太阳之为病。脉浮头项强痛而恶寒。是恶寒乃太阳病一定之证。始而恶寒。继且发热矣
。
其恶寒与发热相兼。非如寒热往来之热时自热。寒时自寒也。所谓身大热而不欲去衣者此也
。凡风寒客于营卫之中。而洒淅恶寒者。其脉必浮。浮为在表。故曰恶寒者表未解也。虽里
证悉具。而表未解。不可攻里。必俟外解已。乃可攻也。若太阳病传入阳明者。则恶寒将自
罢。即 汗出。而不恶寒。反恶热矣。此太阳病初起发热恶寒之大概也。恶寒属表者脉必
浮。其有不浮而沉者阴病也。经云。发热恶寒者。发于阳也。无热恶寒者。发于阴也。发于
阳者病在表。宜解表为主。发于阴者病在里。宜温里为主。若阴病而误发其汗。则阳亡之变
。顷刻即至矣。阴病恶寒。以手足温者易治。手足逆冷者难治。故经云。少阴病恶寒而蜷。
时
自烦。欲去衣被者可治。又曰。少阴病恶寒身蜷而利。手足逆冷者。不治。又曰少阴病下利
。若利止恶寒而蜷卧。手足温者可治。此其义也。
恶寒属表者。在未汗以前。是谓表实。若既发汗之后。当不恶寒矣。而反恶寒者。则又
不属
实而属虚。故经云。发汗病不解。反恶寒者。虚故也。芍药甘草附子汤主之。盖以芍药甘草
两和营卫。而必藉附子以温经。则同一恶寒。而未汗以前。与既汗以后。又各不同如此。
更有里热郁盛。致阳气不得宣泄。而外恶寒者。此即内经所谓诸病恶寒。皆属于火者是
也。
辛温发表。大属非宜。而表阳被遏。其脉又多沉。与阴病相似。而又不可误于温里。其外显
假寒。内实真热。一经误用。反掌生杀。其辨之之法。则不以脉辨而以证辨。盖风寒之邪。
未经入里。口中必和。此则口中先干。其舌上燥白如积粉。甚或兼黄黑色。胸膈痞满。不大
便。或下利如深酱色。其兼厉气者。口中必有秽气。此即热甚阳郁之候。治宜宣发伏邪。使里
气通而郁阳发。则恶寒自罢。反大热而烦渴矣。然热作之后。人皆信为热。而当恶寒时。鲜
有识其为热者。不可不细心体认也。
又有背恶寒者。夫恶寒则一身皆恶。何以止称背恶寒。内经云。人身之阴阳。腹为阴。
背为
阳。背者胸中之府。诸阳受气于胸中，而转行于背。阴寒之气盛。阳虚不足御之。则背为之
恶寒。经云。少阴病一二日口中和。其背恶寒者当灸之。附子汤主之。论中口中和三字。最
宜着眼。惟其口中和。故可放胆用附子。又或乘阴气不足阳气内陷入阴中。而不转行于背。
则背亦为之微恶寒。经云。伤寒无大热。口燥渴。心烦。背微恶寒。白虎加人参汤主
之。二者治法天渊。于何辨之。亦辨之于口之渴与不渴而已矣。
The main manifestation of Taiyang disease (Disease of the Bladder and Small Intestine channels) is a floating pulse, stiffness and pain in the head and nape, and aversion to cold. This indicates that aversion to cold is a definitive symptom of Taiyang disease. Initially, there is only aversion to cold, which is subsequently followed by fever.
This simultaneous occurrence of aversion to cold and fever differs from alternating chills and fever, where one feels hot spontaneously during febrile periods and cold spontaneously during chilly periods. Here, it refers to the condition where the body has high fever yet the patient does not wish to remove clothing. Whenever wind-cold pathogens lodge within Ying (Nutritive) and Wei (Defensive) levels, causing shivering aversion to cold, the pulse must be floating. A floating pulse indicates a pathogenic process at the Exterior level; therefore, it is said that "aversion to cold signifies that the Exterior syndrome has not yet resolved." Even if Interior symptoms are fully present, as long as the Exterior syndrome remains unresolved, purgative treatment for the Interior should not be administered. One must wait until the Exterior is resolved before treating the Interior. If Taiyang disease transmits to Yangming disease (Disease of the Stomach and Large Intestine channels), the aversion to cold will cease spontaneously, accompanied by sweating, no longer aversion to cold, but rather aversion to heat. This outlines the general presentation of fever and aversion to cold at the onset of Taiyang disease.
Aversion to cold belonging to the Exterior level is characterized by a floating pulse. If the pulse is not floating but deep, it indicates a Yin disease. The Classic states: "Fever with aversion to cold indicates onset from Yang; absence of fever with aversion to cold indicates onset from Yin." Diseases originating from Yang are located at the Exterior, and treatment should primarily focus on releasing the Exterior. Diseases originating from Yin are located in the Interior, and treatment should primarily focus on warming the Interior. If a Yin disease is mistakenly treated with diaphoresis (sweating method), the variation of Yang collapse will occur instantaneously. In Yin disease with aversion to cold, if the hands and feet are warm, it is easy to treat; if the hands and feet are cold (reversal cold), it is difficult to treat. Thus, the Classic states: "In Shaoyin disease (Disease of the Kidney and Heart channels) with aversion to cold and curling up, if the patient occasionally feels vexed and desires to remove clothing and bedding, it is curable." It also states: "In Shaoyin disease with aversion to cold, curling up, and diarrhea, if the hands and feet are reversal cold, it is incurable." It further states: "In Shaoyin disease with diarrhea, if the diarrhea stops, and although there is aversion to cold and curling up, the hands and feet are warm, it is curable." This explains the principle.
Aversion to cold belonging to the Exterior level, prior to sweating, is termed an Exterior Excess syndrome. After sweating has been induced, aversion to cold should cease. If aversion to cold persists or returns after sweating, it does not belong to Excess but to Deficiency. Thus, the Classic states: "After sweating, if the disease does not resolve and aversion to cold returns, it is due to Deficiency." The formula Shaoyao Gancao Fuzi Tang (Peony, Licorice, and Aconite Decoction) is indicated. This is because Shaoyao (Paeoniae Radix Alba) and Gancao (Glycyrrhizae Radix et Rhizoma) harmonize Ying and Wei, but they rely on Fuzi (Aconiti Lateralis Radix Praeparata) to warm the meridians. Thus, although the symptom is the same (aversion to cold), the pathology differs significantly between pre-sweating and post-sweating stages.
There is also a condition where excessive interior heat stagnation prevents the dissemination of Yang Qi, resulting in external aversion to cold. This corresponds to the statement in the *Neijing* (Inner Canon): "All diseases presenting with aversion to cold mostly belong to Fire (Heat)." In such cases, using acrid-warm exterior-releasing methods is highly inappropriate. Because the Exterior Yang is constrained, the pulse often appears deep, resembling Yin disease, yet it must not be mistaken for a case requiring warming the Interior. This presents as false cold externally but true heat internally. Misapplication of warming agents can lead to death instantly. The method of differentiation relies not on the pulse but on clinical signs. Since wind-cold pathogens have not entered the Interior, the mouth typically feels normal. In contrast, this condition presents with initial dryness in the mouth. The tongue coating may be dry and white like accumulated powder, or even yellowish-black. There may be chest and diaphragm fullness and obstruction, constipation, or diarrhea with dark soy-sauce-colored stool. If accompanied by pestilential qi (epidemic toxins), the breath will have a foul odor. These are signs of severe heat and Yang constraint. Treatment should aim to vent latent pathogens, allowing Interior Qi to flow freely and constrained Yang to disperse. Consequently, aversion to cold will cease, followed by high fever, vexation, and thirst. However, once the heat erupts, people readily recognize it as heat; few can identify it as heat during the phase of aversion to cold. Careful observation is essential.
There is also a condition of isolated aversion to cold in the back. If one speaks of aversion to cold, it usually affects the whole body; why specify only the back? The *Neijing* states: "In the human body, the abdomen is Yin, and the back is Yang. The back is the mansion of the Chest organs. All Yang Qi receives energy from the Chest and circulates through the Back." When Yin-cold Qi is excessive and Yang Qi is insufficient to resist it, the back feels cold. The Classic states: "In Shaoyin disease, within one or two days, if the mouth feels normal and there is aversion to cold in the back, moxibustion should be applied, and Fuzi Tang (Aconite Decoction) should be administered." The phrase "mouth feels normal" in the commentary is crucial. Precisely because the mouth is normal, one can confidently use Fuzi. Alternatively, due to insufficiency of Yin Qi, Yang Qi may sink inward into the Yin level and fail to circulate through the back, causing slight aversion to cold in the back. The Classic states: "In Shanghan (Cold Damage) without significant fever, with dry mouth and thirst, mental restlessness, and slight aversion to cold in the back, Baihu Jia Renshen Tang (White Tiger Decoction plus Ginseng) should be administered." The therapeutic approaches for these two conditions are worlds apart. How to differentiate them? By distinguishing whether there is thirst in the mouth or not.