经言邪气盛则实，精气夺则虚，二句为治病之大关。其词甚显，其义甚微，敢为详辨。
盖实
言邪气实，宜泻也；虚言正气虚，宜补也。凡邪正相搏而为病，则邪实正虚，皆可言也。故
主泻者，则曰邪气盛则实，当泻也；主补者，则曰精气夺则虚，当补也。各执一词，毫无确
据，借口文饰，孰得言非，是以至精之训，反酿莫大之害。不知理之所在，必有不可移易者
，奈医者不能察耳。余请析之为四，孰缓孰急，其有其无也。无虚者，急在邪气，去之不远
，留则生变也；多虚者，急在正气，培之不早，临期无济也；微虚微实者，亦治其实，可一
扫而除也；甚虚甚实者，所畏在虚，但固守根本。以先为己之不可胜，则邪无不退矣。二虚
一
实者，兼其实，开其一面也。二实一虚者，兼其虚，防生不测也。总之，实而误补，固必增
邪，犹或可救；虚而误攻，真气忽去，势必难回，此虚实之缓急，不可不思也。所谓有无者
，察邪气之有无也，凡风寒暑湿燥火，皆能增邪，邪之在表在里在脏在腑，必有所居，求得
其本而直取之。此所谓有，有则邪气之实也，若非六气之邪而病出之阴，则皆情欲以伤内，
劳倦以伤外，似邪非邪，似实非实。此所谓无，无则病在元气也。不明虚实有无之人，必致
以逆为从，以标为本，绝人长命，可不慎哉！
医经中说“邪气盛则实，精气夺则虚”，这两句话是治疗疾病的关键所在。它的字面意思很显浅，但其中的含义却非常深微，我斗胆对此进行详细的辨析。
所谓“实”，是指邪气亢盛，应当采用泻法；所谓“虚”，是指正气虚弱，应当采用补法。凡是邪气与正气相互搏结而致病的情况，都是邪气实、正气虚，这两种情况都可以讨论。所以，主张用泻法的人，就说“邪气盛则实”，认为应当泻；主张用补法的人，就说“精气夺则虚”，认为应当补。双方各执一词，毫无确凿的依据，只是借经文来文饰自己的观点，谁也不能说对方全非，这使得原本极其精辟的教诲，反而酿成了巨大的危害。不知道道理所在之处，必然有不可改变的原则，无奈医生们不能洞察罢了。我请求将这个问题分析为四个方面：孰缓孰急，以及其“有”其“无”。
没有虚证（纯实证）的情况，紧急之处在于邪气，去除它不要迟缓，若滞留不去就会产生变证；多虚证的情况，紧急之处在于正气，培育它如果不早，等到病势危急时就无法挽救了；轻微虚证和轻微实证并存的情况，也可以治疗其实证部分，可以一举扫除清除；极度虚证和极度实证并存的情况，所畏惧的是虚证，只应固守根本。先让自己处于不可被战胜的地位，那么邪气就没有不退去的了。两虚一实的情况，兼顾其实证，打开一条出路；两实一虚的情况，兼顾其虚证，防止发生不测之变。总之，实证误用补法，固然会助长邪气，或许还可以救治；虚证误用攻伐，真气忽然离去，势必难以挽回，这就是虚实缓急的道理，不可不深思啊。
所谓的“有无”，是考察邪气的有无。大凡风、寒、暑、湿、燥、火六淫邪气，都能增加邪气，邪气在表、在里、在脏、在腑，必定有所居留，求得它的本源而直接攻取它。这就是所谓的“有”，“有”就是邪气的实证。如果不是六气之邪，而是病出于阴分，那就是因情志欲望损伤内脏，因劳累倦怠损伤体表，似邪非邪，似实非实。这就是所谓的“无”，“无”就是病在元气上。不明白虚实有无的人，必然会导致把逆治当作顺治，把标症当作本症，断送人的寿命，这能不谨慎吗！
The medical classics state, "When pathogenic factors are exuberant, it is excess; when essential qi is depleted, it is deficiency." These two sentences constitute the critical juncture in treating diseases. Their wording is quite explicit, yet their meaning is profound. I dare to analyze them in detail.
"Excess" refers to the exuberance of pathogenic factors, for which purgation (Xie) should be employed; "deficiency" refers to the weakness of upright qi (Zhengqi), for which tonification (Bu) should be employed. In any disease caused by the struggle between pathogenic factors and upright qi, there is always an excess of pathogens and a deficiency of upright qi, so both aspects can be discussed. Therefore, those who advocate purgation say, "When pathogenic factors are exuberant, it is excess," implying that purgation is indicated; those who advocate tonification say, "When essential qi is depleted, it is deficiency," implying that tonification is indicated. Both sides stick to one view without solid evidence, using textual citations to justify themselves, making it difficult to declare either completely wrong. Consequently, this extremely refined teaching has instead brewed immense harm. The principle at stake must have immutable truths, but unfortunately, physicians fail to perceive them. I propose to analyze this into four categories: which is urgent and which is slow, and whether the condition is "present" or "absent."
In cases with no deficiency (pure excess), the urgency lies in the pathogenic factors; they should be eliminated promptly, as retention will lead to complications. In cases with significant deficiency, the urgency lies in the upright qi; if nourishment is not started early, it will be too late to help when the crisis arrives. When slight deficiency and slight excess coexist, one may treat the excess aspect, clearing it away in one sweep. When severe deficiency and severe excess coexist, what is feared is the deficiency; one should only consolidate the root. By first ensuring one's own invincibility, the pathogenic factors will inevitably recede. In cases of two deficiencies and one excess, one should address the excess while opening a pathway; in cases of two excesses and one deficiency, one should address the deficiency to prevent unpredictable changes. In summary, mistakenly tonifying an excess condition will certainly aggravate the pathogen, though it might still be salvageable; mistakenly purging a deficiency condition causes sudden loss of true qi, which is likely irreversible. Thus, the urgency of excess and deficiency must be carefully considered.
The concept of "presence and absence" refers to examining the presence or absence of pathogenic factors. Wind, cold, summer-heat, dampness, dryness, and fire (Liu Yin, Six Exogenous Pathogens) all contribute to pathogenic accumulation. Whether the pathogen resides in the exterior, interior, zang organs, or fu organs, it must have a specific location; one must identify its origin and attack it directly. This is referred to as "presence," indicating the reality of pathogenic excess. If the disease does not arise from the six climatic pathogens but stems from yin-level disturbances, it is due to emotional desires damaging the interior or fatigue and overwork damaging the exterior. Such conditions resemble pathogens but are not true pathogens, resembling excess but not true excess. This is referred to as "absence," indicating that the pathology lies in the Yuan Qi (Primordial Qi). Physicians who do not understand the distinctions of excess, deficiency, presence, and absence will inevitably mistake counter-indications for indications and symptoms for root causes, thereby shortening lives. Can one not be cautious?