仲景《伤寒》一书，乃统治外感之书，非专治风寒者也。六经分明，寒温疫三证，均
晓然矣。兹录提纲于下曰∶“太阳之为病，脉浮，头痛，项强，而恶寒。”“阳明之为病，胃
家实是也。”“少阳之为病，口苦，咽干，目眩，耳聋。”“太阴之为病，腹痛，自利，时
时呕吐。”“少阴之为病，但欲寐是也。”“厥阴之为病，消渴，气上冲胸，饥不欲食，食
则吐蛔，下之利不止。”
无论外感内伤，无论出其右者，莫六字若也。曰表，里，寒，热，虚，实。三阳为
表，三阴为里。表中之里，阳明是也，里中之表，少阴是也。并各相表里。三阳之腑主
表，经主里。三阴则心肺主表，脾肝肾主里。外感者表宜汗，里宜下。内伤者表宜清补，里
宜温补。内伤阳则阴盛，阴盛者易感寒。内伤阴则阳亢，阳亢者易感热。此所谓邪乘虚
入也，虚为正虚，实乃邪实。故经云∶“邪气盛则实，精气夺则虚。”医能将此参伍错综，
条分缕晰，则亦庶乎其可也。
风
风有内外。内动之风病于肝，治当辛凉。
外感之风病在肺，治当温散。兼寒脉紧，兼湿脉弦，燥化脉数，寒化脉迟，本病脉浮。
寒
寒有表里，而表里各有虚实。实者解表，宜麻黄汤，攻里宜三物白散。虚者固表，宜
桂枝汤，温里宜四逆汤。兼风脉浮，兼湿脉沉。
暑
天热地湿，合而成证，暑气当令，因时命名，邪实脉洪，正虚脉濡。
湿
湿有清浊。露雾湿伤气分者曰清，潮水湿伤血分者曰浊，清宜发汗，浊宜利水。从
燥化则脉急，从寒化则脉缓，本病脉滑。
燥
燥有虚实，虚燥救肺，实燥泻心，酸甘凉润，始终正治，邪实脉涩，正虚脉短。
火
火有阴阳，阳火可釜底抽薪，阴火宜导龙归海，阳脉有力，阴脉无神。
张仲景的《伤寒论》一书，是统管治疗外感疾病的著作，并非专门治疗风寒病的书。六经辨证界限分明，寒证、温病、疫病三种证候，都清晰明了。现摘录其提纲如下：“太阳病（太阳经受邪所致的病证）的特征是：脉象浮，头痛，项部僵硬，并且恶寒。”“阳明病（阳明经受邪或腑实热结的病证）的特征是：胃家实（胃肠燥热结实）。”“少阳病（少阳经受邪的病证）的特征是：口苦，咽干，目眩，耳聋。”“太阴病（太阴脾经虚寒的病证）的特征是：腹痛，自发性腹泻，时常呕吐。”“少阴病（少阴心肾虚衰的病证）的特征是：只想睡觉（精神萎靡）。”“厥阴病（厥阴肝经寒热错杂的病证）的特征是：口渴多饮，气向上冲至胸部，饥饿但不想进食，进食则吐出蛔虫，若误用攻下法则腹泻不止。”
无论是外感疾病还是内伤疾病，无论病情表现如何，没有比这六个字更精辟的了。即：表、里、寒、热、虚、实。三阳经属于表，三阴经属于里。表之中的里，指的是阳明；里之中的表，指的是少阴。它们各自互为表里关系。三阳经的腑主表，经主里。三阴经则心肺主表，脾肝肾主里。对于外感病，表证适宜发汗解表，里证适宜攻下泄热。对于内伤病，表证适宜清补，里证适宜温补。内伤导致阳气受损则阴气偏盛，阴气偏盛者容易感受寒邪。内伤导致阴气受损则阳气亢盛，阳气亢盛者容易感受热邪。这就是所谓的“邪气乘虚而入”，这里的“虚”是指正气虚弱，“实”是指邪气盛实。所以经典说：“邪气盛实则为实证，精气耗损则为虚证。”医生如果能将上述理论错综参悟，条理清晰地分析辨析，那么也就差不多可以胜任了。
风
风邪有内风和外风之分。内生的风邪病变在肝脏，治疗应当使用辛凉之法。外感的风邪病变在肺脏，治疗应当使用温散之法。兼夹寒邪则脉象紧，兼夹湿邪则脉象弦，化燥则脉象数，化寒则脉象迟，本病脉象浮。
寒
寒邪有表寒和里寒之分，而表里各有虚实。实证解表，适宜用麻黄汤，攻里适宜用三物白散。虚证固表，适宜用桂枝汤，温里适宜用四逆汤。兼夹风邪脉象浮，兼夹湿邪脉象沉。
暑
天气炎热地面潮湿，二者结合形成证候，暑气当令，因时令而得名，邪气盛实则脉象洪大，正气虚弱则脉象濡软。
湿
湿邪有清浊之分。露雾般的湿邪伤害气分的称为清湿，如潮水般的湿邪伤害血分的称为浊湿，清湿适宜发汗，浊湿适宜利水。从燥化则脉象急，从寒化则脉象缓，本病脉象滑。
Zhang Zhongjing's *Treatise on Cold Pathogenic Diseases* (*Shanghan Lun*) is a work that comprehensively governs the treatment of exogenous diseases, rather than being exclusively for treating wind-cold pathogens. The differentiation of the Six Channels (Liu Jing) is clear and distinct; thus, the patterns of cold diseases, warm diseases, and epidemics are all made evident. The following outlines are recorded here: "The characteristic of Taiyang disease (disease of the Taiyang channel) is a floating pulse, headache, stiffness of the neck, and aversion to cold." "The characteristic of Yangming disease (disease of the Yangming channel or fu-organ excess heat) is 'stomach-house excess' (gastric-intestinal dryness-heat accumulation)." "The characteristic of Shaoyang disease (disease of the Shaoyang channel) is bitter taste in the mouth, dry throat, vertigo, and deafness." "The characteristic of Taiyin disease (deficiency-cold disease of the Taiyin spleen channel) is abdominal pain, spontaneous diarrhea, and frequent vomiting." "The characteristic of Shaoyin disease (deficiency disease of the Shaoyin heart-kidney) is merely desiring sleep (mental lethargy)." "The characteristic of Jueyin disease (mixed cold-heat disease of the Jueyin liver channel) is excessive thirst, qi rushing up to the chest, hunger without desire to eat, vomiting roundworms after eating, and if purgatives are misused, diarrhea will not cease."
Regardless of whether it is an exogenous or endogenous disease, regardless of its manifestation, nothing surpasses these six characters: Exterior (Biao), Interior (Li), Cold (Han), Heat (Re), Deficiency (Xu), and Excess (Shi). The Three Yang channels belong to the Exterior, and the Three Yin channels belong to the Interior. The Interior within the Exterior refers to Yangming; the Exterior within the Interior refers to Shaoyin. They each have a mutual exterior-interior relationship. The Fu organs of the Three Yang govern the Exterior, while their Jing channels govern the Interior. For the Three Yin channels, the Heart and Lung govern the Exterior, while the Spleen, Liver, and Kidney govern the Interior. For exogenous diseases, Exterior patterns are suitable for diaphoresis (sweating method), and Interior patterns are suitable for purgation. For endogenous injuries, Exterior patterns are suitable for clearing and tonifying, while Interior patterns are suitable for warming and tonifying. Endogenous injury leading to yang deficiency results in yin excess; those with yin excess are prone to contracting cold pathogens. Endogenous injury leading to yin deficiency results in yang hyperactivity; those with yang hyperactivity are prone to contracting heat pathogens. This is what is meant by "pathogens entering due to deficiency." Here, "deficiency" refers to the weakness of healthy qi, and "excess" refers to the abundance of pathogenic factors. Thus, the classics state: "When pathogenic factors are abundant, it is an Excess pattern; when essence and qi are depleted, it is a Deficiency pattern." If physicians can comprehend and intricately analyze these principles, distinguishing them clearly and logically, they will be sufficiently competent.
Wind
Wind pathogens have internal and external origins. Internal wind pathology affects the Liver; treatment should employ acrid-cool methods. External wind pathology affects the Lungs; treatment should employ warm-dispersing methods. Accompanied by cold, the pulse is tight; accompanied by dampness, the pulse is wiry; transforming into dryness, the pulse is rapid; transforming into cold, the pulse is slow; the primary disease presents with a floating pulse.
Cold
Cold pathogens have Exterior and Interior aspects, each having Deficiency and Excess types. In Excess cases, resolve the Exterior using Mahuang Tang (Ephedra Decoction); attack the Interior using Sanwu Baisan (Three-Ingredient White Powder). In Deficiency cases, consolidate the Exterior using Guizhi Tang (Cinnamon Twig Decoction); warm the Interior using Sini Tang (Frigid Extremities Decoction). Accompanied by wind, the pulse is floating; accompanied by dampness, the pulse is deep.
Summerheat
Hot weather and humid ground combine to form a syndrome. Summerheat is prevalent according to the season, hence named accordingly. When pathogenic factors are excess, the pulse is surging; when healthy qi is deficient, the pulse is soggy.
Dampness
Dampness has Clear and Turbid distinctions. Dew-like dampness injuring the Qi level is called Clear dampness; tide-like dampness injuring the Blood level is called Turbid dampness. Clear dampness is suitable for diaphoresis; Turbid dampness is suitable for promoting urination. Transforming into dryness, the pulse is urgent; transforming into cold, the pulse is slow; the primary disease presents with a slippery pulse.
Dryness
Dryness has Deficiency and Excess types. Deficient dryness rescues the Lungs; Excess dryness drains the Heart. Using sour-sweet cool-moistening methods constitutes the standard correct treatment. Pathogenic excess presents with a choppy pulse; healthy qi deficiency presents with a short pulse.
Fire
Fire pathogens have Yin and Yang distinctions. Yang fire can be treated by "drawing firewood from under the cauldron" (clearing heat and draining fire); Yin fire is suitable for "guiding the dragon back to the sea" (nourishing yin and descending fire). Yang fire presents with a forceful pulse; Yin fire presents with a pulse lacking spirit.