《经》曰∶夫约方者，犹约囊也，囊满而弗约则输泄，方成弗约，则神与气弗俱，
故医者识脉，方能识病。病与药对，古人惟用一药治之，气纯而功愈速。今人不识病
源，不辨脉理，用药杂乱，则功用不专，而获效者鲜矣。是以医之用药如用兵焉，料敌
出奇者，将之谋也；破军杀贼者，土之力也；审度病机者，医之智也；攻邪伐病者，
药之能也。非士无以破敌，非药无以攻邪。故良将养士，上医蓄药。然不知士何以养？
不知药何以蓄？夫士犹有情实可考，才略可试，尚曰难知，况乎药石无情，才性莫测，
即非言论之可考，又非拟议之可及，而欲知其的然不谬，非细心穷究，其孰能与？假令
尝试漫投，则下咽不返，死生立判，可不大惧哉。上古之人，病生于六淫者多，发于七
情者寡，故其主治尝以一药治一病，或一药治数病。今时则不然，七情弥浓，五欲弥
深，精气既亏，六淫易入，内外胶固，病情殊古，则须合众药之所长，而又善护其所
短，不但既明寒热补泻之性，贵在熟得损益变化之情，我心之意见，与药之性情，如契
合神交，方能得心应手，其图平定之功，则断无伤生之误矣。尊生者可不潜心细究乎。
五脏苦欲补泻乃用药第一义也，何则？五脏之内，各有其神，神各有性，性复各
殊，故形而上者神也，有知而无质，形而下者块然者也。五脏之体也，有质而无知，各
各分断者也。肝藏魂，肺藏魄，心藏神，脾藏意与智，肾藏精与志，皆指有知之性而
言，即神也。神也者，阴阳不测之谓也。是形而上者，藏之性也。惟其无形，故能主乎
有形。所谓苦欲者，犹言好恶也。违其性故苦，遂其性故欲。欲者，是本脏之神之所好
也，即补也。苦者，是本脏之神之所恶也，即泻也。补泻系乎苦欲，苦欲因乎脏性，不
属五行，未落阴阳，其神用之为与！如肝苦急，急则有摧折之意焉，故苦而恶之，急食
甘以缓之，缓之是使遂其性也。且扶苏条达，木之象也，升发开展，魂之用也，故其
性欲散，急食辛以散之，散之解其束缚也，是散即补也。心苦缓，盖心为君主，神名之
性，喜收敛，而恶散缓，急食酸以收之，收之是使遂其性也。且心君本自和调，若邪热
乘之则躁急，急食咸以软之，软者，和调之义，除其邪热，以软其躁急坚劲之气，使复
其平，下交于肾，得既济之道，故软即补也。脾苦湿，宜健而不宜滞，若湿乃滞矣，
急食苦以躁之，使复其性之所喜，脾斯健矣。若已过躁，则复欲缓之，稼穑之化甘先
入脾，故急食甘以缓之，以甘补之。肺为气主，常则气顺，变则气逆，逆则违其性也，
故宜急食苦以泄之。且肺主上焦，其政敛肃，故其性喜收，宜急食酸以收之。更贼肺
者，热也，肺受热邪，急食辛以泻之，不敛则气无所管束，是肺失其职也。故宜收之以
酸，使遂其收敛之性，以清肃于上，收之是即补也。肾苦燥，盖肾藏精与志，而主五
液，乃属真阴水脏，其性本润，而恶涸燥，故宜急食辛以润之。且肾欲坚，盖肾非坚，
则无以称作强之职，但四气以遇湿热即软，遇寒冷即坚；五味以得咸即软，得苦即坚，
故宜急食苦以坚之，以遂其欲坚之性也，是坚即补也。苦欲即明，而五味更当详审。水
曰润下，润下作咸；火曰炎上，炎上作苦；木曰曲直，曲直作酸；金曰从革，从革作
辛；土爰稼穑，稼穑作甘。苦者直行而泄，辛者横行而散，酸者束而收敛，咸者止而软
坚，甘之一味可上可下，土位居中，而兼五行也，淡之一味，五脏无归，专入太阳而利
小便也。然草木有形无情之药，各逞一性以为功。人禀五行有神有情之体，全以阴阳变
化制伏，相成相长以为之用。倘失调抱 ，驱药救弊，徒知以寒治热，则热病转生，以
热治寒，而寒病转剧，惟宜求其本以衰之，因所因以伏之。即《经》所谓∶“必先其所
主，而伏其所因”，斯无增气偏胜之害，而得和平长养之宜，令无情以至有情，皆出用
药者神明变化之用，学人可不潜心默会其旨乎！昔贤祝医者曰∶“行欲方而智欲圆，心
欲小而胆欲大”。嗟呼！医之神良尽乎此矣。
《黄帝内经》说：约束方剂，就像扎紧口袋一样。口袋满了如果不扎紧就会漏泄，方剂配成了如果不讲究法度（如君臣佐使的严谨结构），那么神气就不能与药力协同作用。所以医生只有精通脉诊，才能准确识别疾病。病证与药物相对，古人往往只用一味药来治疗，因为药性纯粹，疗效更快。现在的人不认识病源，不辨别脉理，用药杂乱无章，导致功效不专一，因此获得疗效的人很少了。因此，医生用药如同将领用兵：料敌制胜是将军的谋略；破军杀贼是士兵的力量；审察病情机理是医生的智慧；攻邪治病是药物的能力。没有士兵无法破敌，没有药物无法攻邪。所以优秀的将领善于培养士兵，高明的医生善于储备和运用药物。然而，不知道如何培养士兵？不知道如何储备药物？士兵尚且有真情实感可以考察，才华谋略可以测试，还说难以了解，何况药物没有情感，药性和才情难以揣测，既不能用言语完全考证，也不能仅凭推测达到，想要知道其确切无误的道理，如果不是细心深入探究，谁能做到呢？假如随意尝试投药，一旦入口就无法挽回，生死立刻判定，这难道不值得恐惧吗？上古时期的人，多因六淫（风、寒、暑、湿、燥、火）致病，少因七情（喜、怒、忧、思、悲、恐、惊）致病，所以主治方法常是一味药治一种病，或一味药治多种病。现在的时代则不然，七情更加浓烈，五欲更加深沉，精气已经亏损，六淫容易侵入，内外邪气胶结固着，病情与古代大不相同，这就必须集合众多药物的长处，又善于保护其短处，不仅要明白寒热补泻的药性，更贵在熟练掌握损益变化的规律，让医者的心意与药物的性情像神灵交合一样默契，才能得心应手，从而达成平定病邪的功效，就一定不会有伤害生命的失误了。珍爱生命的人能不潜心细致探究吗？
五脏的苦欲补泻是用药的第一要义，为什么呢？五脏之内，各有其神，神各有其性，性又各不相同。所以，形而上的层面是“神”，有知觉但没有实体；形而下的层面是“块然”的物质，即五脏的形体，有实体但没有知觉，各自分开独立存在。肝藏魂，肺藏魄，心藏神，脾藏意与智，肾藏精与志，这些都是指有知觉的本性而言，也就是“神”。所谓神，就是阴阳变化不可测度的表现。这是形而上的层面，是脏腑所藏的“性”。正因为无形，所以能主宰有形的躯体。所谓的“苦欲”，就是好恶的意思。违背它的本性就是“苦”，顺应它的本性就是“欲”。所谓“欲”，是本脏之神所喜欢的，也就是“补”；所谓“苦”，是本脏之神所厌恶的，也就是“泻”。补泻取决于苦欲，苦欲源于脏性，不属于五行生克，未落入阴阳范畴，这是神在发挥作用啊！例如：肝苦急，急迫就有摧折之意，所以肝感到痛苦并厌恶它，应当紧急食用甘味药来缓和它，缓和就是顺应它的本性。而且树木舒展条达，是木的形象，升发开展，是魂的作用，所以肝的欲望是发散，应当紧急食用辛味药来发散它，发散解除了束缚，发散即是补。心苦缓，因为心为君主，神明的本性喜欢收敛，而厌恶散漫迟缓，应当紧急食用酸味药来收敛它，收敛就是顺应它的本性。而且心君本来和谐调顺，如果邪热侵袭就会躁急，应当紧急食用咸味药来软化它，软化是和调的意义，去除邪热，以软化其躁急坚劲的气机，使其恢复平和，下交于肾，达到水火既济之道，所以软化即是补。脾苦湿，适宜健运而不宜停滞，如果湿气导致停滞，应当紧急食用苦味药来燥湿，使其恢复本性所喜的状态，脾就健运了。如果过于燥烈，又想缓和它，稼穑之化甘味先入脾，所以应当紧急食用甘味药来缓和它，以甘味补益脾土。肺为气之主，常态下气机顺畅，病变时气机上逆，逆则违背其本性，所以适宜紧急食用苦味药来泄降肺气。而且肺主上焦，其政令主收敛肃降，所以其本性喜欢收敛，适宜紧急食用酸味药来收敛它。再侵害肺的，是热邪，肺受热邪侵袭，应当紧急食用辛味药来泻热，如果不收敛，气就无所管束，这是肺失职守。所以适宜用酸味收敛，以顺应其收敛的本性，使上焦清肃，收敛即是补。肾苦燥，因为肾藏精与志，主五液，属于真阴水脏，其本性本润，而厌恶干枯燥裂，所以适宜紧急食用辛味药来滋润它。而且肾欲坚，因为肾如果不坚固，就无法胜任强壮身体的职责，但四气遇到湿热就软，遇到寒冷就坚；五味得到咸味就软，得到苦味就坚，所以适宜紧急食用苦味药来坚固它，以顺应其欲坚的本性，坚固即是补。苦欲明白了，五味就更应当详细审视。水性润下，润下产生咸味；火性炎上，炎上产生苦味；木性曲直，曲直产生酸味；金性从革，从革产生辛味；土性稼穑，稼穑产生甘味。苦味直行而泄降，辛味横行而发散，酸味束敛而收敛，咸味止涩而软坚，甘味这一种性质可上可下，土位居中央，兼有五行特性；淡味这一种性质，五脏无归属，专门进入太阳经而通利小便。然而草木是有形无情的药物，各自逞显一种药性来立功。人禀受五行，是有神有情之体，全靠阴阳变化制伏，相生相长来发挥作用。如果失调抱病，驱遣药物补救弊端，只知道以寒治热，则热病反而加重；以热治寒，则寒病反而剧烈。只适宜探求根本来削弱病势，顺着病因来制服它。正如《内经》所说：“必先明其所主，而伏其所因”，这样就没有增气偏胜的危害，而得到和平长养的适宜，让无情之物发挥至有情之效，都出自用药者神明变化的妙用，学习者能不潜心默会其中的旨意吗？从前贤人告诫医生说：“行为要方正而有原则，智慧要圆融而无滞碍，心思要缜密谨慎，胆量要宏大果敢。”唉！医生的神妙良善全都体现在这里了。
The *Classic* states: Restraining a prescription is like tying a bag. If the bag is full but not tied, contents will leak; if a prescription is formed but lacks restraint (strict structural rules), the spirit and qi will not act in concert. Therefore, only by mastering pulse diagnosis can a physician accurately identify diseases. When disease corresponds to medicine, ancients often used a single herb to treat, for its pure nature yields faster efficacy. Today's practitioners, failing to recognize disease sources or differentiate pulse patterns, use chaotic medications, resulting in unfocused effects and few successes. Thus, a physician uses medicine like a general uses troops: anticipating enemies and devising strategies is the general's wisdom; breaking armies and killing thieves is the soldier's strength; assessing pathogenesis is the physician's intelligence; attacking evil and curing disease is the herb's capability. Without soldiers, one cannot defeat enemies; without herbs, one cannot attack evil. Hence, good generals nurture soldiers, and superior physicians stockpile and utilize herbs. However, how does one nurture soldiers? How does one stockpile herbs? Soldiers have emotions to examine and talents to test, yet are still said to be hard to know; how much more so are herbs, which lack emotion and whose natures are unpredictable? They cannot be fully verified by words nor reached by mere speculation. To know their exact, error-free principles requires careful and thorough investigation; who else could achieve this? If one attempts random administration, once swallowed, it cannot be retrieved; life and death are decided instantly. Is this not terrifying? In ancient times, people suffered mostly from the Six Excesses (Wind, Cold, Summerheat, Dampness, Dryness, Fire) and rarely from the Seven Emotions (Joy, Anger, Worry, Thought, Sorrow, Fear, Fright). Thus, treatment often involved one herb for one disease, or one herb for multiple diseases. Today is different: emotions are intense, desires are deep, essence and qi are depleted, and the Six Excesses easily invade. Internal and external pathogens adhere firmly, making conditions vastly different from antiquity. One must combine the strengths of many herbs while mitigating their weaknesses. Not only must one understand the properties of Cold, Heat, Tonification, and Drainage, but one must also master the dynamics of benefit and loss. The physician's intent and the herb's nature must merge like spirits interacting, enabling effortless application and achieving pacification without harming life. Those who value life should not study this deeply.
The tonification and drainage based on the Five Zang organs' "Bitter" (Ku) and "Desire" (Yu) are the first principle of medication. Why? Within each Zang organ resides a Spirit (Shen), each with its own Nature (Xing), and these Natures differ. Form above (Xing er shang) refers to the Shen, which has perception but no substance; form below (Xing er xia) refers to the physical mass, i.e., the Zang organs, which have substance but no perception, existing separately. The Liver stores Hun (Ethereal Soul), the Lung stores Po (Corporeal Soul), the Heart stores Shen (Spirit), the Spleen stores Yi (Intellect) and Zhi (Will), and the Kidney stores Jing (Essence) and Zhi (Will/Fear). These refer to the sentient nature, i.e., the Shen. Shen is defined as the unfathomable interplay of Yin and Yang. This is the formless aspect, the stored Nature. Because it is formless, it governs the有形 (physical) body. "Bitter" and "Desire" refer to likes and dislikes. Violating its nature causes "Bitterness" (distress); fulfilling its nature creates "Desire". "Desire" is what the organ's Spirit likes, which constitutes Tonification (Bu). "Bitterness" is what the organ's Spirit dislikes, which constitutes Drainage (Xie). Tonification and Drainage depend on Bitter and Desire; Bitter and Desire stem from Organ Nature, transcending the Five Elements and Yin-Yang categories, acting through the Shen. For example: The Liver suffers from tension (Ji), which implies destruction; thus it is bitter and dislikes it. Urgently consume Sweet (Gan) herbs to relax it; relaxing fulfills its nature. Wood spreads and reaches out, representing the image of Wood; rising and expanding is the function of Hun. Thus, the Liver desires dispersion; urgently consume Acrid (Xin) herbs to disperse it; dispersing releases constraints, and dispersion is Tonification. The Heart suffers from laxity (Huan). As the Monarch, the Spirit's nature prefers convergence and dislikes laxity. Urgently consume Sour (Suan) herbs to astringe it; astringing fulfills its nature. The Heart Monarch is naturally harmonious; if invaded by pathogenic heat, it becomes restless. Urgently consume Salty (Xian) herbs to soften it; softening means harmonizing, removing heat, and softening restless, rigid qi, restoring balance and allowing downward interaction with the Kidney (Water-Fire intersection/Ji Ji). Thus, softening is Tonification. The Spleen suffers from Dampness (Shi); it favors movement over stagnation. Dampness causes stagnation; urgently consume Bitter (Ku) herbs to dry it, restoring its preferred state, thereby strengthening the Spleen. If overly dry, one seeks to moisten/harden; Sweet (Gan) enters the Spleen first due to Earth's transformation; thus, urgently consume Sweet herbs to moderate it, using Sweet to Tonify. The Lung is the master of Qi; normally smooth, when pathological, it rebels. Rebellion violates its nature; thus, urgently consume Bitter herbs to drain rebellious Qi. The Lung governs the Upper Jiao, its policy is收敛 (convergence) and肃降 (descending). Its nature prefers convergence; urgently consume Sour herbs to astringe it. Heat harms the Lung; when invaded by heat, urgently consume Acrid herbs to drain heat. Without convergence, Qi is uncontrolled, indicating Lung dysfunction. Thus, use Sour to converge, fulfilling its convergent nature to clear the Upper Jiao; convergence is Tonification. The Kidney suffers from Dryness (Zao). The Kidney stores Essence and Will, governs fluids, and belongs to True Yin Water. Its nature is moist and dislikes aridity; thus, urgently consume Acrid herbs to moisten it. The Kidney desires firmness (Jian). Without firmness, it cannot strengthen the body. Four Qi become soft in damp-heat and firm in cold; Five Flavors become soft with Saltiness and firm with Bitterness. Thus, urgently consume Bitter herbs to firm it, fulfilling its desire for firmness; firmness is Tonification. Once Bitter/Desire is understood, Five Flavors require detailed examination. Water moistens downward, producing Saltiness; Fire flares upward, producing Bitterness; Wood curves and straightens, producing Sourness; Metal transforms, producing Acridity; Earth plants and harvests, producing Sweetness. Bitter moves straight and drains; Acrid moves horizontally and disperses; Sour binds and converges; Salty stops and softens hardness; Sweet can move up or down, Earth is central and encompasses all Five Elements; Pale (Dan) flavor has no specific Zang affiliation, enters the Taiyang channel, and promotes urination. Herbs are有形 (physical) and devoid of情 (emotion/sentience), each exerting power through a single nature. Humans inherit Five Elements, possessing bodies with Shen and 情, relying entirely on Yin-Yang transformations, mutual restriction and growth for function. If disharmony occurs and drugs are driven to remedy defects, knowing only to use Cold for Heat leads to intensified heat; using Heat for Cold leads to intensified cold. One must seek the root to weaken it and follow the cause to subdue it. As the *Classic* says: "First determine the primary target, then subdue the underlying cause." This avoids the harm of excessive Qi dominance and achieves peaceful nourishment. Transforming the inert into the sentient relies on the physician's divine variation. Students should not fail to silently comprehend this purport! Ancients advised physicians: "Conduct yourself with integrity (Fang) but wisdom with flexibility (Yuan); keep your heart small (cautious) and your courage large." Alas! The divine excellence of medicine lies herein.