The title compound, C(16)H(12)O(5), was isolated from Morinda officinalis How. The anthraquinone ring system is almost planar, the dihedral angle between the two benzene rings being 1.12 (4)°. In the crystal structure, O-H⋯O and C-H⋯O hydrogen bonds link the mol-eculesin the crystallographic a-axis direction. Weak π-π stacking inter-actions [centroid-centroid distance between symmetry-related benzene rings of 3.699 (4) Å] are also present.