Michelaine (1), (-)-anonaine, (-)-norushinsunine, (-)-ushinsunine, (-)-N-acetylanonaine, liriodenine, atherospermidine, (+)-syringaresinol, N-trans-feruloyltyramine, p-hydroxybenzaldehyde, vanillin, vanillic acid, syringic acid, coniferyl aldehyde, syringin, scopoletin, 4-acetonyl-3,5-dimethoxy-p-quinol, beta-sitostenone, and stigmasta-4,22-dien-3-one were isolated from the flowers of Michelia alba (Magnoliaceae). Among them, michelaine (1) is a new 4,5-dioxoaporphine compound. The structures of these compounds were characterized and identified by spectral analyses.