仲景曰∶太阳中风，脉浮紧，发热恶寒身疼痛，不汗出而烦躁者，大青龙主之。
麻黄（六两，去节） 桂枝（二两） 甘草（二两，炙） 杏仁（四十枚，去皮尖） 生姜（三
两，切） 大枣（十二枚，去核） 石膏（如鸡子大一块，捣碎） 水九升，先煮麻黄，
减二升，去上沫，纳诸药，煮取三升，温服一升，取微汗，一服汗，停后服。
成氏曰∶此中风见寒脉也。浮则为风，风则伤卫，紧则为寒，寒则伤荣，荣卫俱
病，故发热恶寒，身疼痛也。风并于卫者，为荣弱卫强，寒并于荣者，为荣强卫弱，今
风寒两伤，则荣卫俱实，故不出汗而烦躁也。青龙者，东方甲乙木神也，专主生发之
令，万物出甲，开甲，则有两歧，肝有两叶，以应之，所以谓之青龙。中风脉浮紧，
为中风见寒脉，伤寒脉浮缓，为伤寒见风脉，是风寒两伤也。桂枝汤解肌以祛风，而
不能已其寒，麻黄汤发汗以散寒，而不能去其风，故特取大青龙以两解之。麻黄甘温，
桂枝辛热，寒则伤荣，以甘缓之，风则伤卫，以辛散之，故麻黄为君，桂枝为臣也。
甘草甘平，杏仁甘苦，苦甘为助佐，麻黄以发表，大枣甘温，生姜辛温，辛甘相合，佐
桂枝以解肌，石膏辛甘微寒，夫风阳邪也，寒阴邪也，风伤阳，寒伤阴，阴阳两伤，非
轻剂所能独散也，必须轻重之药同散之。是以石膏为使，而专达肌表也。陶氏曰∶此汤
险峻，须风寒俱甚，又加烦躁方可与之，不如桂枝麻黄各半汤为稳，桂枝麻黄各半汤
者，即二方合用是也。
Zhang Zhongjing stated: In Taiyang Wind-Strike (Taiyang Fengzhong, a syndrome caused by wind pathogen invading the Taiyang channel), if the pulse is floating and tight, accompanied by fever, aversion to cold, body pain, absence of sweating, and irritability, Da Qing Long Tang (Great Blue Dragon Decoction) should be administered.
Ephedrae Herba (Mahuang, 麻黄) (6 liang, remove joints), Cinnamomi Ramulus (Guizhi, 桂枝) (2 liang), Glycyrrhizae Radix et Rhizoma (Gancao, 甘草) (2 liang, honey-fried), Armeniacae Semen Amarum (Xingren, 杏仁) (40 seeds, remove skin and tips), Zingiberis Rhizoma Recens (Shengjiang, 生姜) (3 liang, sliced), Jujubae Fructus (Dazao, 大枣) (12 seeds, remove pits), Gypsum Fibrosum (Shigao, 石膏) (one piece as large as a chicken egg, crushed). Use nine sheng of water. First decoct Mahuang, reduce by two sheng, skim off the foam on the surface, then add the remaining herbs. Decoct until three sheng remain. Take one sheng warm. The goal is slight sweating. If sweating occurs after the first dose, stop taking the remaining medicine.
Cheng Wuji stated: This presents a Wind-Strike syndrome with a Cold-pulse. Floating indicates Wind; Wind damages Wei Qi (Defensive Qi). Tight indicates Cold; Cold damages Ying Blood (Nutritive Blood). Since both Ying and Wei are diseased, fever, aversion to cold, and body pain occur. When Wind predominates in the Wei level, it results in weak Ying and strong Wei. When Cold predominates in the Ying level, it results in strong Ying and weak Wei. Now, since both Wind and Cold injure simultaneously, both Ying and Wei become excess/replete, leading to anhidrosis and irritability. "Qing Long" (Azure Dragon) refers to the spirit of Wood (Jia and Yi stems) in the East, which governs the command of growth and sprouting. When all things emerge from the soil, breaking the shell often yields two divisions; the liver has two lobes, corresponding to this, hence named Azure Dragon. A floating-tight pulse in Wind-Strike indicates Wind-Strike presenting with Cold-pulse characteristics; a floating-slow pulse in Cold Damage indicates Cold Damage presenting with Wind-pulse characteristics. This constitutes injury by both Wind and Cold. Gui Zhi Tang (Cinnamon Twig Decoction) releases the muscle layer to dispel Wind but cannot resolve Cold. Ma Huang Tang (Ephedra Decoction) induces sweating to scatter Cold but cannot eliminate Wind. Therefore, Da Qing Long Tang is specifically chosen to resolve both simultaneously. Mahuang is sweet and warm; Guizhi is acrid and hot. Since Cold damages Ying, sweet properties are used to moderate it; since Wind damages Wei, acrid properties are used to disperse it. Thus, Mahuang is the Sovereign herb, and Guizhi is the Minister herb. Gancao is sweet and neutral; Xingren is bitter and sweet. Bitter and sweet combinations assist as Adjuvant herbs; Mahuang is used to release the exterior. Dazao is sweet and warm; Shengjiang is acrid and warm. Acrid and sweet combined assist Guizhi in releasing the muscle layer. Shigao is acrid, sweet, and slightly cold. Wind is a Yang pathogen; Cold is a Yin pathogen. Wind injures Yang; Cold injures Yin. When both Yin and Yang are injured, light agents alone cannot disperse them; heavy and light herbs must be used together for dispersion. Therefore, Shigao serves as the Envoy herb, specifically reaching the muscle and exterior. Tao Hua stated: This decoction is dangerous and potent. It should only be given when both Wind and Cold are severe and accompanied by irritability. It is safer to use Gui Zhi Ma Huang Ge Ban Tang (Half Gui Zhi Half Ma Huang Decoction), which is simply the combination of the two aforementioned formulas.