The effects of high pressure treatment on the IgE-specific binding activity and structure of bovine gamma globulin (BGG), a beef allergen, was investigated in this study. We also investigated the allergenicity of pressurized BGG. We found that the IgE-specific binding activity and allergenicity of BGG were decreased by high pressure treatment. Almost no significant changes in secondary structure were observed for pressurized BGG, but changes in the tertiary structure were seen. Therefore, decreases in the IgE-specific binding activity and the allergenicity of pressurized BGG are probably due to changes in the tertiary structure caused by pressurization.