The effect of blueberry (Vaccinium angustifolium) root methanolic extract (BRM) on the A23187 plus phorbol myristate acetate (PMA)-induced degranulation in human basophilic KU812F cells was investigated. The total phenolic content (TPC) was $170{pm}1.9$ mg gallic acid equivalents (GAE)/g BRM. BRM reduced levels of histamine and $eta$-hexosaminidase released from stimulated KU812F cells. Intracellular calcium concentration ([$Ca^{2+}$]i) were determined by spectrofluorometric analysis using Fura 2-AM was found to be reduced by BRM with dosedependent manner. Moreover, Western blot analysis revealed that protein kinase C (PKC) translocation was inhibited by BRM with dose-dependent manner. These results indicated that BRM inhibited histamine and $eta$-hexosaminidase through the suppression of $Ca^{2+}$ influx and PKC translocation. Therefore, we suggest that BRM is potent inhibitor of degranulation in mast cells and basophils, and may be useful in preventing the allergic reactions.