自南阳制方而始，厥后唐、宋、元、明，及国朝以来，成方不可胜纪，焉能熟悉于胸。尝见有读《
千金方》者，有读《医方考》者，有读景岳《新方》者，有读 庵《集解》者，往往宗此而不知彼，宗彼
而不知此者，不待言矣。窃谓古人成方，犹刻文也，临证犹临场也，即有如题之刻文，慎无直抄，必须师其大
意，移步换形，庶几中式。而临证即有对病之成方，亦当谅体之虚实，病之新久而损益之。思成方不在多而
在损益，譬如二陈汤，即夏、苓、陈、草也，治一切痰饮之病，除去陈皮，乃海藏消暑丸，伏暑烦渴用之，
此一减而主治之法，相去迳庭矣。平胃散，即陈、苍、朴、草也，治一切湿气之病，加入芒硝，乃女科之下胎
方，死胎不下用之，此一加而主治之法，相悬霄壤矣。此损益之法也，医者知是理乎？又如气虚用四君，血
虚用四物，倘气血两虚之候者，二方合用名八珍汤，此深一层之病，而加深一层之方也。利湿用五苓，清热
用三石，倘湿热并盛之候者，二方合用名甘露饮，此亦深一层之病，而加深一层之方也。又如固
本丸，治虚劳损证，减去麦冬、生地，名曰三才，以治三焦亏证，此轻一等之病，而减为佐之药也。香苏饮，
治四时感冒，减去香附、紫苏，名曰二贤，以治膈中痰饮，此亦轻一等之病，而减为君之药也。诸如此类，
不可枚举，在医者，必须临证权衡，当损则损，当益则益，不可拘于某病用某方，某方治某病，得能随
机应变，则沉 未有不起也。
自从张仲景（南阳）创制方剂开始，此后经过唐、宋、元、明各代，以及本朝（清朝）以来，现成的方剂多得数不胜数，怎么可能全部熟记于心呢？我曾见过有人只读《千金方》，有人只读《医方考》，有人只读张景岳的《新方》，有人只读吴谦《医宗金鉴》的《集解》，往往尊崇这一派却不知道另一派，尊崇那一派却不知道这一派，这就不必多说了。
我认为古人的成方，就像科举考试中的八股文一样；临证治病，就像参加科举考场一样。即使题目完全相同，也千万不要直接照抄原文，必须领会其大意，灵活变通，这样才能考中（治愈疾病）。而在临床面对具体的病症时，即便有对症的现成方剂，也应当根据患者体质的虚实、病程的新久来进行加减损益。
思考的重点在于：成方的妙处不在于数量多，而在于懂得如何加减损益。例如二陈汤，由半夏、茯苓、陈皮、甘草组成，用于治疗各种痰饮病；如果去掉陈皮，就变成了海藏消暑丸，用于伏暑引起的烦渴，这是一种减法，而主治方向却截然不同了。平胃散，由陈皮、苍术、厚朴、甘草组成，用于治疗各种湿邪致病；如果加入芒硝，就变成了妇科的下胎方，用于死胎不下，这是一种加法，而主治方向却相差天壤之别了。这就是加减损益的方法，医生们明白这个道理吗？
再比如，气虚用四君子汤，血虚用四物汤；如果是气血两虚的情况，将这两个方子合用，名叫八珍汤，这是病情更深一层，所以方剂也加深一层。利湿用五苓散，清热用三石汤（注：此处指代清热利湿类方剂组合或特定三方组合，依原文直译），如果是湿热并重的情况，将这两个方子合用，名叫甘露饮，这也是病情更深一层，所以方剂也加深一层。
又如固本丸，用于治疗虚劳损证；减去麦冬、生地，名叫三才封髓丹（简称三才），用于治疗三焦亏虚之证，这是病情轻一等，所以减少为佐使之药。香苏饮，用于治疗四季感冒；减去香附、紫苏，名叫二贤散，用于治疗膈中痰饮，这也是病情轻一等，所以减少为君药（主药）。诸如此类，不可枚举。作为医生，必须根据临床实际情况权衡利弊，该减则减，该加则加，不能拘泥于“某病用某方，某方治某病”，能够随机应变，那么即使是顽固难治的疾病也没有治不好的。
Since Zhang Zhongjing (of Nanyang) first formulated prescriptions, through the Tang, Song, Yuan, and Ming dynasties, up to the current dynasty (Qing), there are countless established formulas. How could one possibly memorize them all? I have often seen practitioners who only study *Qianjin Fang* (Prescriptions Worth a Thousand Gold), or only study *Yi Fang Kao* (Study of Medical Formulas), or only study Zhang Jingyue’s *Xin Fang* (New Formulas), or only study Wu Qian’s *Jie Jie* (Annotations in the Golden Mirror of Medicine). They often adhere to one school while ignoring another, adhering to one source while ignorant of others; this need not be elaborated upon.
I believe that ancient established formulas are like model essays for the imperial examinations; clinical practice is like taking the examination. Even if the topic is identical, one must never copy verbatim. One must grasp the general principle, adapt flexibly, and thus achieve success (cure). Similarly, when facing specific diseases in clinical practice, even if there is an established formula for the disease, one must assess the patient’s constitution (deficiency or excess) and the chronicity of the illness to modify the formula by adding or subtracting herbs.
The essence of formulas lies not in their quantity, but in the skill of modification. For example, *Erchen Tang* (Two-Cured Decoction), composed of Banxia (Pinelliae Rhizoma), Fuling (Poria), Chenpi (Citri Reticulatae Pericarpium), and Gancao (Glycyrrhizae Radix et Rhizoma), treats various phlegm-fluid retention disorders. If Chenpi is removed, it becomes *Haizang Xiaoshu Wan* (Sea-Hiding Summer-Heat Resolving Pill), used for summer-heat with vexation and thirst. This subtraction results in a completely different therapeutic focus. *Pingwei San* (Stomach-Pacifying Powder), composed of Chenpi (Citri Reticulatae Pericarpium), Cangzhu (Atractylodis Rhizoma), Houpo (Magnoliae Officinalis Cortex), and Gancao (Glycyrrhizae Radix et Rhizoma), treats dampness pathogens. If Mangxiao (Natrii Sulfas) is added, it becomes a gynecological formula for expelling the fetus, used for retained dead fetus. This addition leads to a therapeutic aim vastly different from the original. These are methods of addition and subtraction. Do physicians understand this principle?
Furthermore, *Sijunzi Tang* (Four-Gentlemen Decoction) is used for Qi deficiency, and *Siwu Tang* (Four-Agent Decoction) is used for Blood deficiency. In cases of simultaneous Qi and Blood deficiency, combining these two formulas creates *Bazhen Tang* (Eight-Treasure Decoction). This addresses a deeper level of pathology with a correspondingly more potent formula. *Wuling San* (Five-Ling Powder) is used to promote diuresis and resolve dampness, and *Sanshi Tang* (Three-Stones Decoction) is used to clear heat. In cases where dampness and heat are both abundant, combining these two creates *Ganlu Yin* (Sweet Dew Drink). This too addresses a deeper level of pathology with a corresponding adjustment.
Again, *Guben Wan* (Root-Solidifying Pill) treats consumptive fatigue syndromes. By removing Maidong (Ophiopogonis Tuber) and Shengdi (Rehmanniae Radix), it becomes *Sancai* (Three Talents [Formula]), used to treat deficiencies of the Triple Burner. This addresses a milder condition, reducing ingredients to auxiliary roles. *Xiangsu Yin* (Fragrant Perilla Drink) treats common colds occurring in any season. By removing Xiangfu (Cyperi Rhizoma) and Zisu (Perillae Folium), it becomes *Erxian San* (Two-Worthy Powder), used to treat phlegm-fluid retention in the chest diaphragm. This also addresses a milder condition, reducing ingredients to primary roles.
There are countless such examples. Physicians must weigh the situation clinically, subtracting when appropriate and adding when necessary. One must not rigidly adhere to "this disease uses this formula, this formula treats this disease." Only by adapting flexibly can even severe and chronic diseases be cured.