Purine or triazolopurine compounds are disclosed represented by formula (I) or (II): ##STR1## wherein R.sup.1 and R.sup.4 represent each hydrogen, halogeno, hydroxy, mercapto, or amino; R.sup.2 represents alkyl or aryl; and R.sup.3 and R.sup.5 represent each hydrogen, alkyl, or aryl; and pharmaceutical compositions comprising these compounds as xanthine oxidase inhibitors, remedies for hyperuricemia, or remedies or preventive agents for gout.