Evidence has been accumulating to suggest that disulfide bonding is one of the key causes of allergenicity. Recently we developed the "disulfide proteome", a technique for the comprehensive analysis of disulfide bonding of proteins. We applied this new technique to the rice seed's salt-soluble fraction, which has long been known to be allergenic. Most proteins in the fraction, including alpha-amylase/trypsin inhibitor, alpha-globulin, and glutelin fragments, have formed intramolecular disulfide bonds. Also, unknown proteins, including one sharing similarities with known allergens, had disulfide bonds, from which we can infer possible allergenicity. This is a preliminary study to screen allergens from the basis of disulfide bonding.