In enzymology, a dihydrouracil oxidase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are dihydrouracil and oxygen. Its products are uracil and hydrogen peroxide.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with oxygen as acceptor. The systematic name of this enzyme class is 5,6-dihydrouracil:oxygen oxidoreductase. It uses the cofactor, flavin mononucleotide.