Formulas for clearing heat are mainly composed of medicinals for clearing heat, and bear the function of clearing heat and draining fire, cooling the blood and resolving toxicity, and are used for internal heat syndromes. Wang Ang called them, “formulas for draining fire” (泻火之剂) in the Medical Formulas Collected and Analyzed and Wu Yiluo called them the “doorway to draining fire”(泻火门) in the Practical Usage of Established Formulas and categorized them under the“clearing treatment” section of the Eight Treatment Methods.

Regarding the origin and development of formulas for clearing heat, it is indicated in Basic Questions - Great Treatise on the Essentials of Supreme Truth : “ For heat, cool it ” (热者寒之), “ for warmth, clear it ” (温者清之). This is the basis of, and principle for, the application of formulas for clearing heat. In the Discussion on Cold Damage and Essentials from the Golden Cabinet , Zhang Zhong-jing in the Eastern Han Dynasty established many formulas for clearing internal heat such as Bái Hŭ Tāng (White Tiger Decoction), Zhú Yè Shí Gāo Tāng (Lophatherum and Gypsum Decoction, 竹叶石膏汤), Zhī Zĭ Chĭ Tāng (Gardenia and Fermented Soybean Decoction, 栀子豉汤), Xiè Xīn Tāng (Heart-Draining Decoction, 泻心汤), Gé Gēn Huáng Qín Huáng Lián Tāng (Pueraria, Scutellaria, and Coptis Decoction, 葛根黄芩黄连汤), Huáng Qín Tāng (Scutellaria Decoction, 黄芩汤), and Bái Tóu Wēng Tāng (Pulsatilla Decoction, 白头翁汤), and set up the front line in syndrome differentiation and treatment of internal heat syndromes and greatly influenced the formation and development of the understanding of warm diseases. In the time between the Jin and Tang Dynasties, it was recorded in the Emergency Formulas to Keep Up One’s Sleeve ( Zhŏu Hòu Bèi Jí Fāng , 肘后备急方) by Ge Hong that hēi gāo (Black Paste, 黑膏) was used for cooling ying qi, dispersing evil and alleviating purpura; in the Essay on Formulas ( Xiăo Pĭn Fāng , 小品方), Sháo Yào Dì Huáng Tāng (Peony and Rehmannia Decoction, 芍药地黄汤) was first used for cooling the blood and dispersing stasis to treat blood retention, spontaneous external bleeding, and haematemesis, etc. This formula was given close attention and propagated by the warm disease schools; although the method of clearing ying and cooling blood was not clearly explained. Also, Chao Yuanfang listed in Discussion on the Origins of the Symptoms of Disease ( Zhū Bìng Yuán Hóu Lùn , 诸病源候论) the “ various symptoms of heat disease ” (热病诸候) “ various symptoms of warm disease ” (温病诸候), etc. In the Arcane Essentials from the Imperial Library , Wang Tao collected many formulas for clearing heat, which enriched the content of syndrome differentiation and treatment of heat diseases. During the Song, Jin, and Yuan period, Qian Yi created formulas for treating the zang-fu organ heat disease according to the different characteristics of heat in the zang-fu organs. His book, Key to Diagnosis and Treatment of Children’s Diseases ( Xiăo Ér Yào Zhèng Zhí Jué , 小儿药证直诀) discusses formulas such as Dăo Chì Săn (Red-Abducting Powder, 导赤散), Xiè Bái Săn (White-Draining Powder, 泻白散), Xiè Huáng Săn (Yellow-Draining Powder), Xiè Qīng Wán (Green-Blue-Draining Pill, 泻青丸), which improved these treatments by directing the formulas at the diseased regions in heat syndromes. Liu Wan-su who focused on research of the pathomechanisms of fireheat and excelled at applying cold and cool medicinals, not only summarized the treatment principle of heat disease, but also created formulas for clearing heat such as Shuāng Jiĕ Săn (Double Resolution Powder), Yì Yuán Săn (Origin-Boosting Powder, 益元散), and so on. Prior to the Ming and Qing Dynasties, warm disease theory attained great development with the continuous and deepening recognition of pestilence, warm disease, and seasonal disease. Scholars of warm disease represented by Ye Gui, Xue Xue, Wu Tang, Wang Shi-xiong, et al , established the method of syndrome differentiation and treatment with the core concepts centered on defensive qi, nutrient-blood, and the sanjiao . They summarized large numbers of effective formulas for clearing heat and further expanded the range of syndromes and treatments of heat disease. Cheng Guo-peng ingeniously stated in Medical Revelations the indications and applications of the clearing method, which was enlightening for later doctors for the correct application of formulas for clearing heat. After the founding of the People’s Republic of China, formulas for clearing heat achieved great advancement in both clinical and experimental study, and attained notable effects in the wide application for acute infectious diseases such as“epidemic meningitis”, “Japanese encephalitis B” epidemic haemorrhagic fever, viral hepatitis, diphtheria, bacillary dysentery and septicemia, etc. There was also significant study of formulas for clearing heat concerned with anti-infection, anti-tumor, analepsia of endothelial system, improvement of the function of phagocytes, pharmacological effects, cardiac reinforcement, fever relieving, diuresis, decreasing the blood pressure, etc. , these formulas have produced wide interest from the medical field at home and abroad with abundant prospects in their development and application.

Internal heat syndromes have a wide range with complicated changes in the pathogenic condition. According to the difference in diseased region, level, property, and aspect of internal heat syndrome, formulas for clearing heat can be divided into four types i. e. formulas for cooling heat in the qi aspect, for clearing ying and cooling blood, for clearing heat in the zang-fu organs, and for clearing deficient heat. Regarding formulas for clearing heat and resolving toxicity, they are indicated for interior burning of heattoxicity and unresolved heat in the qi aspect, so they are categorized into formulas for cooling heat in the qi aspect. v29PbEqg+6eYoTxfGs6GEUKuOYZqvzPJE9lCrucf9qdLbcRnkQnX43dCr2DXERY6