The present study was aimed at investigating the hypouricemic and xanthine oxidase inhibitoryactivities of the various fractions of the hydromethanolic extract of the leaves of Coccinia grandis L.Voigt (Cucurbitaceae). The leaves of this species was used in traditional medicinal system for thetreatment of gout, rheumatism, jaundice, bronchitis, fever, skin eruptions, wounds, etc. Thedegree of xanthine oxidase inhibition was determined in vitro by measuring the increase inabsorbance at 295 nm associated with uric acid formation. Among the fractions tested, thechloroform fraction exhibited highest potency (IC50 17.8 µg/ml). This was followed by the pet-ether (IC50 29.7 µg/ml), ethyl acetate (IC50 41.2 µg/ml) and residual (IC50 47 µg/ml) fractions. TheIC50 value of allopurinol was 6.1 µg/ml. In addition, the hypouricemic and hepatic xanthineoxidase (XO)/xanthine dehydrogenase (XDH) inhibitory activities of the fractions were examinedin vivo using oxonate (280 mg/kg, i.p.) induced hyperuricemic mice. At a dose of 200 mg/kgorally for 7 days, the pet-ether, chloroform and ethyl acetate fractions produced a significant(P < 0.01) reduction in serum urate level and also inhibited hepatic XO/XDH activities whencompared to hyperuricemic mice. These inhibitory effects were weaker than that observed for thestandard drug, allopurinol (10 mg/kg, p.o.). Lineweaver-Burk analysis of the enzyme kineticsindicated that the mode of inhibition was of a mixed type. These results suggest that the use ofCoccinia grandis leaves for the treatment of gout could be attributed to its XO inhibitory activity.