The Xiao Chai Hu Tang is specified in ”Shang Han Lun”, which is the main formula for the treatment of Shao Yang disease. It has wide applications. At present, it is used in cold, fever and hepatitis. The purpose is to anti-virus. The other applications nearly cover the internal medicine, surgery, gynecology, pediatrics, facial medicine, and neurology department etc., such as the treatment of bronchitis, heat in blood cavity, immunity unbalance, cancer, constipation etc. Please refer to the text for the detail description.