To search for antiinflammtory 19alpha-hydroxyursane-type triterpenoids, the MeOH extract of the roots of Rosa rugosa (Rosaceae) was fractionated. The active fraction of the EtOAc extract was hydrolyzed in alkaline solution to give a hydrolyzed fraction. Both extracts showed antiinflammatory/antinociceptive action in acetic acid-induced writhing and hot plate testing and in a carrageenan-induced paw edema model in mice and rats. Repeated chromatography of the EtOAc extract on both silica gel and octadecylsilane columns led to the isolation of kaji-ichigoside F1 (1, euscaphic acid 28-O-glucoside) and rosamultin (2, tormentic acid 28-O-glucoside). The hydrolyzed fraction was also subjected to silica gel column and octadecylsilane column chromatography to produce euscaphic acid (3) and tormentic acid (4). The potencies were observed in the following order: 4>3>2>1. These results suggest that 19alpha-hydroxyursane-type triterpenoids are responsible for the antiinflammatory/antinociceptive action of R. rugosa roots.