Furfural is an organic compound derived from a variety of agricultural byproducts, including corncobs, oat, wheat bran, and sawdust. The name furfural comes from the Latin word furfur, meaning bran, referring to its usual source.

Furfural is an aromatic aldehyde, with the ring structure shown at right. Its chemical formula is OC4H3CHO. It is a colorless oily liquid with the odor of almonds, but upon exposure to air samples quickly becomes yellow.