一药有一药之性情功效，其药能治某病，古方中用之以治某病，此显而易见者。然一药
不止
一方用之，他方用之亦效，何也？盖药之功用，不止一端。在北方，则取其此长；在彼方，
则取其彼长。真知其功效之实，自能曲中病情，而得其力。迨至后世，一药所治之病愈多而
亦效者，盖古人尚未尽知之，后人屡试而后知，所以历代本草所注药性，较之《神农本经》
所注功用增益数倍，盖以此也。但其中有当有不当，不若《神农本草》字字精切耳。又同一
热药，而附子之热，与干姜之热，迥乎不同；同一寒药，而石膏之寒，与黄连之寒，迥乎不
同。一或误用，祸害立至。盖古人用药之法，并不专取其寒热温凉补泻之性也。或取其气，
或取其味，或取其色，或取其形，或取其所生之方，或取嗜好之偏，其药似与病情之寒热温
凉补泻若不相关，而投之反有神效。古方中如此者，不可枚举。学人必将《神农本草》字字
求其精义之所在，而参以仲景诸方，则圣人之精理自能洞晓。而已之立方，亦必有奇思妙想
，深入病机，而天下无难治之症也。
世有奸医，利人之财，取效于一时，罔顾人之生死者，谓之劫剂。劫剂者，以重药夺截
邪气
也。夫邪之中人，不能使之一时即出，必渐消渐托而后尽焉。今欲一日见效，势必用猫厣之
药，与邪相争；或用峻补之药，遏抑邪气。药猛 厉，则邪气暂伏，而正亦伤；药峻补，则
正气骤发，而邪内陷。一时似乎有效，及至药力尽，而邪复来，元气已大坏矣。如病者身热
甚，不散其热，而以沉寒之药遏之。腹痛甚，不求其因，而以香燥御之。泻痢甚，不去其积
，而以收敛之药塞之之类，此峻厉之法也。若邪盛而投以大剂参附，一时阳气大旺，病气必
潜藏，自然神气略定，越一二日，元气与邪气相并，反助邪而肆其毒，为祸尤烈，此峻补之
法也。此等害人之术，奸医以此欺人而骗财者十之五。庸医不知，而效尤以害人者，亦十之
五。为医者可不自省，病家亦不可不察也。
每一味药都有其特定的性味和功效，它能治疗某种疾病，古代方剂中用它来治疗该病，这是显而易见的。然而，一味药并不只在一个方剂中使用，在其他方剂中使用也有效，为什么呢？因为药物的功用不止一个方面。在这个方剂中，是取其这一方面的长处；在那个方剂中，则是取其那一方面的长处。真正了解其功效的实质，自然能曲折地契合病情，从而发挥其作用。到了后世，一味药所治疗的疾病越来越多且都有效，这是因为古人尚未完全知晓，后人经过多次尝试后才明白，所以历代本草著作中记载的药性，比《神农本草经》中记载的功用增加了数倍，大概就是这个原因。但是其中有的恰当，有的不恰当，不如《神农本草经》字字精准切要。同样是热性药，附子的热性与干姜的热性，截然不同；同样是寒性药，石膏的寒性与黄连的寒性，也截然不同。一旦误用，祸害立刻到来。因为古人用药的方法，并不专门取用其寒、热、温、凉、补、泻的性质。有时取其气，有时取其味，有时取其色，有时取其形，有时取其所生长的方位，有时取其嗜好的偏性，这些药物似乎与病情的寒热温凉补泻不相关，但投用后反而有神奇疗效。古方中像这样的情况，不可胜数。学习的人必须对《神农本草经》中的每一个字探求其精义所在，并参考张仲景的各种方剂，那么圣人的精妙医理自然能透彻理解。而自己制定的方剂，也必须有奇思妙想，深入探究病机，那么天下就没有难治的疾病了。
世间有奸诈的医生，贪图病人的钱财，只求一时见效，不顾病人生死，这种方剂称为“劫剂”。劫剂，是用猛烈的药物强行截断邪气。邪气侵入人体，不能使其在一时间内立即排出，必须逐渐消除、托出才能彻底清除。现在想要一天就见效，势必使用类似猫厣（一种猛烈药物）的药物，与邪气相争；或者使用峻猛的补药，遏制抑制邪气。如果药物猛烈厉害，则邪气暂时潜伏，但正气也受损；如果药物峻猛大补，则正气突然激发，而邪气内陷。一时之间似乎有效，等到药力耗尽，邪气又回来，元气已经严重败坏了。比如病人身体发热很厉害，不散发其热，而是用沉寒性质的药物遏制它。腹痛很厉害，不探究其原因，而是用香燥性质的药物抵御它。腹泻痢疾很厉害，不去除积滞，而是用收敛性质的药物堵塞它。这类方法属于峻厉之法。如果邪气盛而投以大剂量的人参、附子，一时阳气大旺，病气必然潜藏，自然神气略微安定，过一两天，元气与邪气合并，反而助长邪气肆意肆虐，造成的祸害更加猛烈，这属于峻补之法。这种害人的手段，奸医用来欺骗病人骗取钱财的占十分之五。庸医不懂其中道理，却效仿这种行为害人，也占十分之五。作为医生，怎能不自我反省？病人家属也不可不明察啊。
Each herb possesses its own specific nature, flavor, and efficacy. That a certain herb can treat a specific disease, and that ancient formulas utilize it for that purpose, is self-evident. However, one herb is not used in only one formula; it is also effective when used in other formulas. Why is this? It is because the functions of an herb are not limited to a single aspect. In one formula, its strength in one area is utilized; in another formula, its strength in a different area is utilized. If one truly understands the actual efficacy of an herb, one can naturally align with the patient's condition and harness its power. By later generations, the number of diseases treated by a single herb has increased significantly, yet it remains effective. This is because the ancients had not fully comprehended these aspects, and later practitioners learned through repeated trials. Consequently, the herbal properties recorded in materia medica throughout history have multiplied several times compared to those noted in *Shennong Bencao Jing* (Divine Farmer's Materia Medica). This is precisely why. Nevertheless, among these additions, some are appropriate while others are not; they do not match the precision and relevance of every word in *Shennong Bencao Jing*. Similarly, although both *Fuzi* (Aconiti Lateralis Radix Praeparata) and *Ganjiang* (Zingiberis Rhizoma) are hot-natured herbs, the heat of *Fuzi* differs fundamentally from that of *Ganjiang*; likewise, although both *Shigao* (Gypsum Fibrosum) and *Huanglian* (Coptidis Rhizoma) are cold-natured herbs, their coldness is distinctly different. A single misapplication leads to immediate disaster. This is because the ancients' method of using herbs did not rely solely on their cold, hot, warm, cool, tonifying, or purging natures. Sometimes they utilized the herb's qi, sometimes its flavor, sometimes its color, sometimes its shape, sometimes the direction of its growth, or sometimes its specific preference. These herbs might seem unrelated to the cold, hot, warm, cool, tonifying, or purging nature of the disease, yet upon administration, they often yield miraculous effects. Such instances in ancient formulas are too numerous to enumerate. Practitioners must seek the profound meaning in every word of *Shennong Bencao Jing* and cross-reference it with the various formulas of Zhang Zhongjing. Only then will the sage's refined principles become clear. Furthermore, when formulating prescriptions oneself, one must employ ingenious ideas and deeply penetrate the pathogenesis, thereby ensuring that no disease in the world is incurable.
There exist deceitful physicians in the world who covet patients' wealth, seeking immediate results while disregarding life and death. Such prescriptions are termed "Jie Ji" (Plundering Formulas). A "Jie Ji" employs heavy and drastic drugs to forcibly intercept pathogenic factors. When pathogenic factors invade the human body, they cannot be expelled instantly; they must be gradually eliminated and expelled outward to be completely eradicated. Now, if one desires immediate results within a day, one inevitably resorts to using drastic drugs like *Mao Yan* (a potent herb), engaging in direct conflict with the pathogens; or one uses drastic tonifying drugs to suppress and inhibit the pathogens. If the drugs are fierce and harsh, the pathogens may temporarily subside, but the healthy qi (Zheng Qi) is also damaged; if the drugs are drastically tonifying, the healthy qi suddenly surges, causing the pathogens to sink inward. For a short time, it may seem effective, but once the drug's force dissipates, the pathogens return, and the primordial qi (Yuan Qi) is severely compromised. For example, if a patient suffers from severe fever, instead of dispersing the heat, one uses heavily cold-natured drugs to suppress it. If there is severe abdominal pain, without investigating the cause, one uses aromatic and drying drugs to counteract it. If diarrhea and dysentery are severe, without eliminating stagnation, one uses astringent drugs to block it. These belong to the category of drastic and harsh methods. If pathogens are abundant and one administers large doses of *Renshen* (Ginseng Radix et Rhizoma) and *Fuzi*, causing a sudden surge of yang qi, the disease manifestations may temporarily recede, and the spirit may briefly settle. However, after one or two days, the healthy qi merges with the pathogens, inadvertently assisting them and allowing them to wreak havoc more fiercely. This belongs to the category of drastic tonification. Such harmful techniques are used by deceitful physicians to deceive patients and extort money in five out of ten cases. Ignorant physicians, unaware of the truth, imitate this behavior and harm others, accounting for the other five out of ten cases. Physicians must reflect upon themselves, and patients' families must exercise due diligence.