In the title compound, C(12)H(12)O(4), the dihedral angle between the plane through the phenyl ring and the mean plane of the side chain is approximately 14°. The mol-ecules, which contain an intra-molecular O-H⋯O hydrogen bond, are linked end-to-end by weak C-H⋯O inter-molecular hydrogen-bonding contacts, forming infinite one-dimensional chain systems in the crystal structure.