夫古之黄连解毒、三黄、凉膈、泻心等剂，非古人之好用凉药也，以其所秉者浓，故用之无寒
中之患，而获败火之功。今人所秉者薄，既不逮古，而又兼之
以凿丧，若用大苦大寒之剂，其何以当之。况瘟疫之火，因邪而生，邪散而火自退矣。若用大寒
之剂，直折其火，未有驱邪之能，而先受寒凉之祸。受寒则表里凝滞，欲求其邪之解也难矣。总之
如黄连、黄柏、龙胆草、苦参大苦大寒等药，皆当慎用。以有生地、二冬、元参、丹皮、栀子、
黄芩、银花、犀角、茅根、竹沥、童便、葛根、石膏、人中黄辈加减出入，足以泻火而有余矣。
如果有真知灼见，非黄连等药不可，少者分计，多者钱计而止，不可多用。
或曰大苦大寒之剂既在禁例，而治瘟疫顾用三承气、白虎何也？答曰∶石膏虽大寒，但阴中
有阳，其性虽凉而能散，辛能出汗解肌，最逐温暑烦热，生津止渴，甘能缓脾，善祛肺与三焦之
火，而尤为阳明经之要药。凡阳狂、斑黄、火逼血升、热深、便秘等症，皆其所宜。唯当或 或
生，视病之轻重而用之耳。大黄虽大寒有毒，然能推陈致新，走而不守。瘟疫阳狂、斑黄、谵语、
燥结、血郁，非此不除。生恐峻猛，熟用为佳。至于芒硝，虽属劫剂，但本草尚称其有却热疫之
长，而软坚
破结非此不可，但较诸石膏、大黄，用之盒饭审慎矣。夫以大黄、石膏之功能，彰彰若是，较之
只有寒凉凝滞之性者，其宜否不大相径庭也哉！此治瘟疫者之所不可阙也欤。
古代的黄连解毒汤、三黄汤、凉膈散、泻心汤等方剂，并非古人喜欢使用寒凉药物，而是因为古人的体质禀赋浓厚，所以使用这些药物没有导致中焦受寒的祸患，反而能获得清败实火的功效。现在人的体质禀赋薄弱，既不如古人，又加上生活起居耗损精气，如果使用大苦大寒的药物，身体怎能承受得住呢？况且瘟疫的火邪，是因外邪侵袭而产生的，外邪消散后火邪自然消退。如果使用大寒的方剂，直接折损火势，却没有驱除邪气的能力，反而先遭受寒凉药物的伤害。受到寒凉则表里之气凝滞不通，想要解除邪气就困难了。总之，像黄连、黄柏、龙胆草、苦参等大苦大寒的药物，都应当谨慎使用。如果有生地黄、天冬、麦冬、玄参、牡丹皮、栀子、黄芩、金银花、犀角、白茅根、竹沥、童便、葛根、石膏、人中黄这类药物进行加减变化，足以有余地地清泻火邪了。如果确实有真知灼见，认为非用黄连等药不可，用量少的以分计算，多的以钱计算为止，不可多用。
有人问：大苦大寒的方剂既然在禁忌之列，那么治疗瘟疫为何还要用三承气汤、白虎汤呢？回答说：石膏虽然性大寒，但阴中有阳，其性质虽凉却能发散，辛味能发汗解肌，最擅长驱逐温暑引起的烦热，生津止渴，甘味能缓和脾急，善于祛除肺与三焦的火邪，尤其是阳明经的要药。凡是阳狂、斑疹发黄、火逼血升、热深、便秘等症状，都是它适宜治疗的。只应当根据病情轻重斟酌使用生石膏或煅石膏。大黄虽然性大寒且有微毒，然而能推陈致新，走而不守。瘟疫出现的阳狂、斑疹发黄、谵语、燥结、血郁等症状，不用此药不能消除。唯恐药性峻猛，用熟大黄为佳。至于芒硝，虽然属于劫夺之剂，但本草尚且称赞它有退却热疫的长处，而软化坚积、破除结聚非它不可，只是相比石膏、大黄，使用时应当更加审慎了。凭借大黄、石膏的功能，如此显著，与那些只有寒凉凝滞性质的药物相比，它们的适宜与否不是大不相同吗！这是治疗瘟疫者所不可缺少的啊。
The ancient formulas such as Huanglian Jiedu Tang (Coptis Decoction for Resolving Toxicity), Sanhuang Tang (Three Yellows Decoction), Liangge San (Cooling the Chest Powder), and Xiexin Tang (Drain the Heart Decoction) were not used because the ancients favored cold medicines, but rather because their constitutions were robust; thus, using these remedies incurred no risk of damaging the middle jiao with cold, yet achieved the merit of subduing excess fire. Modern individuals possess thinner constitutions, inferior to those of the ancients, and further suffer from depletion due to excessive indulgence. If one employs strongly bitter and cold agents, how could the body withstand them? Moreover, the fire of plague arises from pathogenic factors; once the pathogens are dispersed, the fire naturally subsides. If strongly cold agents are used to directly suppress the fire, there is no capacity to expel pathogens, but rather one first suffers the harm of cold injury. Cold causes stagnation in both the exterior and interior, making it difficult to resolve the pathogens. In summary, strongly bitter and cold herbs such as Huanglian (Coptidis Rhizoma), Huangbai (Phellodendri Cortex), Longdancao (Gentianae Radix), and Kushen (Sophorae Flavescentis Radix) should all be used with caution. The addition or subtraction of herbs like Shengdi Huang (Rehmanniae Radix), Tian Dong (Asparagi Radix), Mai Dong (Ophiopogonis Radix), Yuan Shen (Scrophulariae Radix), Danpi (Moutan Cortex), Zhizi (Gardeniae Fructus), Huangqin (Scutellariae Radix), Yinhua (Lonicerae Flos), Xijiao (Rhinocerotis Cornu), Maogen (Imperatae Rhizoma), Zhuli (Bambusa Textilis Caulis Juice), Tongbian (Infantis Urine), Gegen (Puerariae Lobatae Radix), Shigao (Gypsum Fibrosum), and Renzhonghuang (Human Medicated Soil) is sufficient to clear heat and drain fire with ample margin. If, based on profound insight, the use of Huanglian and similar herbs is deemed indispensable, the dosage should be minimal, measured in fen (0.1 tael) for small amounts or qian (3.73 grams) for larger ones, and must not be excessive.
One might ask: Since strongly bitter and cold agents are contraindicated, why are San Chengqi Tang (Three Draining Qi Decoctions) and Baihu Tang (White Tiger Decoction) used in treating plague? The answer is: Although Shigao (Gypsum Fibrosum) is strongly cold, it contains yang within yin. Its nature is cool yet dispersing; its acridity induces sweating and releases the muscle layer, effectively driving out the vexatious heat caused by warm summerheat, generating fluids, and quenching thirst. Its sweetness moderates the spleen and excels at clearing fire from the lung and triple burner, making it a crucial herb for the Yangming channel. It is suitable for conditions such as manic delirium, yellowish macules, blood rising due to fire pressure, deep-seated heat, and constipation. One should merely choose between raw or calcined forms according to the severity of the disease. Dahuang (Rhei Radix et Rhizoma) is strongly cold and slightly toxic, yet it promotes the elimination of old matter and generation of new, moving freely without staying fixed. For plague symptoms such as manic delirium, yellowish macules, delirious speech, dry impaction, and blood stasis, this herb is indispensable for removal. Fearing its harshness, prepared Dahuang is preferred. As for Mangxiao (Natrii Sulfas), although it is a drastic agent, materia medica praises its efficacy in dispelling epidemic heat, and its ability to soften hardness and break up accumulations cannot be replaced by other herbs. However, compared to Shigao and Dahuang, its use requires greater prudence. Given the evident functions of Dahuang and Shigao, how different are they from those possessing only cold and stagnant properties! This is indeed indispensable for those treating plague.