It is well known that Dioscoreae Rhizoma tonifies and benefits the Spleen and Stomach, benefits the Lung and nourishes the Kidney. A major component isolated from this herb consist of dioscin, diosgenin, allantoin, starch, alanin, mucilage, choline, amylase, and glycoprotein. In this study, we aimed to measure the content of allantoin, one of major component, to determine the quality of Dioscoreae Rhizoma.