used as the Sovereign herb. Chi Xiao Dou (Semens Phaseoli Angularis) is sour and astringent. The *Neijing* states: "Sour and bitter flavors have the effect of surging and draining, belonging to Yin." To separate and drain diaphragmatic excess, sour substances must be used as Assistant herbs (Zuo); therefore, Chi Xiao Dou is used as the Minister herb. Xiang Chi is bitter and cold; bitterness induces surging and draining, and cold overcomes heat. To remove heat from the upper diaphragm, bitter-cold substances are necessary as Auxiliary herbs (Shi); therefore, Xiang Chi is used as the Envoy herb. When sour and bitter flavors combine, phlegm-heat in the chest will be surged and vomited out. For patients who have lost blood or are constitutionally deficient, this formula is contraindicated because *Gua Di San* is a harsh agent that severely depletes body fluids. Such patients require nourishment; further depletion of fluids would inevitably lead to failure to recover. Practitioners must study this carefully.
[Prescription Composition] Gua Di (Sovereign, 1 fen, roasted until yellow); Chi Xiao Dou (Minister, 1 fen).
The above two ingredients are separately pounded and sifted into powder, then mixed thoroughly. Take 1 qian 7 fen of the powder. Use 1 he of Xiang Chi and 7 he of boiled water, cook into a thin porridge, remove the dregs to obtain the juice, mix with the powder, and take warm in one dose. If vomiting does not occur, increase the dose slightly. Stop once rapid vomiting is achieved. All patients with blood loss or constitutional deficiency must not take *Gua Di San*.