The metabolites of Aspergillus terreus IFO 6123 were studied. 3-Methylorsellinic acid, 4-O-demethylbarbatic acid and a new metabolite named asterriquinone were isolated. The chemical structure of asterriquinone was established as 2, 5-bis-[N-(1", 1"-dimethyl-2"-propenyl)-indoyl-3']-3, 6-dihydroxy-1, 4-benzoquinone by chemical and physical experimental data. The incorporation experiments using ¹4C-labeled compounds showed that asterriquinone is biosynthesized from tryptophan and isopentenyl unit derived from mevalonate.