A new monoterpene glycoside (1) isolated from the aerial part of Sibirae angustata RCHD. (Rosaceae) was found to be 1-O-beta-D-glucopyranosyl-geraniol-5,10-olide and named as sibiskoside. Acute toxicity study revealed that oral administration of 1 (2.5 g/kg body weight) to mice resulted in no death and no evidence of abnormalities in internal organs. Its oral administration to the mice reared with high-fat diet resulted in weight-loss, which was also reflected in serum triglyceride and sugar level, and the weight of abdominal fat. Sibiskoside could be considered to be an active ingredient of Liucha for exerting weight-loss effect in a drink of S. angustata.