From the aqueous extract of the root of Hemerocallis longituba Miq. (Japanese name "No-kanzô"), presence of cysteic, aspartic, and glutamic acids, threonine, serine, proline, glycine, alanine, cystine, valine, methionine, alloisoleucine, isoleucine, leucine, tyrosine, and phenylalanine was identified, and r_s -4-hydroxyglutamic acid, asparagine, lysine, and arginine were isolated. As the organic components, succinic and lactic acids were isolated and identified. The residue remaining after extraction with water was extracted with methanol, and friedelin, β-sitosterol, ethyl benzoate, and β-sitosteryl p-glucoside were isolated and identified from the methanol extract.