In Japan, two patients who had been primary sensitized to hydrolyzed wheat protein (HWP) present in facial soap and subsequently experienced wheat-dependent exercise-induced anaphylaxis (WDEIA) after the ingestion of normal wheat products were reported in 2009 as first cases. Since that report, more than 1900 patients with such an allergy have been reported (through June 20, 2013) from various institutes all around Japan. Importantly, the majority of the patients used the same facial soap (Cha no Shizuku(®)) containing acid-hydrolyzed wheat protein (acid-HWP). The commercial acid-HWP contained in the facial soap (Glupearl 19S(®), average molecular weight of 30-50 kDa) was produced from gluten after partial hydrolysis with hydrogen chloride at 95℃ for 40 minutes. In this presentation, I would like to summarize the mechanism of the induction of immediate hypersensitivity by HWP which has been reported by us and other European groups.