【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。
【歌诀】外感与内伤都会引起发热，阳虚和阴虚导致的发热各有其理论依据。火郁引起的发热则有所不同，烦热和骨蒸（一种自觉骨中透热的症状）需要仔细辨别。
【论述】如果是外感引起的发热，人迎脉（位于颈部两侧，反映体表邪气盛衰的脉位）搏动盛大，伴有表证，表现为如羽毛覆盖般的轻微发热（翕翕发热），或像热气熏蒸样的发热（然热/濈然热），明确知道病邪在体表，只需使用发汗法治疗即可。如果是内伤饮食不当引起的发热，气口脉（位于手腕桡动脉处，反映脾胃及体内状况的脉位）紧而盛大，伴有胸脘胀满、嗳气，表现为像蒸汽升腾样的发热（蒸蒸然热），明确知道病邪在体内，只需使用消食导滞法治疗，发热自然消退。如果是因劳累过度导致的气血内伤引起的发热，脉象虚弱无力，四肢倦怠乏力，不恶寒，自汗出，明确知道没有表证也没有里实证，属于虚热，只需使用补益滋养法治疗，发热就会退去。阳虚引起的发热，表现为不能耐受风寒，自汗出，脉象大而无力。阴虚引起的发热，脉象数而无力，通常在下午发作。阴分郁热引起的发热，表现为手心脚心发热，肌肤表面热度不明显，热势不能向外舒展发散。烦热，即虚性烦躁伴有的热感。劳热，热感深入骨髓，即骨蒸热。如果按照上述方法观察，表证与里证、虚证与实证的显著区别就清楚了，临证时应当明辨。
外感发热
外感寒邪，无汗且恶寒，用麻黄汤。感受风邪，有汗且恶风，用桂枝汤。突然感受风寒，用参苏饮。
麻黄汤
麻黄（君药） 桂枝（臣药） 甘草（佐使药） 杏仁（臣药）
以上药材，用生姜三片，带须的葱白三个，水两碗，煎煮至一碗，服用。
桂枝汤（方剂见“恶寒”条目下。）
参苏饮（方剂见“伤风”条目下。）
内伤发热
内伤饮食引起的发热，用柴胡二陈汤加枳实、山楂、神曲。因劳累过度内伤引起的发热，用补中益气汤，兼夹外邪者，在本方基础上加羌活。房事过度内伤引起的发热，用前方（指补中益气汤）加知母、黄柏。饮酒过量内伤引起的发热，用葛花解酲汤。
柴胡二陈汤
即二陈汤加入柴胡。（方剂见“痰证”条目下。）
补中益气汤（方剂见“内伤”条目下。）
葛花解酲汤（方剂见“内伤”条目下。）
阴阳虚热（附郁热、劳热）
阴虚发热，用四物汤加知母、黄芩、柴胡。若兼气虚再加人参、[此处原文缺字，通常指黄芪]。阳虚发热，用小建中汤。
郁热，用升阳散火汤。
劳热，发生于阴分，多表现为骨蒸内热，用逍遥散、地骨皮散。
四物汤（方剂见“血证”条目下。）
小建中汤（方剂见“恶寒”条目下。）
升阳散火汤（方剂见“火证”条目下。）
逍遥散（方剂见“火证”条目下。）
地骨皮散
治疗虚劳引起的发热咳嗽。
地骨皮（君药） 柴胡（臣药） 知母（臣药） 人参（臣药） 茯苓（臣药） 甘草（臣药） 半夏（佐药，此一味药性燥烈，恐怕难以使用，不如用贝母代替。）
以上药材切碎，一剂药，用水两碗，煎煮至一碗，加入生姜自然汁五匙，稍加热后服用。
[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.