Isolation of main chemical compound from dichlorometane extract of G. cowa’s stem bark has been done. The ground air dried stem bark (2 kg) was given 20,3 grams thick extract of n-hexane and 76,76 grams thick extract of dichlorometane. Separation was conducted by colomn chromatography and radial chromatography. The purification was carried out trough crystallisation. FM was isolated as yellow needle crystal (1,013), with Rf value 0,55 and melting point at 207-209 oC. On other hand, DM was also obtained 132 mg of yellow amorphous compound, with Rf 0,75 and melting point at 218-220 oC. The rendemen of FM is 2,53%, while for DM is 0,33%. Based on Melting point, thin layer chromatography profile using standard compound, ultraviolet and Infrared spectra, FM is identified as rubraxanthone.