风伤于卫，浮缓有汗。寒伤于营，浮紧无汗。
风为阳邪，卫为阳气。风阳空疏，卫阳浮越。寒为阴邪，营为阴血。寒阴敛束，
血阴凝泣。故风必伤卫，寒必伤营者，皆类同而象似也。空疏浮越，自当有汗而脉
缓矣。（仲景桂枝汤证。）敛束凝泣，自当无汗而脉紧矣。（仲景麻黄汤证。）
暑伤于气，脉虚身热。湿伤于血，脉缓细涩。
暑亦阳邪，性热而散。伤于气分，从其类耳。阳邪伤气，气必烦蒸，故身热。
气散不敛，故脉虚。（宜清暑益气汤、加味香薷饮之类。）湿为水湿，血液相近，伤血亦从其类。
脉缓细涩，流衍渗着之象也。（宜败毒散、和剂五积散之类。）
清暑益气汤（见第十六）
十味香薷饮（见第十六）
败毒散（活人）
羌活 独活 前胡 柴胡 芎 枳壳 白茯苓 桔梗 人参（以上各一两） 甘草（半两）
上为细末，每服二钱。水一盏，入生姜二片，煎七分，温服。或沸汤点亦得。
治伤寒温疫，风湿风眩，拘蜷，风痰头疼目眩，四肢痛，憎寒壮热，项强睛疼，
及老人、小儿皆可服。或瘴烟之地，或瘟疫时行，或胸多风痰，或处卑湿脚弱，
此药不可缺也。日二、三服，以知为度。烦热口干，加黄芩。
和剂五积散 治感冒寒邪，头疼身痛，项背拘急，恶寒呕吐，或腹痛。又治伤寒发
热，头疼恶风，无问内伤生冷，外感风寒，及寒湿客于经络，腰脚 疼，及妇人经血不调，或难产并治。
白芷 茯苓 半夏（汤洗七次） 当归 芎 甘草（炙） 肉桂 芍药（各三两） 枳壳（去瓤、麸
炒） 麻黄（去节根） 陈皮（去白，各六两） 桔梗（去芦，十二两） 浓朴（去粗皮、姜制）
干姜（各四两） 苍术（泔浸、去皮，二十四两）
上 咀，每服四钱。水一盏，姜三片，葱白三根，煎七分热服。冒寒用煨姜，挟气加茱萸。妇人调经催产，加艾醋。
风邪侵袭卫分，脉象浮缓且伴有汗出。寒邪侵袭营分，脉象浮紧且无汗。
风属于阳邪，卫气属于阳气。风性开泄导致腠理空疏，卫阳之气浮越于外。寒属于阴邪，营血属于阴血。寒性收引导致气血敛束凝滞，营血运行涩滞不畅。所以风邪必定伤及卫分，寒邪必定伤及营分，这是因为同类相感、表象相似的道理。腠理空疏、卫阳浮越，自然会有汗出且脉象迟缓。（这是张仲景桂枝汤的适应证。）气血敛束、运行涩滞，自然无汗且脉象紧张有力。（这是张仲景麻黄汤的适应证。）
暑邪侵袭气分，脉象虚大且身体发热。湿邪侵袭血分，脉象缓细且涩滞。
暑也是阳邪，性质炎热而发散。伤及气分，是因其属性相同而相互感应。阳邪损伤气机，气机必然烦闷蒸腾，所以身体发热。气机散失不能收敛，所以脉象虚大。（适宜使用清暑益气汤、加味香薷饮这类方剂。）湿是水湿之邪，与血液性质相近，伤及血分也是因其属性相同而相互感应。脉象缓细涩滞，是湿气流衍渗着的表现。（适宜使用败毒散、和剂五积散这类方剂。）
清暑益气汤（见第十六节）
十味香薷饮（见第十六节）
败毒散（出自《活人书》）
羌活 独活 前胡 柴胡 川芎 枳壳 白茯苓 桔梗 人参（以上各一两） 甘草（半两）
将上述药物研成细末，每次服用二钱。用水一盏，加入生姜两片，煎至七分，温服。也可以用沸水冲服。
治疗伤寒温疫，风湿引起的头晕目眩，肢体拘挛蜷缩，风痰导致的头痛目眩，四肢疼痛，憎恶寒冷且高热，项部僵硬且眼睛疼痛，以及老人、小儿都可以服用。或者在瘴气烟雾之地，或者瘟疫流行之时，或者胸中多有风痰，或者居住在低洼潮湿之处导致脚弱无力，这种药都是不可缺少的。每天服用二到三次，以见效为度。如果烦躁发热、口干，可加入黄芩。
和剂五积散 治疗感冒寒邪，头痛身痛，项背部拘急不舒，恶寒呕吐，或者腹痛。又治疗伤寒发热，头痛怕风，不论内伤生冷食物，还是外感风寒，以及寒湿邪气客居于经络，导致腰脚疼痛，以及妇女月经不调，或者难产，均可治疗。
白芷 茯苓 半夏（用汤洗七次） 当归 川芎 甘草（炙烤） 肉桂 芍药（各三两） 枳壳（去掉瓤，麸皮炒） 麻黄（去掉节和根） 陈皮（去掉白色部分，各六两） 桔梗（去掉芦头，十二两） 浓朴（去掉粗皮，姜汁制） 干姜（各四两） 苍术（用淘米水浸泡，去皮，二十四两）
将上述药物切碎，每次服用四钱。用水一盏，加入生姜三片，葱白三根，煎至七分，热服。受寒重者用煨姜，兼有气滞者加吴茱萸。妇女用于调经催产，加艾叶和醋。
Wind pathogen invading the Wei (Defensive) level presents with a floating and moderate pulse accompanied by sweating. Cold pathogen invading the Ying (Nutritive) level presents with a floating and tight pulse without sweating.
Wind is a Yang pathogen, and Wei Qi (Defensive Qi) belongs to Yang Qi. Wind's nature causes porosity in the interstices, leading to the floating and hyperactivity of Wei Yang. Cold is a Yin pathogen, and Ying Blood belongs to Yin Blood. Cold's nature causes contraction and binding, leading to the coagulation and stagnation of Ying Blood. Therefore, wind inevitably injures the Wei level, and cold inevitably injures the Ying level; this is due to the principle that similar entities resonate and manifest similarly. Porosity and hyperactivity naturally result in sweating and a moderate pulse. (This corresponds to Zhang Zhongjing's Guizhi Tang syndrome.) Contraction and stagnation naturally result in no sweating and a tight pulse. (This corresponds to Zhang Zhongjing's Mahuang Tang syndrome.)
Zhang Zhongjing's Guizhi Tang (Cinnamon Twig Decoction) (see Section 19)
Zhang Zhongjing's Mahuang Tang (Ephedra Decoction) (see Section 16)
Summerheat pathogen invading the Qi level presents with a deficient pulse and body fever. Dampness pathogen invading the Blood level presents with a slow, fine, and choppy pulse.
Summerheat is also a Yang pathogen, characterized by heat and dispersion. When it invades the Qi level, it resonates due to its similar nature. A Yang pathogen injuring Qi causes Qi to become vexed and steaming, resulting in body fever. The dispersion of Qi prevents its convergence, resulting in a deficient pulse. (Suitable formulas include Qing Shu Yi Qi Tang [Clear Summerheat and Boost Qi Decoction] and Jia Wei Xiang Ru Yin [Modified Elsholtzia Drink].) Dampness is water-dampness, which is close in nature to blood; injuring the Blood level resonates due to similar nature. A slow, fine, and choppy pulse is the manifestation of dampness flowing, spreading, and adhering. (Suitable formulas include Baidu San [Rescue from Disaster Powder] and Heji Wuji San [Formulary Five Accumulations Powder].)
Qing Shu Yi Qi Tang (Clear Summerheat and Boost Qi Decoction) (see Section 16)
Shi Wei Xiang Ru Yin (Ten-Ingredient Elsholtzia Drink) (see Section 16)
Baidu San (Rescue from Disaster Powder) (from *Huo Ren Shu*)
Qianghuo (Notopterygii Rhizoma et Radix), Duhuo (Angelicae Pubescentis Radix), Qianhu (Peucedani Radix), Chaihu (Bupleuri Radix), Xiong (Chuanxiong Rhizoma), Zhike (Aurantii Fructus), Baifuling (Poria), Jiegeng (Platycodonis Radix), Renshen (Ginseng Radix et Rhizoma) (each 1 liang), Gancao (Licorice Radix et Rhizoma) (0.5 liang).
Grind into a fine powder. Take 2 qian per dose. Add 2 slices of fresh ginger to 1 cup of water, decoct until reduced to 0.7 cup, and take warm. Alternatively, it can be taken by pouring boiling water over the powder.
Indicated for Shanghan (Cold Damage) and Wenyi (Plague Toxins), wind-dampness causing dizziness, limb spasms and curling, wind-phlegm causing headache and dizziness, limb pain, aversion to cold with high fever, neck stiffness and eye pain. It is suitable for the elderly and children. It is indispensable in areas with miasma smoke, during plague epidemics, for those with much wind-phlegm in the chest, or for those living in low, damp places suffering from weak legs. Take 2–3 times daily, adjusting dosage according to efficacy. For vexing heat and dry mouth, add Huangqin (Scutellariae Radix).
Heji Wuji San (Formulary Five Accumulations Powder) Indicated for cold pathogen invasion causing headache and body pain, neck and back stiffness, aversion to cold and vomiting, or abdominal pain. Also indicated for Shanghan fever, headache, and aversion to wind, regardless of internal injury from raw/cold food or external contraction of wind-cold, as well as cold-dampness lodging in collaterals causing waist and leg pain, irregular menstruation in women, or difficult labor.
Baizhi (Angelicae Dahuricae Radix), Fuling (Poria), Banxia (Pinelliae Rhizoma) (washed seven times with decoction), Danggui (Angelicae Sinensis Radix), Xiong (Chuanxiong Rhizoma), Gancao (Licorice Radix et Rhizoma) (honey-fried), Rougui (Cinnamomi Cortex), Shaoyao (Paeoniae Radix Alba) (each 3 liang), Zhike (Aurantii Fructus) (pith removed, bran-fried), Mahuang (Ephedrae Herba) (nodes and roots removed), Chenpi (Citri Reticulatae Pericarpium) (albedo removed, each 6 liang), Jiegeng (Platycodonis Radix) (radicle removed, 12 liang), Houpo (Magnoliae Officinalis Cortex) (coarse bark removed, ginger-processed), Ganjiang (Zingiberis Rhizoma) (each 4 liang), Cangzhu (Atractylodis Rhizoma) (soaked in rice water, skin removed, 24 liang).
Cut into small pieces. Take 4 qian per dose. Add 3 slices of fresh ginger and 3 stalks of scallion white to 1 cup of water, decoct until reduced to 0.7 cup, and take hot. For severe cold exposure, use Wei Jiang (Prepared Ginger); for qi stagnation, add Zhuyu (Evodiae Fructus). For women's menstrual regulation and inducing labor, add Aiye (Artemisiae Argyi Folium) and vinegar.