凡伤寒治法，在表者宜散，在里者宜攻，此大则也。然伤寒死生之机，则全在虚实
二字，夫邪之所凑，其气必虚，故伤寒为患，多系乘虚而入者。时医不察虚实，但见伤寒，
则动曰伤寒无补法，任意攻邪。殊不知可攻而愈者，原非虚证，正既不虚，邪自不能害之，及
其经尽气复，自然病退，故治之亦愈，不治亦愈，此实邪之无足卢也。惟是挟虚伤寒，则
最为可畏，使不知固本御侮之策，而肆意攻邪，但施孤注，则凡攻散之剂，未有不先入于
胃，而后达于经，邪气未相及，而胃气先被伤矣，即不尽脱，能无更虚？元气更虚，邪
将更入，虚而再攻，不死何待？是以凡患伤寒而死者，必由元气之先败，此则举世之通弊
也。故凡临证者，但见脉弱无神，耳聋手颤，神倦气怯，畏寒喜暗，言语轻微，颜色青白，
诸形证不足等候，盒饭思顾元气。若形气本虚，而过散其表，必至亡阳；脏气本虚，而误
攻其内，必至亡阴，犯者必死。即如元气半虚，而邪方盛者，亦当权其轻重，而兼补以散，
庶得其宜。若元气大虚，则邪气虽盛，亦不可攻，必当详察阴阳，峻补中气。如平居偶感阴
寒，邪未深入，但见发热身痛，脉数不洪，内无火证，素禀不足者，即当用理阴煎加柴
胡，或加麻黄，连进一二服，其效如神，此常用第一方也。此外诸证，如虚在阳分，则当
以四柴胡饮、补中益气汤，或八珍汤、理中汤、温胃饮之类，此温中自能发散之治也。若虚
在阴分，而液涸水亏，不能作汗，则当用补阴益气煎、三柴胡饮，或三阴煎、左归饮之类，
此壮水制阳，精化为气之治也。若阴盛格阳，真寒假热者，则当以大补元煎、右
归饮、崔氏八味丸料之类，此引火归原之治也。其有阴盛阳衰之证，身虽发热，而畏寒不已
，或呕
恶，或泄泻，或背凉如冰，或手足厥冷，是皆阳虚之极，必用大温中饮，或理阴煎，不可疑也。若
果邪火热甚，而水枯干涸者，或用凉水渐解其热。表未解而固闭者，或兼微解，渐去其寒。若邪实
正虚，原有主客不敌之势，使但能保定根本，不令决裂，则邪将不战而自解。此中大有玄妙，余常
藉此而存活者，五十年来若干人矣，谨书之以为普济者之则。
凡是治疗伤寒的方法，病邪在体表的适宜用发散法，病邪在体内的适宜用攻下法，这是大的原则。然而，伤寒决定生死的关键，完全在于“虚”和“实”这两个字。大凡邪气聚集的地方，人体的正气必定虚弱，所以伤寒为患，多是趁着人体虚弱而侵入的。当时的医生不考察虚实，只要见到伤寒，就动不动说“伤寒没有补益的方法”，任意地攻伐邪气。殊不知那些通过攻下而痊愈的病例，原本就不是虚证，正气不虚，邪气自然不能伤害它，等到病程结束、气血恢复，病自然会退去，所以治疗也能好，不治疗也能好，这其实是邪气不足为惧。只有那种夹杂虚证的伤寒，才是最令人畏惧的，如果不知道固护根本、抵御外侮的策略，而肆意攻伐邪气，只是孤注一掷地使用攻散的药物，那么凡是攻散的药剂，没有不是先进入胃中，然后才到达经络的，邪气还没有波及到那里，胃气先被损伤了，即使没有完全脱失，难道不会更加虚弱吗？元气更加虚弱，邪气将更深入，在虚的基础上再次攻伐，不死还等什么？因此，凡是患伤寒而死的人，必定是因为元气先败坏了，这是举世通用的弊病。所以凡是临证时，只要见到脉象微弱无神，耳聋手颤，精神疲倦气机怯弱，怕冷喜欢昏暗环境，说话声音轻微，面色青白，各种形证都表现出不足的样子，就应该想着顾护元气。如果形体气质本来虚弱，而过分散发其表，必然导致亡阳；脏气本来虚弱，而误攻其内，必然导致亡阴，犯此错误的人必死。就像元气半虚，而邪气正盛的时候，也应当权衡轻重，兼用补益和发散的方法，这样才能得当。如果元气大虚，那么邪气虽然旺盛，也不可以攻伐，必须详细察辨阴阳，峻补中气。比如平时偶尔感受阴寒之邪，邪气尚未深入，只见到发热身痛，脉数但不洪大，体内没有火证，素来体质不足的人，就应当使用理阴煎加柴胡，或者加麻黄，连续服用一两剂，效果如神，这是常用的第一方。此外其他证候，如虚在阳分，就应当用四柴胡饮、补中益气汤，或者八珍汤、理中汤、温胃饮之类，这是通过温中达到自能发散的治疗。如果虚在阴分，而津液枯竭水亏，不能作汗，就应当用补阴益气煎、三柴胡饮，或者三阴煎、左归饮之类，这是壮水制阳，精化为气的治疗。如果阴盛格阳，真寒假热的情况，就应当用大补元煎、右归饮、崔氏八味丸料之类，这是引火归原的治疗。其中有阴盛阳衰的证候，身体虽然发热，但怕冷不止，或者呕吐恶心，或者泄泻，或者背部凉如冰，或者手足厥冷，这些都是阳气虚极的表现，必须用大温中饮，或者理阴煎，不可迟疑。如果确实是邪热火气很盛，而水枯干涸的，可以用凉水逐渐解除其热。表邪未解而正气固闭的，或者兼用微解的方法，逐渐去除其寒。如果邪气实而正气虚，原本就有主客力量不敌的形势，如果能保卫好根本，不让其决裂，那么邪气将不战而自解。这其中大有玄妙，我常借此而救活的人，五十年来有若干人了，谨慎地写下来作为普济世人的准则。
In general, the treatment of Shanghan (Cold Damage) follows the principle that pathogenic factors in the exterior should be dispersed, while those in the interior should be purged. This is a major guideline. However, the critical factor determining life and death in Shanghan lies entirely in the concepts of Deficiency (Xu) and Excess (Shi). Wherever pathogenic factors gather, the body's Qi must be deficient; thus, complications from Shanghan often arise when pathogens take advantage of such deficiency to invade. Contemporary physicians, failing to examine the balance of Deficiency and Excess, merely upon observing Shanghan, frequently assert that "Shanghan has no place for tonification," and arbitrarily employ methods to attack the pathogen. They fail to realize that cases cured by purging were originally not Deficient patterns; since the Righteous Qi was not deficient, the Pathogenic Factor could not harm it. When the disease course concludes and Qi recovers, the illness naturally subsides. Therefore, whether treated or not, recovery occurs; this demonstrates that the Pathogenic Factor itself is not formidable. It is only in cases of Shanghan complicated by Deficiency that one should be most apprehensive. If one does not adopt strategies to consolidate the Root and resist invasion, but instead recklessly attacks the pathogen with solitary measures, any dispersing or purgative agents will first enter the Stomach before reaching the meridians. Before the pathogen can affect the target, the Stomach Qi will already be damaged. Even if total collapse does not occur, will there not be further deficiency? As Yuan Qi becomes more deficient, the pathogen will penetrate deeper. Attacking again in a state of deficiency—what else can be expected but death? Hence, all deaths from Shanghan are inevitably due to the prior failure of Yuan Qi. This is a universal malpractice.
Therefore, in clinical practice, whenever one observes weak and spiritless pulses, deafness, trembling hands, mental fatigue, timidity of Qi, aversion to cold with a preference for dim environments, faint speech, and bluish-white complexion—all signs indicating insufficiency—one must prioritize protecting Yuan Qi. If the constitution is inherently deficient and one over-disperses the exterior, Yang collapse will ensue; if the Zang-Fu Qi is inherently deficient and one mistakenly purges the interior, Yin collapse will result. Those who commit these errors will surely die. For instance, if Yuan Qi is half-deficient while the pathogen is vigorous, one must weigh the severity and combine tonification with dispersion to achieve appropriateness. If Yuan Qi is severely deficient, even if the pathogen is vigorous, it must not be attacked; instead, one must carefully distinguish Yin and Yang and vigorously tonify Middle Qi. For example, if a person occasionally contracts Yin-Cold while generally healthy, and the pathogen has not penetrated deeply, presenting only with fever and body ache, a rapid but non-voluminous pulse, no internal heat signs, and an inherent constitutional weakness, one should use Liyin Decoction (Nourish Yin Decoction) added with Chai Hu (Bupleuri Radix), or added with Ma Huang (Ephedrae Herba), administered continuously for one or two doses. The effect is miraculous; this is the primary commonly used formula.
For other conditions: if the deficiency is in the Yang aspect, formulas such as Si Chai Hu Yin (Four Bupleuri Drink), Buzhong Yiqi Tang (Tonify the Middle and Augment the Qi Decoction), Bazhen Tang (Eight Treasure Decoction), Lizhong Tang (Regulate the Middle Decoction), or Wenwei Yin (Warm the Stomach Drink) should be employed. This represents the treatment of warming the middle to facilitate spontaneous dispersion. If the deficiency is in the Yin aspect, characterized by depletion of fluids and water insufficiency preventing sweating, one should use Buyin Yiqi Jian (Tonify Yin and Augment Qi Infusion), San Chai Hu Yin (Three Bupleuri Drink), Sanyin Jian (Three Yin Infusion), or Zuogui Yin (Left Restoring Drink). This embodies the treatment of strengthening Water to control Yang, transforming Essence into Qi. In cases of Yin Excess repelling Yang, presenting as True Cold and False Heat, one should use Dabu Yuan Jian (Great Tonification of the Origin Infusion), Yougui Yin (Right Restoring Drink), or the ingredients of Cui Shi Bawei Wan (Cui’s Eight-Ingredient Pill). This constitutes the treatment of guiding Fire back to its source.
Regarding patterns of Yin Excess and Yang Decline, where the body may feel hot but aversion to cold persists, accompanied by nausea/vomiting, diarrhea, a back feeling cold as ice, or cold extremities, these indicate extreme Yang deficiency. One must unhesitatingly use Dawenzhong Yin (Great Warming of the Middle Drink) or Liyin Jian (Nourish Yin Infusion). If, however, the pathogenic heat is intense and fluids are dried up, cool water may be used gradually to resolve the heat. If the exterior pathogen remains unresolved while the interior is closed and stagnant, mild resolving methods may be combined to gradually dispel the cold. If the pathogen is Excessive while the Righteous Qi is Deficient, creating a situation where the host cannot overpower the guest, if one can secure the Root and prevent rupture, the pathogen will resolve without battle. There is profound subtlety in this approach. Over fifty years, I have saved numerous lives using these principles. I record this cautiously as a standard for universal benefit.