IT IS FLUOROPYRIMIDINE DERIVATIVE AND ORAL PRODRUG OF THE ANTINEOPLASTIC DRUG 5-FLUOROURACIL WITH ANTITUMOR ACTIVITY. DOXIFLURIDINE, DESIGNATED TO CIRCUMVENT THE RAPID DEGRADATION OF 5-FLUOROURIDINE BY DIHYDROXYPYRIMIDINE DEHYDROGENASE IN THE GUT WALL, IS CONVERTED INTO 5-FLUOROURIDINE IN THE PRESENCE OF PYRIMIDINE NUCLEOSIDE PHOSPHORYLASE.