The effect of solvent fractions from brown algae (Ishige okamurae) on allergic inflammatory reactions was investigated via measuring histamine release and cytokine generation in human basophilic KU812F cells induced by calcium ionophore A23187. Moreover, polyunsaturated fatty acids (PUFAs) profiles were identied and quantied in the most active fraction. It was found that n-hexane and ethyl acetate (EtOAc) fraction at 50 ${mu}g/mL$ significantly reduce histamine release with the release rates of 24 and 20%, respectively. Likewise, the suppressive effect of n-hexane and EtOAc fraction on production as well as expression of interleukin (IL)-4 and IL-13 was determined. Notably, EtOAc fraction exhibited more effective inhibition than n-hexane in all assays. Furthermore, GC analysis revealed that EtOAc fraction contains various antiinflammatory PUFAs such as eicosapentaenoic acid, eicosatrienoic acid, linolenic acid, and ${gamma}$-linolenic acid. Collectively, EtOAc fraction from brown algae could be a potential inhibitor of allergic inflammatory reactions in basophils that is suggested to be due to PUFAs.