Scopolefin exhibited an immediate and dose-dependent hypour-icemic effect after intraperitoneal administration (50, 100, 200mg/kg) in hyperuricemic mice induced by potassium oxo-nate; however, it did not affect the serum uric acid level in nor-mal mice at the tested doses. For exploring the involved mecha-nisms of action of scopoletin, potential inhibitory effects on xan-thine oxidase and possible uricosuric effects were investigated.Scopolefin (50, 100, 200mg/kg) significantly inhibited the activ-ity of xanthine oxidase in liver homogenates of hyperuricemicmice although it only showed a relatively weak, albeit competi-tive-type, inhibition of xanthine oxidase in a commercial assay.Furthermore, a potent uricosuric effect of scopoletin (100, 200mg/kg) was ascertained. These results demonstrated for thefirst time that scopoletin exhibits, hypouricemic activitiesthrough decreasing uric acid production and as well as a uricosu-tic mechanism.