太阳证。头痛发热。自汗恶风。脉当缓而反紧。伤风得伤寒脉也。
太阳证。头痛发热无汗恶寒。脉当急而反缓。伤寒得伤风脉也。
二证脉不同本经（大青
龙汤）主之。易老（桂枝麻黄各半汤）。此言外之意。杨氏云。非明脉者不可用大青龙汤。以
其有厥逆筋惕肉 及亡阳之失也。故易老改为九味羌活汤。而不用桂枝麻黄也。羌活汤不论
有汗无汗。悉宜服之。但有缓急不同矣。九味羌活汤药证加减。服饵缓急。具见于后。
太阳证。发热恶寒自汗脉缓。太阳证。发热恶风无汗脉缓。此易老元将麻黄一桂枝
二治上二证后复改用羌活汤。
太阳膀胱脉浮紧直至寸口。所以头痛者。头与寸口俱高之分也。兼厥阴与督脉会于巅。
逆太
阳之经上而不得下。故壅滞为头痛于上也。左手浮弦胸中痛也。沉弦背愈痛右手浮弦者亦然
。
头痛者木也最高之分惟风可到风则温也。治以辛凉。秋克春之意。故头痛皆以风药治之者。
总其体之常也。然各有三阴三阳之异焉。故太阳则宜川芎。阳明则宜白芷少阳则宜柴胡。太
阴则宜苍术。少阴则宜细辛。厥阴则宜吴茱萸也。
假令治太阳阳明。不可遗太阳而只用阳明药余仿此用三阳经解药后身番覆重者。若烦则
是有阳
明也。若不烦而番覆轻者。知不传三阴也。不传三阴则为解也。大抵三阴之体静重与湿相同
。伤寒五日后无汗。谓谷消水去形亡故下之。三日前谓内有水谷故汗之。
太阳病证。表现为头痛、发热，自汗出，怕风，脉象应当迟缓却反而紧束。这是伤风之证却出现了伤寒的脉象。
太阳病证。表现为头痛、发热，无汗，怕冷，脉象应当紧急却反而迟缓。这是伤寒之证却出现了伤风的脉象。
上述两种证候脉象不同，本经（此处指代前文语境中的某一经络或理论体系，原文可能有脱漏，结合下文“大青龙汤”推测可能涉及表实无汗重症）以大青龙汤为主治方剂。易老（张元素）使用桂枝麻黄各半汤。这是言外之意。杨氏说，不精通脉诊的人不可使用大青龙汤，因为若误用会导致四肢厥逆、筋肉跳动以及亡阳等失误。所以易老将其改为九味羌活汤，而不使用桂枝和麻黄。九味羌活汤不论有汗无汗，都适宜服用，只是服药的缓急程度有所不同罢了。九味羌活汤的药物与证候加减，以及服用的缓急方法，详细记载在后文。
太阳病证。发热、怕冷、自汗、脉迟缓；太阳病证。发热、怕风、无汗、脉迟缓。这是易老最初打算用一份麻黄配两份桂枝来治疗上述两种证候，后来改用羌活汤。
足太阳膀胱经的脉象浮紧，一直延伸到寸口部位。之所以出现头痛，是因为头部与寸口都属于人体高位的部位。同时，足厥阴肝经与督脉交会于头顶。邪气逆着太阳经脉向上运行而不能下行，因此壅滞于上部而导致头痛。左手脉浮弦，胸中疼痛；沉取见弦脉，背部更加疼痛。右手脉浮弦的情况也是如此。
头痛属于木行（肝），位于人体最高处，只有风邪能够到达，风邪性质属温。治疗应用辛凉药物，这是秋季克制春季（金克木）的意思。所以头痛都用风药治疗，是总结其常态。然而，各经又有三阴三阳的区别。所以太阳经头痛适宜用川芎，阳明经头痛适宜用白芷，少阳经头痛适宜用柴胡，太阴经头痛适宜用苍术，少阴经头痛适宜用细辛，厥阴经头痛适宜用吴茱萸。
假如治疗太阳阳明合病，不可遗漏太阳经而只使用治疗阳明经的药物，其余类推。在使用三阳经解表药后，如果身体翻覆不安且沉重，如果有烦躁，说明病已传入阳明经。如果不烦躁且翻覆较轻，可知病未传入三阴经。未传入三阴经即为病解。大致来说，三阴经的体质特点是静重，与湿邪相似。伤寒五日后无汗，是因为谷气消减、水液排尽、形体枯竭，所以采用攻下法。伤寒三日前，是因为体内还有水谷，所以采用发汗法。
Taiyang syndrome. Headache and fever, spontaneous sweating, aversion to wind, the pulse should be slow but is instead tight. This is a Wind-strike pattern presenting with a Cold-strike pulse.
Taiyang syndrome. Headache and fever, no sweating, aversion to cold, the pulse should be rapid/tight but is instead slow. This is a Cold-strike pattern presenting with a Wind-strike pulse.
The pulses for these two patterns differ; this meridian (context implies a specific condition or text reference) is primarily treated with Da Qing Long Tang (Great Blue Dragon Decoction). Yi Lao (Zhang Yuansu) uses Gui Zhi Ma Huang Ge Ban Tang (Cinnamon Twig and Ephedra Half-Dose Decoction). This conveys an implied meaning. Yang Shi stated that those who do not clearly understand pulse diagnosis must not use Da Qing Long Tang, because misuse can lead to complications such as limb reversal (Jue Ni), muscle twitching, and Yang collapse. Therefore, Yi Lao changed it to Jiu Wei Qiang Huo Tang (Nine-Ingredient Notopterygium Decoction), avoiding Gui Zhi (Cinnamon Twig) and Ma Huang (Ephedra). Jiu Wei Qiang Huo Tang is suitable regardless of whether there is sweating or not, differing only in the urgency of administration. The modifications of herbs and syndromes for Jiu Wei Qiang Huo Tang, along with the details of administration timing, are presented later.
Taiyang syndrome: fever, aversion to cold, spontaneous sweating, slow pulse. Taiyang syndrome: fever, aversion to wind, no sweating, slow pulse. This refers to Yi Lao initially intending to treat the above two patterns with one part Ma Huang (Ephedra) and two parts Gui Zhi (Cinnamon Twig), but subsequently switching to Qiang Huo Tang (Notopterygium Decoction).
The pulse of the Foot-Taiyang Bladder Meridian is floating and tight, extending all the way to the Cun Kou (Radial Pulse Position). The reason for headache is that both the head and the Cun Kou are located at high points of the body. Additionally, the Foot-Jueyin Liver Meridian and the Du Mai (Governing Vessel) intersect at the vertex. Pathogenic factors reverse up along the Taiyang meridian and cannot descend, causing stagnation in the upper part and resulting in headache. A floating and wiry pulse on the left hand indicates chest pain; a deep and wiry pulse indicates increased back pain. The same applies to a floating and wiry pulse on the right hand.
Headache is associated with Wood (Liver), located at the highest point, accessible only by Wind pathogen, which has a warm nature. Treatment employs Acrid-Cool herbs, reflecting the principle of Autumn overcoming Spring (Metal overcoming Wood). Thus, headaches are generally treated with Wind-dispelling herbs, summarizing their common characteristic. However, there are differences among the Three Yin and Three Yang meridians. Therefore, for Taiyang headache, Chuan Xiong (Ligusticum Rhizome) is suitable; for Yangming headache, Bai Zhi (Angelica Dahurica Root) is suitable; for Shaoyang headache, Chai Hu (Bupleurum Root) is suitable; for Taiyin headache, Cang Zhu (Atractylodes Rhizome) is suitable; for Shaoyin headache, Xi Xin (Asarum Root) is suitable; for Jueyin headache, Wu Zhu Yu (Evodia Fruit) is suitable.
For example, when treating Taiyang-Yangming combined disease, one must not neglect the Taiyang meridian and use only Yangming herbs; apply this logic to others. After administering resolving herbs for the Three Yang meridians, if the patient tosses and turns heavily, restlessness indicates involvement of the Yangming meridian. If there is no restlessness and tossing/turning is mild, it is known that the disease has not transmitted to the Three Yin meridians. If it does not transmit to the Three Yin meridians, the disease is resolving. Generally, the constitution of the Three Yin meridians is quiet and heavy, similar to Dampness. In Cold-strike disease, after five days without sweating, it means grain essence is depleted, fluids are gone, and the form is wasted, so purgative methods are used. Within three days, it means water and grain remain inside, so diaphoretic methods are used.