Background : Asthma is considered to be an inflammatory disease characterized by airway hyperresponsiveness and pulmonary eosinophilia. Production of cytokines by bronchial epithelial cells may contribute to the local accumulation of inflammatory cells in patients with bronchial asthma. In many recent studies molecular biological methods have been used to investigate the role of cytokines in pathogenesis and new therapeutic targets of asthma. Objective : We aimed to identify the effects of Sochongryong-tang on Serum IL-4, IL-5, $IFN-{gamma}$ in asthmatic patients. Material and Methods: The subjects consisted of 15 patients with asthma who had been treated with Sochongryong-tang for two weeks from February 2001 through June 2001. Sochongryong-tang is an herbal decoction which has traditionally been used as a therapeutic agent for asthma. Results : The serum IL-4 in asthmatic patients was increased significantly compared to the serum IL-4 in the normal control group. However, the serum IL-5, $IFN-{gamma}$ in asthmatic patients showed no significant difference from the serum IL-5, $IFN-{gamma}$ in the normal control group. The patients were treated with Sochongryong-tang for two weeks with no significant difference in the serum IL-4, IL-5, and $IFN-{gamma}$. Conclusion : This study shows that the serum IL-4 may be a new therapeutic target of asthma. Further long-term studies must be made in a larger number of asthmatic patients.