The title compound, commonly known as (+)-(6aS,11aS)-medicarpin, C16H14O4, was isolated from Dalbergia oliveri and displays a rigid molecule consisting of four fused rings. The benzofuran system is inclined at an angle of 76.49 (2)° with respect to the chroman unit. The compound exists as a polymeric chain arising from intermolecular O—H...O bonding.