Oxypurinol has been used as a xanthine oxidase inhibitor, to evaluate its effects on hepatocellular carcinoma cell proliferation. It has also been used as a xanthine inhibitor to elucidate its contribution in the induction of hpv16 late gene expression. Oxypurinol, an allopurinol metabolite, is used as an inhibitor to study the specificity and kinetics of of xanthine oxidase(s). Oxypurinol is also used as an anti-inflammatory agent via inhibition of xanthine oxidase.