Objective : This study was designed to investigated effects of Pinelliae Rizoma (PR) on asthma Methods : Detecting antigen specific antibody isotypes, cytokines in serum and bronchoalveolar lavage fluid (BALF). In addition, the present author also investigated changes in weight of spleen and proliferation rates of splenocytes. Finally, histopathological observation of the lung tissue was also investigated. Results : Oral administration of PR lowered OVA specific IgE levels in serum, IgG1 levels in serum and BALF. PR also decreased production levels of IL-4 in BALF. In addition, total cells in BALF were decreased by oral administration of PR effectively. In histapathological observation, PR group showed downward tendency of inflammatory cell infiltration around small vessels. Conclusion : PR is useful to treat patients with asthma and the mechanisms are related in suppression of Th2 skewing reactions.