Cyanidin-3-glucoside (C3G), an anthocyanin, is one of the most widespread dietary flavonoids. We investigated the effects of C3G in PMA/ionomycin (PI)-induced RBL-2H3 cells. C3G inhibited the production of IL-4 and IL-13 and also decreased the level of mRNA in a dose-dependent manner. Furthermore, western blot analysis implied that C3G down-regulated the protein level of c-Jun, NF-ATc1 and NF-${kappa}B$ but not c-Fos. Taken together, we suggest that C3G may have suppressive effects on Th2 cytokines and will be studied further to develop as functional foods that help alleviate allergy symptoms.