The title compound, C(14)H(18)O(4), a derivative of caffeic acid, has an E configuration about the C=C bond. The benzene ring is almost coplanar with the C=C-C(O)-O-C linker [maximum deviation = 0.050 (2) Å], making a dihedral angle of only 4.53 (2)°. In the mol-ecule, the adjacent hy-droxy groups form an O-H⋯O inter-action. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, generating a chain propagating in the [110] direction.