The title quassinoid compound, C20H24O9·CH3OH·2H2O, is a natural eurycomanone isolated from the roots of Eurycoma longifolia. The molecules contain a fused five-ring system, with one tetrahydrofuran ring adopting an envelope conformation, one tetrahydropyran-2-one ring in a screw boat conformation, one cyclohexenone ring in a half-chair conformation and two cyclohexane rings in chair conformations. Intramolecular C—H⋯O interactions generate S(5) ring motifs and an O—H⋯O interaction generates an S(7) ring motif. In the crystal, molecules are linked via intermolecular O—H⋯O interactions along the b axis and further stacked along a axis. The absolute configuration of the title compound was inferred from previously solved structures of its analogues.