伤寒劳复。何以明之。劳为劳动之劳。复为再发也。是伤寒瘥后。因劳动再发者是
也。伤寒新瘥后。血气未平。余热未尽。劳动其热。热气还经络。遂复发也。此有二种。
一者因劳动外伤。二者因饮食内伤。其劳动外伤者。非止强力摇体。持重远行之
劳。至于梳头洗面则动气。忧悲思虑则劳神。皆能复也。况其过用者乎。其饮食内
伤者。为多食则遗。食肉则复者也。内经曰。热病已愈。而时有遗者何也。以热甚而
强食之。病已衰而热有所藏。因其谷气留薄。两阳相合。故有所遗。经曰。病已瘥尚
微烦。设不了了者。以新虚不胜谷气。故令微烦。损谷则愈。夫伤寒邪气之传。自表
至里。有次第焉。发汗吐下。自轻至重。有等差焉。又其劳复则不然。见其邪气之复
来也。必迎夺之。不待其传也。经曰。大病瘥后劳复者。枳实栀子豉汤主之。若有宿
食加大黄。且枳实栀子豉汤则吐之。岂待虚烦懊 之证。加大黄则下之。岂待腹
满谵语之候。经曰。伤寒瘥后更发热者。小柴胡汤主之。脉浮以汗解之。脉沉实者。
以下解之。亦是便要折其邪也。盖伤寒之邪。自外入也。劳复之邪。自内发也。发汗
吐下。随宜施用焉。呜呼。劳复也。食复也。诸劳皆可及。御内则死矣。若男女相易。则
为阴阳易。其不易自病者。谓之女劳复。以其内损真气。外动邪热。真虚邪盛。则不
可治矣。昔督邮顾子献。不以华敷之诊为信。临死致有出舌数寸之验。由此观之。
岂不与后人为鉴诫哉。
伤寒劳复，该如何阐明呢？“劳”指劳动，“复”指再次发作。所谓劳复，是指伤寒病愈之后，因劳动而再次发作的情况。
伤寒刚刚痊愈时，气血尚未平复，余热尚未清除。劳动会扰动体内的热气，使热气回流至经络，从而导致疾病复发。这种情况主要有两种：一是因劳动导致的外伤（外感/劳损），二是因饮食不当导致的内伤。
对于因劳动导致的外伤而言，不仅仅是指用力摇动身体、背负重物或长途行走这类体力劳动；即使是梳头、洗脸这样的小事也会耗动气机，忧愁悲伤、思虑过度则会劳损心神，这些都能导致疾病复发，更何况是过度劳累的人呢？
对于因饮食导致的内伤而言，主要是多吃导致病情遗留（遗），吃肉导致疾病复发（复）。《内经》说：“热病已经痊愈，但时常有遗留症状，这是为什么呢？”这是因为热势正盛时强行进食，虽然病症看似衰退，但热量被蕴藏在内。由于食物之气滞留体内，与残留的热邪相结合，两阳相合，所以会有遗留症状。经文又说：“病已痊愈但仍感觉轻微心烦，神情不爽快，这是因为新近体虚，无法承受谷气的运化，所以导致轻微心烦。减少饮食即可痊愈。”
伤寒邪气的传变，从表到里，是有次序的；发汗、催吐、泻下等治法，从轻到重，是有等级的。然而劳复则不然，当看到邪气再次袭来时，必须立即迎头痛击，不能等待其传变。经文说：“大病痊愈后因劳复者，用枳实栀子豉汤主治。如果有宿食停滞，加大黄。”既然枳实栀子豉汤是用来涌吐的，难道非要等到出现虚烦懊憹的症状才使用吗？既然大黄是用来攻下的，难道非要等到出现腹部胀满、胡言乱语的症状才使用吗？
经文说：“伤寒痊愈后再次发热者，用小柴胡汤主治。脉浮的，用发汗法解除；脉沉实的，用泻下法解除。”这也是为了迅速遏制邪气。大概伤寒的邪气是从外部侵入的，而劳复的邪气是从内部发出的。发汗、催吐、泻下等治法，应根据具体情况适宜施用。
唉！劳复、食复，各种劳累都可能引发。如果房事不节，会导致死亡。如果男女之间通过性交交换精气，称为阴阳易。如果不是这种互相传染而是自身发病的，称为女劳复。因为内损真气，外动邪热，正气虚弱而邪气强盛，就无法治疗了。
从前有一位督邮叫顾子献，不相信华敷（此处疑为华佗之误或特定医家，依原文保留）的诊断，临死时出现了舌头伸出数寸的验征。由此看来，这难道不是给后人作为鉴戒吗？
**Labor Relapse of Cold Damage**
How should Labor Relapse (Laofu, recurrence of illness due to overexertion after recovery) be explained? "Labor" refers to physical exertion, and "Relapse" refers to the recurrence of symptoms. Thus, Labor Relapse denotes the situation where cold damage recurs after recovery due to overexertion.
After cold damage has just healed, the blood and qi are not yet balanced, and residual heat has not been fully cleared. Physical exertion stirs up this heat, causing it to return to the meridians and collaterals, thereby triggering a relapse. There are two types of this condition: one is external injury caused by labor, and the other is internal injury caused by diet.
Regarding external injury from labor, it is not limited to strenuous activities such as vigorous body movement, carrying heavy loads, or traveling long distances. Even minor acts like combing hair or washing the face can disturb the qi; feelings of sorrow, grief, worry, and excessive thinking can exhaust the spirit. All these factors can lead to relapse, let alone cases of extreme overexertion.
Regarding internal injury from diet, it primarily involves "lingering" (Yi, residual symptoms due to overeating) and "relapse" (Fu, recurrence due to eating meat). The *Neijing* states: "Why do patients sometimes have lingering symptoms after a febrile disease has healed?" This occurs because food was forced upon them while the heat was intense. Although the disease seemed to subside, heat remained trapped inside. Because the qi of the grain remains stagnant and combines with the residual heat, the combination of two "yangs" leads to lingering symptoms. Another classic text says: "If the patient feels slightly vexed and uncomfortable after recovery, it is because the newly weakened body cannot handle the qi of food, causing slight vexation. Reducing food intake will lead to healing."
The transmission of pathogenic factors in cold damage proceeds from the exterior to the interior in a specific sequence. Methods such as sweating, vomiting, and purging range from mild to severe in their intensity. However, labor relapse is different. When the recurrence of pathogenic factors is observed, treatment must immediately intercept and overcome them, without waiting for further transmission. The classic text states: "For labor relapse following a major disease, Zhishi Zhizi Chitang (Bitter Orange, Gardenia, and Fermented Soybean Decoction) is the primary prescription. If there is retained food, add Dahuang (Rhubarb)." Since Zhishi Zhizi Chitang induces vomiting, must one wait for symptoms of deficiency vexation and agitation before using it? Since Dahuang induces purging, must one wait for symptoms of abdominal fullness and delirious speech before using it?
Another passage states: "For fever recurring after cold damage has healed, Xiaochaihu Tang (Minor Bupleurum Decoction) is the primary prescription. If the pulse is floating, resolve it with sweating; if the pulse is deep and solid, resolve it with purging." This is also to promptly curb the pathogen. Generally, the pathogen in cold damage enters from the exterior, whereas the pathogen in labor relapse arises from within. Treatments such as sweating, vomiting, and purging should be applied appropriately according to the circumstances.
Alas! Labor relapse and dietary relapse can be triggered by various forms of overexertion. Sexual intercourse during recovery leads to death. If pathogens are transmitted through sexual exchange between men and women, it is called Yin-Yang Exchange (Yinyangyi). If the disease arises internally without such mutual transmission, it is called Female Labor Relapse (Nulaofu). This damages the true qi internally and stirs up pathogenic heat externally. When true qi is deficient and pathogenic heat is excessive, the condition becomes incurable.
In the past, Gu Zixian, a district commissioner, did not trust the diagnosis of Hua Fu (likely referring to Hua Tuo or a specific physician context). At the time of his death, he exhibited the sign of his tongue protruding several inches. From this, we can see that it serves as a warning and lesson for future generations.