Abstract Gymnopusin, the first naturally occurring phenanthrenederivative having a hydroxyl group at C-9, was isolated from the orchidBulbophyllumgymnopus . It was shown to be 7,9-dihydroxy-2,3,4-trimethoxyphenanthrene ( 1a ) mainly from the spectral data of the compound and those of its diacetyl ( 1b ) and dimethyl ether ( 1c ) derivatives.