A series of aminoresorcinols and related compounds were tested for rat intestinal alpha-glucosidase inhibition and these results suggested that the 2-aminoresorcinol moiety of 6-amino-5,7-dihydroxyflavone (2) is important to exert the intestinal alpha-glucosidase inhibitory activity and 2-aminoresorcinol (4), itself, is a potent alpha-glucosidase inhibitor and inhibited sucrose-hydrolyzing activity of rat intestinal alpha-glucosidase uncompetitively.