A new eudesmanolide, 1α-acetoxy-8α,9β-dihydroxy-2-oxo-eudesman-3,7(11)-dien-8,12-olide (2), together with a known eudesmanolide, 1α-acetoxy-8α-hydroxy-2-oxo-eudesman-3,7(11)-dien-8,12-olide (1), and a known flavone, 4',5,7-trihydroxy-6-methoxyflavone (3), was isolated from the plant of Salvia plebeia. Three compounds were structurally elucidated by spectroscopic and chemical methods.