背为阳，腹为阴。背恶寒者，阳气不足，阴寒气盛故也。若风寒在表而恶寒，则一身尽寒矣。若阳气衰，
阴气盛，寒邪在里，口中和，无热而背恶寒者，属少阴也，宜温之，附子汤主之。若阴气微，阳气威，热邪
陷内，口燥热而背恶寒者，属阳明也，宜清之，白虎加人参汤主之。三者均自巨恶寒也，有阴阳寒热
之不同，而于口中润燥得之。
恶风者，见风则怕，在密室之中，无所恶也。盖因风邪伤卫，卫气虚弱，腠理不密，所以汗出而恶风也。
然卫气者，能温分肉、充皮肤、肥腠理、司开阖者也。若风邪中于卫，则必恶风，何也。风则伤卫，寒则伤
营，卫为风邪所中，分肉不温而热矣，皮毛不充而缓矣，腠理失其肥，则□而不密，开阖失其司，则泄
而不固，是以恶风也。然恶风恶寒二症，均为表症，以恶风与恶寒比之，恶寒者，啬啬然而憎寒即不
当风而自恶寒。其恶风者，得居密室之中，帏帐之内，舒缓而无所畏也，或用扇，或当风，则淅淅然而
恶，此为恶风也。恶寒，有属于阳，有属于阴，若是恶风，悉属于阳，非若恶寒有阴阳之别也，故三阴之
症，并无恶风者是也。然恶风虽悉属表，而发散又有不同。若无汗而恶风，为伤寒，当发其汗。汗出而
恶风，为中风，当解其肌。若下症悉具，而恶风未罢者，当先解其外也。又有汗多亡阳与风湿，皆有恶
风之症。若发活过多，遂漏不止，卫虚亡阳，恶风脉浮者，必以桂枝加术附阳温其经而固其卫。若风
湿相搏，骨节烦疼，湿胜自汗，皮腠不密，恶风短气，必用甘草附子汤散其湿而固其卫。由是观之，恶
风属卫，明矣。
背部属阳，腹部属阴。背部怕冷，是因为阳气不足，阴寒之气过盛所致。如果是风寒邪气在体表引起的怕冷，那么全身都会感到寒冷。如果阳气衰微，阴气偏盛，寒邪在体内，口中感觉平和（不苦不燥），没有发热而仅背部怕冷，这属于少阴病（少阴经受邪所致的病证），应当用温法治疗，以附子汤为主方。如果阴气微弱，阳气亢盛，热邪陷入体内，口干燥且感觉热，同时背部怕冷，这属于阳明病（阳明经受邪所致的病证），应当用清法治疗，以白虎加人参汤为主方。这三种情况虽然都表现为严重的怕冷，但存在阴阳、寒热的不同，可以通过观察口腔的湿润与干燥来辨别。
所谓恶风，是指见到风就害怕，在密闭的房间内则没有这种恐惧感。这是因为风邪损伤了卫气（运行于脉外，具有防御外邪、温养肌肤作用的气），导致卫气虚弱，腠理（皮肤纹理及汗孔）不紧密，所以出现出汗且怕风的症状。卫气的作用，是温煦肌肉、充实皮肤、使腠理致密、主管汗孔的开合。如果风邪侵袭卫气，必然会出现怕风的症状，为什么呢？因为风邪伤卫，寒邪伤营（运行于脉中，具有营养作用的气）。卫气被风邪侵袭，肌肉失去温煦而发热，皮毛得不到充养而松弛，腠理失去其致密性，变得疏松而不紧密，开合功能失调，导致津液泄出而不能固摄，因此产生怕风的症状。然而，恶风和恶寒这两种症状，都属于表证。比较恶风和恶寒，恶寒的人，神情畏缩，即使不面对风也自然感到寒冷；而恶风的人，居住在密室之中或帷帐之内，舒缓自在而没有畏惧感，但如果使用扇子扇风或直接吹到风，就会瑟瑟发抖地感到害怕，这就是恶风。恶寒，有属于阳证的，也有属于阴证的；若是恶风，则全部属于阳证，不像恶寒那样有阴阳的区别，所以三阴病（太阴、少阴、厥阴病）中并没有恶风的症状。然而，恶风虽然都属于表证，但发散治疗方法又有不同。如果没有汗且怕风，属于伤寒，应当发汗解表。如果有汗且怕风，属于中风，应当调和肌表。如果具备了下法的指征，但怕风的症状仍未消除，应当先解除体表的邪气。另外，汗多导致亡阳（阳气极度耗损）和风湿病，都有怕风的症状。如果发汗过多，导致汗漏出不止，卫气虚弱导致亡阳，出现怕风且脉浮，必须用桂枝加术附汤（桂枝汤加白术、附子）温经助阳并固护卫气。如果风邪与湿邪相互搏结，骨节剧烈疼痛，湿气重导致自汗，皮肤腠理不紧密，怕风且短气，必须用甘草附子汤散除湿邪并固护卫气。由此看来，恶风归属于卫气病变，是很明显的。
The back belongs to Yang, and the abdomen belongs to Yin. Aversion to cold in the back is due to insufficiency of Yang Qi and excess of Yin-Cold pathogenic factors. If aversion to cold is caused by Wind-Cold pathogens at the exterior, the entire body will feel cold. If Yang Qi is depleted and Yin Qi is excessive, with Cold pathogens inside the interior, the mouth feels neutral (neither bitter nor dry), there is no fever, but only aversion to cold in the back; this belongs to Shaoyin Disease (diseases affecting the Shaoyin meridians). It should be treated with warming methods, primarily using Fuzi Tang (Aconite Decoction). If Yin Qi is slight and Yang Qi is vigorous, with Heat pathogens sinking into the interior, the mouth is dry and hot, yet there is aversion to cold in the back; this belongs to Yangming Disease (diseases affecting the Yangming meridians). It should be treated with clearing methods, primarily using Baihu Jia Renshen Tang (White Tiger Decoction plus Ginseng). Although all three conditions manifest as severe aversion to cold, they differ in terms of Yin/Yang and Cold/Heat, which can be distinguished by observing whether the mouth is moist or dry.
"Aversion to wind" refers to fear upon seeing wind; in a sealed room, there is no such fear. This occurs because Wind pathogens damage Wei Qi (defensive Qi that circulates outside the vessels and defends against external pathogens), leading to weakness of Wei Qi and laxity of Couli (skin texture and sweat pores), resulting in sweating and aversion to wind. The function of Wei Qi is to warm the muscles, fill the skin, make Couli dense, and regulate the opening and closing of sweat pores. If Wind pathogens invade Wei Qi, aversion to wind inevitably occurs. Why? Because Wind damages Wei Qi, while Cold damages Ying Qi (nutritive Qi that circulates within the vessels). When Wei Qi is attacked by Wind pathogens, the muscles lose warmth and become hot; the skin and hair lose nourishment and become flaccid; Couli loses its density, becoming loose and not tight; the regulation of opening and closing fails, leading to leakage without consolidation; thus, aversion to wind arises. However, both aversion to wind and aversion to cold are exterior syndromes. Comparing the two: those with aversion to cold appear timid and feel cold even without facing wind; whereas those with aversion to wind feel relaxed and unafraid when staying in a sealed room or behind curtains, but shiver with fear when fanned or exposed to direct wind—this is aversion to wind. Aversion to cold may belong to Yang syndromes or Yin syndromes; however, aversion to wind exclusively belongs to Yang syndromes, unlike aversion to cold which has Yin/Yang distinctions. Therefore, Taiyin, Shaoyin, and Jueyin diseases (collectively known as Three Yin Diseases) do not present with aversion to wind. Although aversion to wind always indicates an exterior syndrome, the dispersing treatment methods vary. If there is no sweating and aversion to wind, it is Shanghan (Cold Damage); sweating should be induced. If there is sweating and aversion to wind, it is Fengzhong (Wind Strike); the muscle layer should be harmonized. If indications for purgation are fully present but aversion to wind persists, the exterior must be resolved first. Additionally, excessive sweating leading to collapse of Yang Qi (extreme depletion of Yang Qi) and Bi syndrome (painful obstruction syndrome) caused by Wind-Dampness both present with aversion to wind. If excessive sweating leads to continuous dripping of sweat, indicating weak Wei Qi and collapse of Yang Qi, accompanied by aversion to wind and a floating pulse, Guizhi Jia Zhu Fuzi Tang (Cinnamon Twig Decoction plus Atractylodis Macrocephalae Herba and Aconiti Lateralis Radix Preparata) must be used to warm the channels, assist Yang, and secure Wei Qi. If Wind and Dampness contend with each other, causing severe joint pain, spontaneous sweating due to excess Dampness, lax Couli, aversion to wind, and shortness of breath, Gancao Fuzi Tang (Licorice and Aconite Decoction) must be used to scatter Dampness and secure Wei Qi. From this, it is clear that aversion to wind is related to Wei Qi dysfunction.