万病不出乎虚实两端，万方不越乎补泻二法。顾治实之法，犹易知易行，姑置弗论。惟
是治虚
之法，自古难之。世运日衰，元气日薄，虚病日众，方书日繁，而治法日误，何欤？良由误
于因病似虚，因虚致病之分耳，请得论之。所谓因病似虚者，其人本无他恙，或感六淫之邪
，或伤饮食之积，或为情志怫郁，或为气血瘀留，以致精神昏昧，头目昏花，懒于言语，倦
于动作，口中无味，面目痿黄，气短脉沉，厥冷泄泻，种种见证，羸状虽彰，而郁邪内固。
病
者每多不谨于恒，无不以虚自据，而畏攻畏凉，傍人但执外见之形，无不指其虚而劝补。医
者复多不明标本，专听陈言病源，辄投补剂。即有明者，知其因病似虚，而又首鼠两端，恐
遭疑讪，迁延时日，坐失机宜，邪得补而愈甚，积得补而愈深。怫郁者，解散靡从；瘀留者
，滋蔓益甚，又安知此病之所为，非虚之所致也？苟非先去其病，安能即疗其虚。譬之城池
失守，而寇盗得以乘之，乃不事驱攘，惟汲汲于增墉置陴，终当劫资燔舍，斩关排HT 而后
已
。亦何益于事哉？故曰∶因病似虚者，病为本而虚为标，治本而标自己，与其畏虚而酿成不
可起之病，孰若去病而犹冀有可补之虚也，倘有以养正则邪自去，君子进则小人退之说为喻
，是故大虚之中兼有实者论也。若夫因病似虚之不可补，又如一齐众楚，虽进君子之药，转
为小人进之用矣。所谓因虚致病者，其人先天之赋禀素弱，后天之调养复乖。或纵欲而伤精
，或心苦而神耗，或处境有冻馁劳役，或任情有骄姿宴安。精伤者，肾旷其作强之官。神耗
者，心失其君主之用。形寒饮冷伤肺，饥饱劳役伤脾，贫贱者多有之；大怒逆气伤肝，醇醴
浓味伤胃，富贵者多有之。内藏既伤，外患易作，以致阳虚恶寒，阴虚恶热，上气喘满，胁
胀腹膨，前后不通，躁扰闷乱，饮食不入，脉大无根，种种形证，虚而类实。虽肌肉未脱，
而神宰消亡，即起居如常，而患端萌伏。然变证百出，本乎一虚，于此应补之际，而病患旁
人转生疑虑，或谓外邪未散，或谓内积未除。欲补阴，畏寒凉之伤脾；欲补阳，畏燥热之助
火，加之以无断之医，迁就苟合幸试图功。殊不知此病之所为，皆虚之所致也！苟不专治
其
虚，安能分治其实。譬之旱涝相仍，四民失业，盗贼因而蜂起，使非眚灾施赦，发粟赈贫，
而犹以征朱为事，恐朱之则不可胜朱，盗贼未靖而元气益受困矣。故曰∶因虚致病者，虚为
本而病为标，亦治本而标自己，与其去病而虚不可保，毋宁补虚而病可渐除。倘医者徒知应
补，而又不别夫营卫阴阳逆从反正，阳虚而补阴，则如水益深；阴虚而补阳，则如火益热，
犹之因病似虚之法，而治因虚致病之讹也。辨此二者，则虚证治之斯易，又何有方书日众，
治法日误之虑哉！
万种疾病都不外乎“虚”和“实”两个方面，万种方药也不超出“补”和“泻”两种治法。然而，治疗实证的方法，人们还容易知晓和施行，姑且不论。唯独治疗虚证的方法，自古以来就让人感到困难。世道日益衰微，人的元气日益薄弱，虚证患者日益增多，医书日益繁多，但治疗方法却日益错误，为什么呢？确实是由于混淆了“因病致虚（表现为类似虚证）”与“因虚致病（由虚弱导致病症）”的区别罢了，请让我对此加以论述。
所谓“因病似虚”，是指这个人原本没有其他的疾病，或者感受了风、寒、暑、湿、燥、火六淫邪气，或者饮食积滞损伤身体，或者情志抑郁不畅，或者气血瘀滞停留，从而导致精神昏沉模糊，头目眩晕眼花，懒得说话，疲倦于动作，口中无味，面色萎黄，气短脉象沉伏，四肢厥冷腹泻，各种症状表现，虽然呈现出羸弱衰败的表象，但实际上是郁结的邪气在体内固结。病人往往不能谨守常度，无不认为自己是虚证，因而畏惧攻伐疗法和寒凉药物；旁观者只执着于外在可见的形体表现，无不指出这是虚证并劝其进补。医生又多不明辨标本关系，专门听从陈旧的病源说法，轻易投用补剂。即使有明理的医生，知道这是因病而表现出类似虚证的症状，却又犹豫不决，担心遭到怀疑和非议，拖延时日，坐失治疗良机，使得邪气得到补益后更加严重，积滞得到补益后更加深重。对于情志郁结者，无法从解散入手；对于气血瘀留者，滋腻补益反而使病情蔓延更甚。又怎么知道这种病并非由虚所致呢？如果不先去除病因，怎么能立即治疗虚损？这就好比城池失守，盗贼得以趁机入侵，此时不致力于驱逐盗匪，却急切地忙于增高城墙、设置防御工事，最终必然会导致资财被劫掠、房屋被焚烧，盗贼冲破关卡后才肯罢休。这对事情又有什么益处呢？所以说：所谓“因病似虚”，病是根本，虚是标象，治疗根本则标象自然消除。与其畏惧虚证而酿成不可挽救的疾病，不如去除病邪，还留有可以进补的余地。如果有以“培养正气则邪气自去，君子得进则小人退”的说法作为比喻，这就是讨论大虚之中兼有实证的情况。至于说“因病似虚”不可进补，又好比齐国人教唱歌，楚国人在旁边干扰，虽然进用君子的药物，反而变成了助长小人的作用。
所谓“因虚致病”，是指这个人先天禀赋素来虚弱，后天调养又违背规律。或者纵欲过度损伤肾精，或者用心劳苦耗伤心神，或者处境寒冷饥饿、劳累役使，或者任性骄奢、安逸享乐。肾精损伤的，肾脏失去了作强之官的功能；心神耗伤的，心脏失去了君主之用的功能。形体受寒、饮用冷水损伤肺脏，饥饱不均、劳累役使损伤脾脏，贫贱之人多有此类情况；大怒导致气机逆乱损伤肝脏，醇酒厚味损伤胃腑，富贵之人多有此类情况。内脏既已受伤，外部病患就容易发作，从而导致阳虚怕冷，阴虚怕热，上气喘促胀满，胁肋胀满腹部膨隆，大小便不通畅，烦躁扰乱闷塞混乱，饮食无法进入，脉象大而无根，各种形证表现，看似实证实则源于虚损。虽然肌肉尚未脱陷，但主宰生命的神气已经消亡，即使起居如常，但患病的苗头已经潜伏。然而变证百出，根源都在于一个“虚”字。在此应当进补的时候，病患及旁人反而产生疑虑，有的说外邪未散，有的说内积未除。想要补阴，又畏惧寒凉药物损伤脾胃；想要补阳，又畏惧燥热药物助长火势，再加上优柔寡断的医生，迁就苟且、勉强凑合，侥幸试图取得功效。殊不知这种病之所以发生，都是由于虚损所致！如果不专门治疗其虚损，怎么能分别处理其实证？这好比旱涝灾害接连不断，百姓失业，盗贼因此蜂拥而起，如果不是通过减免刑罚、发放粮食赈济贫困来安抚民心，却仍然以征收赋税为事务，恐怕赋税征缴不完，盗贼未能平定，而元气更加困乏了。所以说：所谓“因虚致病”，虚损是根本，病症是标象，也是治疗根本则标象自然消除。与其去除病邪而虚损无法保全，不如补益虚损而病邪可以逐渐消除。如果医生只知道应当进补，却不辨别营卫、阴阳的顺逆正反之理，阳虚却补阴，就像水越加越深；阴虚却补阳，就像火越加越热，这就像是把治疗“因病似虚”的方法，错误地用于治疗“因虚致病”，这是谬误啊。辨明这两种情况，那么虚证的治疗就容易了，又哪里会有医书日益增多、治疗方法日益错误的忧虑呢！
All diseases fall into two categories: deficiency (Xu, 虚) and excess (Shi, 实). All prescriptions do not exceed two methods: tonification (Bu, 补) and purgation (Xie, 泻). However, the method of treating excess is relatively easy to understand and practice, so let us set it aside for now. It is only the method of treating deficiency that has been difficult since ancient times. As the world declines day by day, the primordial Qi (Yuanqi, 元气) becomes thinner day by day, deficiency diseases become more numerous, medical books become more abundant, yet treatment methods become more erroneous. Why? This is indeed due to the confusion between "disease manifesting as deficiency" (Bing Yin Si Xu, 因病似虚) and "deficiency causing disease" (Yin Xu Zhi Bing, 因虚致病). Let me discuss this.
What is meant by "disease manifesting as deficiency"? It refers to a person who originally had no other ailments, but either contracted the six excess pathogens (Liu Yin, 六淫), or suffered from dietary accumulation, or experienced emotional depression, or had Qi and blood stasis retention. This leads to mental confusion, dizziness and blurred vision, reluctance to speak, fatigue in movement, loss of taste in the mouth, sallow complexion, shortness of breath with a deep pulse, cold extremities, and diarrhea. Although various symptoms present a debilitated appearance, the pathogenic factors are internally constrained. Patients often fail to adhere to proper conduct and invariably consider themselves deficient, fearing attack therapies and cooling agents. Bystanders, relying solely on external appearances, invariably point out the deficiency and advise tonification. Doctors, failing to distinguish root and branch, often rely on old explanations of disease origin and readily administer tonifying formulas. Even those who are enlightened, knowing that the disease manifests as deficiency, may hesitate, fearing suspicion and ridicule, delaying time, and missing the optimal opportunity. Consequently, the pathogen becomes worse with tonification, and the accumulation becomes deeper. For emotional depression, there is no way to disperse it; for Qi and blood stasis, nourishing tonification makes it spread further. How can one know that this disease is not caused by deficiency? If the disease is not first removed, how can the deficiency be immediately treated? It is like a city wall falling into disrepair, allowing bandits to take advantage. Instead of driving them away, one busily builds higher walls and parapets. Ultimately, resources will be looted and houses burned, and the bandits will not stop until they break through the gates. What good does this do? Therefore, it is said: In "disease manifesting as deficiency," the disease is the root, and the deficiency is the branch. Treating the root resolves the branch. Rather than fearing deficiency and酿成 (brewing) an incurable disease, it is better to remove the disease and still have room for tonification later. If one uses the analogy of "nourishing righteousness causes evil to depart, and when gentlemen advance, petty men retreat," this discusses the scenario where significant deficiency coexists with excess. Regarding the inadvisability of tonifying "disease manifesting as deficiency," it is like teaching someone to sing in Qi while people from Chu interfere nearby; even if one administers the medicine of a gentleman, it turns into aiding the petty man.
What is meant by "deficiency causing disease"? It refers to a person whose innate constitution was always weak, and whose postnatal care was improper. Whether indulging in desires damages essence, or mental toil consumes spirit, or enduring cold, hunger, and labor, or acting on pride and enjoying luxury. Damage to essence affects the Kidney, which loses its function as the official of strength. Consumption of spirit affects the Heart, which loses its role as the sovereign. Cold form and cold drinks damage the Lung; irregular eating and labor damage the Spleen; these are common among the poor and lowly. Great anger causes Qi rebellion, damaging the Liver; rich wine and heavy flavors damage the Stomach; these are common among the wealthy. Once internal organs are damaged, external afflictions easily arise, leading to Yang deficiency with aversion to cold, Yin deficiency with aversion to heat, upper body asthma and fullness, distension of hypochondrium and abdomen, blockage of front and back (urination and defecation), restlessness and confusion, inability to eat, and a large pulse without root. Various signs and symptoms appear excess-like but originate from deficiency. Although muscles have not wasted away, the governing spirit is fading; even if daily activities are normal, the seeds of illness are latent. Yet, myriad complications arise, all rooted in one deficiency. At this moment when tonification should occur, patients and bystanders generate doubts, claiming external pathogens are not dispersed or internal accumulations are not cleared. Wanting to tonify Yin, they fear cold and cool herbs will damage the Spleen; wanting to tonify Yang, they fear dry and hot herbs will aid fire. Coupled with indecisive doctors who compromise and hope for accidental success, they fail to realize that this disease is entirely caused by deficiency! If one does not specifically treat the deficiency, how can one separately address the excess? It is like successive droughts and floods causing unemployment among the four occupations, leading to banditry. Unless one grants pardons during disasters and distributes grain to relieve poverty, but instead focuses on collecting taxes, the tax collection will never end, the bandits will not be pacified, and the primordial Qi will be further exhausted. Therefore, it is said: In "deficiency causing disease," deficiency is the root, and the disease is the branch. Treating the root resolves the branch. Rather than removing the disease and losing the ability to preserve deficiency, it is better to tonify deficiency so the disease can gradually be eliminated. If a doctor only knows that tonification is needed but fails to distinguish the reversal and correctness of Ying and Wei (Nutritive and Defensive Qi), Yin and Yang, then tonifying Yin for Yang deficiency is like adding water to depth; tonifying Yang for Yin deficiency is like adding fire to heat. This is applying the method for "disease manifesting as deficiency" erroneously to "deficiency causing disease." By distinguishing these two, treating deficiency becomes easy, and what worry is there about increasing medical books and erroneous treatments?