3-Eth-oxy-4-hydroxy-benzaldehyde.

The title compound (ethyl vanillin), C(9)H(10)O(3), an important food additive and flavouring agent approved by FAO/WHO, has a vanilla odor four times that of vanillin and shows anti--mutagenic activity. There are two mol-ecules in the asymmetric unit, each having a planar conformation and an intramolecular O-H⋯O bond. Mol-ecules are connected side-by-side, building infinite ribbons along cvia inter-molecular O-H⋯O hydrogen bonds between the carbonyl and hydroxyl groups. The ribbons are then packed into layers perpendicular to the a axis.