There are many ways to add and subtract Xiao Chaihu Tang, with different efficacies, including clearing heat and regulating qi to broaden the chest, quenching thirst and generating fluids, nourishing the liver and relieving pain, inducing diuresis and tranquilizing the heart, warming the lungs and relieving coughs, and so on. Xiao Chaihu Tang is from “The Treatise on Typhoid Fever”, which is a conciliatory agent with the efficacy of conciliating shaoyang (treating exogenous fever with the evil between half-epidermal and half-lippery), and is mainly used for treating the symptoms of typhoid fever and shaoyang (one of the six meridians of the Treatise on Typhoid Fever with the location between the epidermis and the lippery). The main components of Xiao Chai Hu Tang are Chai Hu, Scutellaria baicalensis, Ginseng, Semixia, Glycyrrhiza glabra, Ginger and Jujubes. 1. Clearing heat, regulating qi and broadening the chest: if one feels tightness in the chest but does not have the symptom of vomiting, the prescription subtracts Radix et Rhizoma Pinelliae and Radix et Rhizoma Ginseng, and adds Psidium Guajava, in order to achieve the effect of clearing heat, regulating qi and broadening the chest. 2. Quenching thirst and generating fluids: if there are symptoms of thirst, the prescription subtracts Pinellia and adds Rhizoma Smallpox Powder to achieve the effect of quenching thirst and generating fluids. 3. Nourishing the liver and relieving pain: if there are symptoms of pain in the abdomen, the remedy subtracts Scutellariae Radix and adds Paeoniae Radix to nourish the liver and relieve pain. 4. Inducing diuresis and tranquilizing the heart: if one feels panicky and has the symptom of unsmooth urination, the remedy subtracts Scutellariae and adds Poria to achieve the effect of inducing diuresis and tranquilizing the heart. 5. Warming the lungs and relieving cough: if there are symptoms of cough, the prescription subtracts ginseng, jujube and ginger and adds schizandra and dried ginger to warm the lungs and relieve cough. Because of the ascending and dispersing nature of Chai Hu in Xiao Chai Hu Tang, and the dry nature of Scutellariae Radix and Semen Haematoxylinis, this formula should not be used by people with deficiency of yin and blood. Xiao Chaihu Tang originally has many methods of addition and subtraction. The addition, subtraction and customization of Chinese herbal formulas should be carried out under the guidance of traditional Chinese medicine practitioners, and should not be taken on one’s own, so as to avoid adverse reactions caused by incorrect medicines.