The retarding activity of 6-O-dodecanoyl-d-allose against rice growth was higher than that of the octanoate and the decanoate. The activities of 6-O-dodecanoyl-d-glucose, -d-mannose, and -d-galactose against rice seedlings were examined. 6-O-Dodecanoyl-d-allose exhibited the highest activity, suggesting the importance of the α-axial hydroxy group at C-3 of d-allose.