Objective : This study was designed to investigate the effects of Curcuma longa Rhizoma(CLR) on asthma. Methods : Detecting splenocyte proliferation rates, cytokines and antigen specific antibody isotypes in bronchoalveolar lavage fluid (BALF). In addition, the present author I also investigated changes in spleen and histopathological changes of lung tissues. Results : Oral administration of CLR lowered spleen weight and splenocyte proliferation rates. In addition, levels of IL-4, IL-17A and Granulocyte/Macrophage Colony-Stimulating Factor(GM-CSF), Th2 driven cytokines, were lowered respectively and IFN-g, and Th1 driven cytokine, were elevated by CLR. Levels of Ovalbumin(OVA) specific IgE and IgGl in BALF were also lowered by oral administration of CLR too. Conclusion : CLR is useful to treat patients with asthma and the mechanisms are related to the in suppression of Th2 skewing reactions.