吴又可曰∶时疫有始终能食者，邪不传胃也，慎勿绝其饮食，此不呕者也。愚尝见时疫初起未发热时，表证未
见，有先作呕数日者，此疫邪先犯太阴。当辨其口气，无臭气而不粘者，属太阴寒证；有臭气粘浓者，属太阴疫
证。此为先里而后表，不可遽用清凉，闭遏邪气，致使不能透达传化。虽四肢有时厥逆，脉有时沉伏，亦不可用温
热，致增呕证。甚有舌紫昏沉者，惟当宣其胃气，藿香正气散最宜。若已发热而呕者，吴氏达原饮加半夏。兼三阳
表证加羌活、葛根、柴胡。若呕而烦渴，身热而不恶寒者，邪在阳明也，白虎汤、黄芩汤、并加半夏。若呕而舌
黄，胸中有满痛处，桔皮半夏汤加枳实、山楂、麦芽、川贝。贝母力缓，用至五钱或一两，乃能舒郁散结。若呕而
舌黄，心下脐上有满痛拒按者，大柴胡汤。若呕而舌黄或黑，少腹有满痛拒按，当视其前后何部不利。大便不利调
胃承气汤；小便不利四苓加木通，或益元散，利之则愈。寒热已解，二便通利，胸腹无滞而呕不止者，余热在胃
也，竹叶石膏汤。屡经清、下，呕不止而舌无苔，多汗、心悸、萎倦者，中气伤也，大半夏汤或六君子汤加白蔻。
屡经清、下，倦怠异常，四肢渐冷者，乃清下太过而中寒
也，理中汤甚至加附子。然此为治药之法，非治疫之法也，宜详察之
吴又可说：在时行疫病中，有从发病到痊愈始终能够进食的，这是因为病邪没有传入胃腑，千万不要禁止其饮食，这类情况通常不会出现呕吐。我曾见到时行疫病初起、尚未发热时，表证还未显现，却先出现连续几天呕吐的症状，这是疫邪先侵犯了太阴经。应当辨别患者口中的气味：如果口中有异味但不粘腻浑浊的，属于太阴寒证；如果有臭气且口气粘腻浓浊的，属于太阴疫证。这种情况属于病邪先在体内（里），然后才表现于体表（表），不可急于使用清凉药物，以免遏制病邪，导致病邪无法透发和传化。虽然有时会出现四肢厥冷、脉搏沉伏的情况，也不可使用温热药物，以免加重呕吐症状。更有甚者出现舌质紫暗、神志昏沉的，只应当宣通胃气，藿香正气散最为适宜。如果已经发热并且呕吐的，用吴氏达原饮加入半夏。如果兼有三阳经的表证，加入羌活、葛根、柴胡。如果呕吐且心烦口渴，身体发热而不怕冷的，说明病邪在阳明经，可用白虎汤、黄芩汤，并加入半夏。如果呕吐且舌苔发黄，胸中有胀满疼痛的部位，用桔皮半夏汤加入枳实、山楂、麦芽、川贝母。贝母的力道较缓，需用至五钱或一两，才能舒展郁结、消散结滞。如果呕吐且舌苔发黄，心窝部及脐上有胀满疼痛且拒绝按压的，用大柴胡汤。如果呕吐且舌苔发黄或发黑，小腹部有胀满疼痛且拒绝按压的，应当观察前阴（小便）和后阴（大便）哪一部分不通利。大便不通利的，用调胃承气汤；小便不通利的，用四苓散加木通，或者益元散，通过利小便的方法治疗即可痊愈。如果寒热症状已经解除，大小便通畅，胸腹部没有积滞但呕吐仍不止的，是余热留在胃中，用竹叶石膏汤。经过多次清热、攻下治疗后，呕吐仍不止且舌面无苔，多汗、心悸、精神萎靡疲倦的，是中气受损，用大半夏汤或六君子汤加入白豆蔻。经过多次清热、攻下治疗后，倦怠异常，四肢逐渐变冷的，是因为清热攻下过度导致中焦虚寒，用理中汤，甚至加入附子。然而，这些是针对误治后的补救方法，并非治疗疫病的正法，应当仔细审察。
Wu Youke stated: In the context of seasonal epidemics (Shi Yi), there are cases where patients can eat from onset to recovery; this indicates that the pathogenic factor has not transmitted to the Stomach. One must not restrict their diet, as these cases typically do not involve vomiting. I have observed that in the early stage of a seasonal epidemic, before fever appears and when exterior symptoms are absent, some patients experience vomiting for several days first. This occurs because the epidemic pathogen initially attacks the Taiyin channel. One should distinguish based on breath odor: if the breath is odorous but not sticky or turbid, it belongs to a Taiyin Cold pattern; if there is a foul odor accompanied by sticky and thick saliva/breath, it belongs to a Taiyin Epidemic pattern. This represents a condition where the interior is affected first, followed by the exterior. One must not hastily use cooling medications, which would suppress the pathogen and prevent its penetration and transformation. Although there may be instances of cold limbs (Jue Ni) and deep, hidden pulses, one must not use warming and hot medications, as this would exacerbate the vomiting. In severe cases presenting with a purple tongue and lethargy/coma, the treatment should focus on ventilating the Stomach Qi; Huoxiang Zhengqi San (Patchouli Powder to Rectify the Qi) is most suitable. If fever has already appeared along with vomiting, Wu's Daren Yin (Origin-Removing Decoction) with added Banxia (Pinelliae Rhizoma) should be used. If exterior symptoms of the Three Yang channels are present, add Qianghuo (Notopterygii Rhizoma et Radix), Gegen (Puerariae Lobatae Radix), and Chaihu (Bupleuri Radix). If vomiting is accompanied by irritability and thirst, with body heat but no aversion to cold, the pathogen is in the Yangming channel; Baihu Tang (White Tiger Decoction) or Huangqin Tang (Scutellaria Decoction) with added Banxia should be used. If vomiting is accompanied by a yellow tongue coating and distending pain in the chest, Jupi Banxia Tang (Tangerine Peel and Pinellia Decoction) with added Zhishi (Aurantii Fructus Immaturus), Shanzha (Crataegi Fructus), Maiya (Hordei Fructus Germinatus), and Chuanbeimu (Fritillariae Cirrhosae Bulbus) should be used. Beimu (Fritillariae Bulbus) has a mild action; a dose of five qian or one liang is required to soothe depression and dissipate nodules. If vomiting is accompanied by a yellow tongue coating, and there is distending pain with tenderness upon pressure in the epigastrium and above the umbilicus, Da Chaihu Tang (Major Bupleurum Decoction) should be used. If vomiting is accompanied by a yellow or black tongue coating, and there is distending pain with tenderness upon pressure in the lower abdomen, one must examine whether the anterior (urination) or posterior (defecation) orifices are obstructed. If defecation is difficult, Tiaowei Chengqi Tang (Regulate the Stomach and Direct Downward Decoction) is indicated; if urination is difficult, Siling San (Four-Powder Powder) with Mutong (Akebiae Caulis) or Yiyuan San (Benefit the Origin Powder) should be used; promoting diuresis will lead to recovery. If chills and fever have resolved, bowel and bladder movements are unobstructed, and there is no stagnation in the chest and abdomen, yet vomiting persists, this indicates residual heat remaining in the Stomach; Zhuye Shigao Tang (Bamboo Leaf and Gypsum Decoction) should be used. If after repeated clearing and purging treatments, vomiting persists, the tongue lacks coating, and there is profuse sweating, palpitations, and lassitude, this indicates damage to the Middle Qi; Dabanxia Tang (Major Pinellia Decoction) or Liujunzi Tang (Six-Gentlemen Decoction) with added Baicou (Amomi Fructus Rotundus) should be used. If after repeated clearing and purging treatments, there is extreme fatigue and gradual coldness of the four limbs, this is due to excessive clearing and purging causing Cold in the Middle Jiao; Lizhong Tang (Regulate the Middle Decoction), possibly with added Fuzi (Aconiti Lateralis Radix Praeparata), should be used. However, these are methods for treating iatrogenic errors, not the standard method for treating epidemics; careful observation is required.