Abstract: A pharmaceutical composition in unit dosage form adapted for topical administration to a human or non-human animal in need thereof comprising a pharmacologically effective amount of a prodrug of 5-fluorouracil having the formula: ##STR1## wherein R.sub.3 is bonded to C=O by a carbon-to-carbon bond and is a group such that the prodrug (1) has an enhanced delivery across topical membranes and (2) hydrolyzes after delivery to 5-fluorouracil.