前药赋性甘寒。固非苦劣之品。亦只宜于燥热实症者。虽方书有云甘寒不犯胃气。愚以
为不然夫味
之甘者固与脾合。而性之寒者独不与脾忤乎。连泻心肝火。龙胆泻肝胆火。白芍泻脾火。黄
柏知母泻肾
火。石膏泻胃火。葛根泻阳明火。滑石利六腑之涩结。泻膀胱之实火。芩连兼泻大肠火。小
肠佐木通。与心
肾同治。柴胡专主足厥阴少阳。而他经之热不可混用也。四物汤虽曰补血。而丹溪以芍性酸
寒。能伐生发
之气。为产后所忌。东垣又以春夏腹痛用芍。秋冬腹痛用桂皆因非实热不得概投寒剂而又推
之天时
人事则立言独迥时流矣奈何丹溪以黄柏知母为补阴之用。未免遗议千古夫阴虚矣未有诸脏能
独
盛者根本既摇枝叶自萎理必然也切谓人身不过气血两端。故左肾为精血之原。为诸阴之主。
右肾为
脾胃之母。为元阳之根精血耗矣则阴为虚阴既虚矣而阳无附相火随炽。真阴日涸。发为燎
原假热之
症。岂知真阳无附母气既馁子脾何资致失转输之令遂乏生化之机即四脏亦为之虚也故欲滋生
精血。且秉质膏润。善滑大肠。历观诸家本草。盛称其微。独濒湖有云胃虚者禁用。优劣宜
忌。始判然矣。余
见世医治虚痨嗽痰发热诸症。亦有不敢误投黄柏知母。而二冬贝母栝蒌玄参地骨。是所不免
。每每增
剧脾气顿伤转为火脱便泄之症岂知阴虚。则诸脏俱虚幸赖天生一线胃气。尚尔留连岁月。一
投以寒
滑之剂。只速其死耳。若其脉症俱实。真原未斫。肠胃燥热。用之何妨。凡治病须觇元气虚实
。胃气衰旺。切不宜循症投剂。此是医家第一大关键。
前面的药物性质甘寒，确实不是苦劣的药材。但也只适用于燥热实证的患者。虽然医书上有说“甘寒不伤胃气”，但我认为并非如此。味道甘的药物固然与脾相合，但性质寒凉的药物难道就不与脾相抵触吗？黄连泻心火和肝火，龙胆草泻肝胆之火，白芍泻脾火，黄柏和知母泻肾火，石膏泻胃火，葛根泻阳明经之火，滑石通利六腑的涩结，泻膀胱的实火，黄芩和黄连兼泻大肠之火，小肠火借助木通，与心和肾同治。柴胡专门主治足厥阴肝经和少阳胆经的热证，其他经络的热证不可混用。四物汤虽然说是补血方，但朱丹溪认为芍药性味酸寒，能损伤生发之气，是产后所忌用的。李东垣又提出春夏季节腹痛用芍药，秋冬季节腹痛用桂枝，这都是因为如果不是实热证，就不能一概投以寒凉药剂，进而推演天时人事，其立论确实远超当时的一般医生。
然而，朱丹溪将黄柏、知母作为补阴之用，未免留下了千古争议。既然阴虚了，没有哪个脏腑能单独亢盛的，根本既已动摇，枝叶自然枯萎，这是必然的道理。我认为人身不过气血两端。左肾是精血的源头，是诸阴的主宰；右肾是脾胃的母亲，是元阳的根本。精血耗损则阴为虚，阴既已虚，阳气无所依附，相火随之炽盛，真阴日渐枯竭，引发燎原般的假热症状。哪里知道真阳无所依附，母气既已衰弱，子脏（脾）如何能得到资助，从而失去转输的功能，缺乏生化之机，就连其他四脏也会因此虚弱。所以想要滋生精血，且质地膏润，善于滑利大肠。纵观各家本草，大多称赞它的好处，唯独李时珍（濒湖）说胃虚者禁用，优劣禁忌，这才判然分明。
我见世间的医生治疗虚劳咳嗽、痰多、发热等症状，也有不敢误投黄柏、知母的，但对于二冬（天冬、麦冬）、贝母、栝蒌、玄参、地骨皮等药，却往往不免使用。结果每每使病情加重，脾气顿时受伤，转为火脱便泄的症状。哪里知道阴虚则诸脏俱虚，幸好赖有天生的一线胃气，还能勉强维持岁月。一旦投以寒凉滑利的药剂，只会加速死亡罢了。如果脉症都属实证，真元未受砍伐，肠胃燥热，使用这些药又有什么妨碍呢？大凡治病必须观察元气的虚实，胃气的衰旺，切不可以症套药，这是医家的第一大关键。
The aforementioned drugs possess a sweet and cold nature. Indeed, they are not bitter or inferior substances, but they are only suitable for patients with dry-heat excess syndromes (Zao Re Shi Zheng). Although medical texts state that "sweet-cold herbs do not invade the Stomach Qi," I believe this is incorrect. Substances with a sweet taste naturally harmonize with the Spleen, but those with a cold nature—do they not conflict with the Spleen? Huang Lian (Coptis Rhizome) drains Heart and Liver Fire; Long Dan Cao (Gentian Root) drains Liver and Gallbladder Fire; Bai Shao (White Peony Root) drains Spleen Fire; Huang Bo (Phellodendron Bark) and Zhi Mu (Anemarrhena Rhizome) drain Kidney Fire; Shi Gao (Gypsum Fibrosum) drains Stomach Fire; Ge Gen (Pueraria Root) drains Yangming Fire; Hua Shi (Talcum) unblocks the obstruction of the Six Fu organs and drains Bladder Excess Fire; Qin Lian (Huang Qin and Huang Lian) jointly drain Large Intestine Fire; Small Intestine Fire is assisted by Tong Cao (Tetrapanax Medulla), treating the Heart and Kidney simultaneously. Chai Hu (Bupleurum Root) specifically governs the Foot Jueyin (Liver) and Shaoyang (Gallbladder) meridians; heat in other meridians must not be treated indiscriminately with it.
Si Wu Tang (Four Substance Decoction) is said to nourish Blood, but Zhu Danxi argued that Shao Yao (Peony Root), being sour and cold, can impair the vitalizing and ascending Qi, making it contraindicated postpartum. Li Dongyuan further proposed using Shao Yao for abdominal pain in spring and summer, and Gui Zhi (Cinnamon Twig) for abdominal pain in autumn and winter. This reasoning stems from the principle that cold agents should not be administered generally unless there is excess heat, extending this logic to seasonal changes and human activities, thereby establishing theories far superior to those of his contemporaries.
Nevertheless, Zhu Danxi’s use of Huang Bo and Zhi Mu as Yin-nourishing agents has invited criticism throughout history. When Yin is deficient, no single Zang organ can remain hyperactive; once the root is shaken, the branches inevitably wither. This is an inevitable law. I posit that the human body consists essentially of Qi and Blood. The Left Kidney is the source of Essence and Blood and the master of all Yin. The Right Kidney is the mother of the Spleen and Stomach and the root of Primordial Yang. When Essence and Blood are depleted, Yin becomes deficient. Once Yin is deficient, Yang has no anchor, and Ministerial Fire (Xiang Huo) flares up. True Yin dries up daily, leading to symptoms of false heat resembling a prairie fire. How could one know that when True Yang has no anchor and Mother Qi (Kidney) is weakened, the Child Organ (Spleen) cannot receive support, thus losing its transportive function and failing to generate transformation? Consequently, the other four Zang organs also become deficient. Therefore, to generate Essence and Blood, one requires substances that are rich and moistening, and good at lubricating the Large Intestine. Reviewing various Materia Medica, most praise these herbs, but only Li Shizhen (Binhu) stated they are contraindicated for those with Stomach deficiency. Thus, their advantages and contraindications became clear.
I have observed physicians treating consumptive cough, phlegm, and fever. While some dare not mistakenly prescribe Huang Bo and Zhi Mu, they often resort to Er Dong (Tian Dong and Mai Dong), Bei Mu (Fritillaria Bulb), Gua Lou (Trichosanthes Fruit), Xuan Shen (Scrophularia Root), and Di Gu Pi (Lycium Bark). This frequently exacerbates the condition, suddenly injuring Spleen Qi and transforming into symptoms of Fire collapse and diarrhea. They fail to realize that when Yin is deficient, all Zang organs are deficient. Fortunately, a thread of congenital Stomach Qi remains, allowing life to persist for years. However, administering cold and slippery agents will only hasten death. If the pulse and symptoms both indicate excess, and the primordial essence is intact, with dry-heat in the intestines and stomach, what harm is there in using them? In treating any disease, one must inspect the deficiency or excess of Yuan Qi (Primordial Qi) and the decline or vigor of Wei Qi (Stomach Qi). One must strictly avoid prescribing merely based on symptoms. This is the primary key for physicians.