Nishimura and Kubo isolated a strain of Fungi Imperfecti which produces an antifungal metabolite. The metabolite was obtained in a crystalline state from the mycelia extract. The elementary analysis and spectral data implied that the compound is a dihydric alcohol containing a carbonyl group. A crude metabolite was purified by acetylation and a preparative TLC to give colorless needles, m. p. 129-130℃, of the molecular formula CzoHl,Os. In the NMR spectrum of the acetate two acetoxyl groups and a secondary methyl group were inferred from the singlet signals at r 7.91, 8.0, and 8.77 respectively. A couple of quartet at r 2.8 (1H) and 4.35 (1H) were indicative of the partial structure (B). Based on the molecular formula and spectral data, it was deduced that the antifungal metabolite is a dihydroxy bicyclic diene ester (or lactone) or a dihydroxy monocyclic triene ester (or lactone). The physical properties including IR and NMR data of the acetate agreed in every respect with those of brefeldin A diacetate.