Exogenous diseases are characterized by the struggle between the righteous and the evil, which leads to fever.
The Chinese herbal medicines for treating fever can be divided into two categories: those that release the exterior and those that clear heat.
Herbs that release the exterior can be classified based on their properties into three types: warming (辛温, xin wen), cooling (辛凉, xin liang), and neutral (辛平, xin ping) releasing herbs.
Warming releasing herbs include Ma Huang (Ephedra), Gui Zhi (Cinnamon Twig), Qiang Huo (Notopterygium), Zi Su Ye (Perilla Leaf), Huo Xiang (Agastache), Jing Jie (Schizonepeta), Fang Feng (Siler), and Sheng Jiang (Ginger). This category is used when there is no sore throat or dryness of the mouth and tongue. If there is throat pain without swelling, accompanied by nasal congestion and clear nasal discharge, and a cough with thin phlegm, these herbs can still be used. Warming releasing herbs can also be used for wind-heat exterior syndrome, such as Ma Huang combined with Shi Gao (Gypsum).
Cooling releasing herbs include Shi Gao (Gypsum), Bo He (Peppermint), Chai Hu (Bupleurum), Sheng Ma (Cimicifuga), Ge Gen (Kudzu Root), Mulberry Leaf (Sang Ye), and Ju Hua (Chrysanthemum). Some of these herbs are used when there is sore throat and dryness of the mouth and tongue.
Jing Jie and Bo He are considered neutral and can be used for both wind-cold and wind-heat conditions, thus they can also be classified as neutral releasing herbs.
Herbs that release the exterior typically induce sweating, which helps to reduce fever. If sweating does not occur, or if sweating occurs but the fever does not subside, there must be another underlying cause.
If there is no sweating and the fever persists, it indicates a strong disease condition, or a deficiency of Qi or fluids that prevents sweating.
If sweating occurs but the fever does not subside, or if the fever subsides temporarily and then returns, this indicates that the disease condition has not significantly decreased. Once the effect of the releasing herbs wears off, the fever may return. Qi deficiency or fluid deficiency can also lead to sweating without resolution of fever.
Additionally, if there is simultaneous sweating and fever, this indicates a deficiency of righteous Qi.
Another condition is characterized by no sweating, persistent fever, and fever that recurs after subsiding. This mechanism indicates that dampness is obstructing the body. When dampness obstructs, there will be body aches. Although Fang Feng and Qiang Huo can release the exterior and dispel dampness, they are only suitable for wind-cold with dampness. If there is wind-heat with dampness, accompanied by body aches, sore throat, and dryness of the mouth and tongue, Qiang Huo should not be used as it may further damage fluids. The most suitable herbs for this condition are Mu Guo (Papaya), followed by Yi Yi Ren (Job’s Tears).
As for clearing heat to reduce fever, the most representative formulas are Bai Hu Tang (White Tiger Decoction) (composed of Shi Gao (Gypsum), Jing Mi (Geng Rice), Gan Cao (Licorice), and Zhi Mu (Anemarrhena)) and Liang Ge San (Cool the Diaphragm Powder) (composed of Bo He (Peppermint), Lian Qiao (Forsythia), Gan Cao (Licorice), Zhi Zi (Gardenia), Huang Qin (Scutellaria), Da Huang (Rhubarb), Mang Xiao (Mirabilite), and Zhu Ye (Bamboo Leaf)). These treatments and formulas must be used only for pure heat syndromes, where symptoms include dryness of the mouth and tongue, thirst that is unrelieved by drinking, irritability, insomnia, and a burning sensation in the nasal cavity. If there is a mixture of cold and heat, or if there is Qi deficiency, these should not be used.
The formula I propose, Hua Shi Tou Re Tang (Transform Dampness and Clear Heat Decoction), is suitable for fever due to damp-heat syndrome, using sore throat and body aches as the criteria for use. Once the fever subsides, it is no longer necessary to continue using it. If there are also symptoms of dry and itchy throat with cough, adjustments to the herbs should be made according to the symptoms, and one should not rigidly adhere to a single formula or method.