The morphological and histochemical observation of the lectin binding to intestine in vivo or in vitro was investigated. Our finding demonstrates the validity of semi-quantitative estimates of lectin binding to mouse intestine. The fluorescence patterns obtained after treatment of intestine sections with FITC-conjugated lectin revealed that Kintoki bean lectin (KBL) and Taro tuber lectin (TTL) were localized on the cell membrane, especially the top and upper sites of the villi and showed that KBL was more strongly located than TTL under various conditions. In the reverted intestine of mice fed lectin, the villi were considerably disordered and conspicuously disrupted.