Curcumin, a dietary pigment responsible for the yellow color of curry, has been used for the treatment of inflammatory diseases and exhibits a variety of pharmacological effects such as anti-inflammatory, anti-tumor, anti-oxidant, and anti-viral activity. However, it has not been determined whether the effect of curcumin on the production of cytokine affects eosinophil functions and IgE synthesis. In the present study, we examined the effect of curcumin on the production of interleukin (IL)-2, IL-5, granulocyte macrophage-colony stimulating factor (GM-CSF), and IL-4 by lymphocytes from atopic asthmatics in response to house dust mites (Dermatophagoides farinea: Df) in order to clarify a potential application for allergic diseases. Curcumin inhibited Df-induced lymphocyte proliferation and production of IL-2. Exogenous IL-2 reconstituted the proliferative responsiveness of lymphocytes to Df in the presence of curcumin. Furthermore, curcumin inhibited IL-5, GM-CSF, and IL-4 production in a concentration-dependent manner. These results indicate that curcumin may have a potential effect on controlling allergic diseases through inhibiting the production of cytokines affecting eosinophil function and IgE synthesis.