Da Chaihu Tang and Xiao Chaihu Tang differ in their composition, efficacy and main treatment conditions. Xiao Chaihu Tang is composed of several medicines: Chaihu, Scutellariae, Ginseng, Radix et Rhizoma Glycyrrhizae, Semixia, Ginger and Jujubae, which have the efficacy of conciliating the Shao-Yang (treating exogenous heat illnesses in which the evil is between the half-expression and half-lipperation). 1. Xiao Chaihu Tang is mainly used for treating typhoid fever with Shaoyang (one of the six meridians of typhoid fever, which is between the surface and the inside of the body), which is characterized by cold and heat, bitter fullness in the chest (distension and discomfort in front and at the sides of the chest), silence, lack of desire to eat or drink, upset and nausea, bitter taste in the mouth and dry throat, dizziness, etc. It can also be used to treat women whose heat has entered the bloodstream. It can also be used to treat women with heat entering the blood chamber, menstrual bleeding, cold and fever attacks, or malaria and jaundice with typhoid fever and shaoyang symptoms. 2. Da Chai Hu Tang is mainly composed of Chai Hu, Scutellaria baicalensis, Paeoniae alba, Semixia, Citrus aurantium, Rhubarb, Jujubae and Ginger, which has the effect of reconciling the Shaoyang and catharticizing the heat knot, and is mainly used for the treatment of Shaoyang-Yangming Syndromes with symptoms such as cold and heat exchanges, bitter and fullness in the chest, more than one vomiting, depression and slight vexation, fullness of pain under the heart or plumping under the heart (which refers to the distension of the stomach and the discomfort of the stomach), constipation, or discharging with heat. The main difference between these two formulas is as mentioned above, if the patient has physical discomfort and needs to be regulated, it is recommended to go to a regular Chinese medicine hospital, and be prescribed Chinese medicine by a professional doctor, and not to blindly use the medicine on your own.