The title compound, C6H6O3, is a member of the pyrone family. The mol-ecules are planar (r.m.s. deviation of the asymmetric unit is 0.0248 Å, whereas that of the dimer is 0.0360 Å) and they are dimerized due to inter-molecular O - H?O hydrogen bonds. The dimers are connected to each other through hydrogen bonds involving the CH3 group and the hydr-oxy O atom. There are ?-? inter-actions between the centroids of the pyrone rings at a distance of 3.8552 (13) Å. A C - H?? inter-action also exists between the carbonyl group and the centroid CgA of the pyrone ring, with O?CgA = 3.65 (1) Å and C?CgA = 4.363 (2) Å.