10a-Hy-droxy-9-(4-meth-oxy-phen-yl)-3,4,5,6,7,8a,9,10a-octa-hydro-1H-xanthene-1,8(2H)-dione.

In the title compound, C(20)H(22)O(5), the tetra-hydro-pyran, cyclo-hexene and cyclo-hexane rings of the xanthene ring system adopt half-chair, half-boat and chair conformations, respectively. The mean plane of the four roughly planar atoms of the tetra-hydro-pyran ring (r.m.s. deviation = 0.111 Å) forms a dihedral angle of 82.91 (4)° with the meth-oxy-benzene group. In the crystal, mol-ecules are linked via O-H⋯O and C-H⋯O hydrogen bonds into sheets lying parallel to the ac plane. The crystal is further consolidated by weak C-H⋯π inter-actions.