【歌】外感内伤皆发热，阳虚阴虚良有说。火郁发热自不同，烦热骨蒸须审别。
【论】夫外感发热，则人迎脉盛，有表证，翕翕发热， 然热，明知其热在外也，汗之而已。内伤饮
食发热者，气口脉紧盛，胸满噫气，蒸蒸然热，明知其热在里也，消导则自已。劳役内伤发热者，脉虚而弱，
四肢怠惰无力，不恶寒，自汗出，明知其无表里证，虚热也，补养则热退。阳虚发热者，不任风寒，自汗，脉
大而无力。阴虚发热者，脉数而无力，作于下午。阴分郁热者，手足心热，肌肤不甚热，热不伸越也。烦热者，
即虚烦躁热也。劳热者，其热者骨，骨蒸热是也。若此看，表里虚实之迥别，临证当明辨也。
外感发热
外感寒邪，无汗恶寒，麻黄汤。感风邪，有汗恶风，桂枝汤。时暴感风寒，参苏饮。
麻黄汤
麻黄（上） 桂枝（中） 甘草（下） 杏仁（中）
上，用姜三片，葱白头连须三枚，水二盏，煎一盏服。
桂枝汤（方见恶寒条。）
参苏饮（方见伤风条。）
内伤发热
内伤饮食发热者，柴胡二陈汤加枳实、山楂，神曲。劳倦内伤发热者，补中益气汤，挟外邪者，本方加
羌活。房劳
内伤发热者，前方加知母、黄柏。饮酒内伤发热者，葛花解酲汤。
柴胡二陈汤
即二陈汤加柴胡。（方见痰证条。）
补中益气汤（方见内伤条。）
葛花解酲汤（方见内伤条。）
阴阳虚热（附郁热、劳热）
阴虚发热者，四物汤加知母、黄芩、柴胡。气虚再加参、 。阳虚发热者，小建中汤。
郁热者，升阳散火汤。
劳热者，作于阴分，多骨蒸内热，逍遥散、地骨皮散。
四物汤（方见血证条。）
小建中汤（方见恶寒条。）
升阳散火汤（方见火证条。）
逍遥散（方见火证条。）
地骨皮散
治虚劳发热咳嗽。
地骨皮（上） 柴胡（中） 知母（中） 人参（中） 茯苓（中） 甘草（中） 半夏（下，此一味
性燥，恐难用，不若以贝母代之。）
上锉，一剂，水二盏，煎至一盏，加生姜自然汁五匙，稍热服。
[Verse] Both external contraction and internal injury can cause fever; there are valid theories distinguishing those caused by Yang deficiency from those by Yin deficiency. Fever due to Fire stagnation is different; one must carefully distinguish between vexatious heat (vexation accompanied by heat sensation) and bone-steaming fever (a subjective sensation of heat penetrating from the bones).
[Discussion] When fever is caused by external contraction, the Renying pulse (pulse at the neck reflecting exterior pathogenic factors) is vigorous, accompanied by exterior syndrome manifestations such as "xi xi" fever (mild fever resembling feathers covering the body) or "ji ran" fever (fever resembling steaming), clearly indicating that the pathogen is in the exterior; sweating therapy should be applied. When fever is caused by internal injury from diet, the Qikou pulse (pulse at the wrist reflecting spleen/stomach condition) is tight and vigorous, accompanied by chest fullness and belching, with a feeling of "zheng zheng" fever (fever rising like steam), clearly indicating that the pathogen is in the interior; resolving food stagnation and promoting digestion will resolve the fever spontaneously. When fever is caused by internal injury from overwork, the pulse is deficient and weak, limbs are lethargic and powerless, there is no aversion to cold, and spontaneous sweating occurs; clearly indicating neither exterior nor interior excess syndromes, this is deficiency heat, which will subside with tonification and nourishment. Fever due to Yang deficiency presents as intolerance to wind and cold, spontaneous sweating, and a large but forceless pulse. Fever due to Yin deficiency presents as a rapid but forceless pulse, occurring typically in the afternoon. Heat due to Yin branch stagnation presents as heat in the palms and soles, with minimal surface skin heat and an inability for the heat to expand outward. Vexatious heat refers to deficiency-related restlessness accompanied by heat. Labor fever refers to heat penetrating the bones, also known as bone-steaming fever. By observing according to these criteria, the distinct differences between exterior/interior and deficiency/excess syndromes become clear, requiring precise differentiation during clinical practice.
External Contraction Fever
For external contraction of Cold pathogen with no sweating and aversion to cold, use Mahuang Tang (Ephedra Decoction). For contraction of Wind pathogen with sweating and aversion to wind, use Guizhi Tang (Cinnamon Twig Decoction). For sudden contraction of Wind-Cold, use Shen Su Yin (Ginseng and Perilla Drink).
Mahuang Tang (Ephedra Decoction)
Ephedrae Herba (Mahuang, 麻黄) [Chief Ingredient], Cinnamomi Ramulus (Guizhi, 桂枝) [Deputy Ingredient], Glycyrrhizae Radix et Rhizoma (Gancao, 甘草) [Assistant/Envoy Ingredient], Armeniacae Semen Amarum (Xingren, 杏仁) [Deputy Ingredient].
Take the above ingredients, add three slices of Zingiberis Rhizoma Recens (Fresh Ginger, Shengjiang), three scallion whites (Allii Fistulosi Bulbus, Congbai) with roots, two cups of water, decoct to one cup, and take orally.
Guizhi Tang (Cinnamon Twig Decoction) (See formula under "Aversion to Cold").
Shen Su Yin (Ginseng and Perilla Drink) (See formula under "Wind Injury").
Internal Injury Fever
For fever due to internal injury from diet, use Chaihu Erchen Tang (Bupleurum and Two-Chen Decoction) plus Fructus Aurantii Immaturus (Zhishi, 枳实), Crataegi Fructus (Shanzha, 山楂), and Massas Medicata Fermentata (Shenqu, 神曲). For fever due to internal injury from fatigue, use Buzhong Yiqi Tang (Tonify the Middle and Augment the Qi Decoction); if complicated by external pathogens, add Radix Notopterygii (Qianghuo, 羌活) to this formula. For fever due to internal injury from sexual exhaustion, add Radix Anemarrhenae (Zhimu, 知母) and Cortex Phellodendri (Huangbai, 黄柏) to the aforementioned formula. For fever due to internal injury from alcohol, use Ge Hua Jie Cheng Tang (Kudzu Flower Decoction to Resolve Intoxication).
Chaihu Erchen Tang (Bupleurum and Two-Chen Decoction)
This is Erchen Tang (Two-Chen Decoction) plus Radix Bupleuri (Chaihu, 柴胡). (See formula under "Phlegm Syndrome").
Buzhong Yiqi Tang (Tonify the Middle and Augment the Qi Decoction) (See formula under "Internal Injury").
Ge Hua Jie Cheng Tang (Kudzu Flower Decoction to Resolve Intoxication) (See formula under "Internal Injury").
Yin-Yang Deficiency Heat (Including Stagnation Heat and Labor Fever)
For Yin deficiency fever, use Siwu Tang (Four Substances Decoction) plus Radix Anemarrhenae (Zhimu, 知母), Radix Scutellariae (Huangqin, 黄芩), and Radix Bupleuri (Chaihu, 柴胡). If Qi deficiency is also present, add Radix Ginseng (Renshen, 人参) and [text missing, typically Atractylodis Macrocephalae Rhizoma or Astragali Radix]. For Yang deficiency fever, use Xiaojianzhong Tang (Minor Construct the Middle Decoction).
For stagnation heat, use Shengyang Sanhuo Tang (Raise Yang and Disperse Fire Decoction).
For labor fever, which occurs in the Yin branches and often presents as bone-steaming internal heat, use Xiaoyao San (Free and Easy Wanderer Powder) and Digupi San (Lycium Bark Powder).
Siwu Tang (Four Substances Decoction) (See formula under "Blood Syndrome").
Xiaojianzhong Tang (Minor Construct the Middle Decoction) (See formula under "Aversion to Cold").
Shengyang Sanhuo Tang (Raise Yang and Disperse Fire Decoction) (See formula under "Fire Syndrome").
Xiaoyao San (Free and Easy Wanderer Powder) (See formula under "Fire Syndrome").
Digupi San (Lycium Bark Powder)
Treats fever and cough due to consumptive disease.
Cortex Lycii (Digupi, 地骨皮) [Chief Ingredient], Radix Bupleuri (Chaihu, 柴胡) [Deputy Ingredient], Radix Anemarrhenae (Zhimu, 知母) [Deputy Ingredient], Radix Ginseng (Renshen, 人参) [Deputy Ingredient], Poria (Fuling, 茯苓) [Deputy Ingredient], Glycyrrhizae Radix et Rhizoma (Gancao, 甘草) [Deputy Ingredient], Pinelliae Rhizoma (Banxia, 半夏) [Assistant Ingredient; this herb is drying and difficult to use, it is better to substitute it with Fritillariae Bulbus/Beimu, 贝母)].
Chop the above ingredients. For one dose, use two cups of water, decoct to one cup, add five spoonfuls of fresh juice extracted from Zingiberis Rhizoma Recens (Fresh Ginger, Shengjiang), warm slightly, and take orally.