Objectives : Through the study on the complex efficacy of Sosihotang(小柴胡湯), it would be expected to comprehend the concept of diseases and syndromes that will be treated and principle of composing formula. Methods : It has been done to compare and analyse provisions of Shanghanlun related with Sosihotang(小柴胡湯). Results : Sosihotang(小柴胡湯) is fit to treat symptoms based on diseases having half exterior and half interior, deficiency and excess syndromes, because it is well-composed to focus on Soyangbyeong(少陽病) and Sosihotang(小柴胡湯) syndrome caused from lose of homeostasis in human body. Conclusions : Sosihotang(小柴胡湯) is one of the multipurpose formula that can be used to treat the syndromes and diseases of exterior and interionr(表裏), cold and heat(寒熱), deficiency and excess(虛實). Therefore it is necessary to research and develop the formula with the type.