A new sesquiterpene, neolindenenonelactone (1), was first isolated from the dried roots of Lindera aggregata (SIMS) KOSTERM., along with four known compounds, linderane (2), isolinderalactone (3), linderalactone (4), and 8-hydroxylindestenolide (5). Their chemical structures were elucidated using spectral analysis of fast atom bombardment mass spectroscopy, one-dimensional nuclear magnetic resonance spectroscopy and two-dimensional-nuclear magnetic resonance spectroscopy including (1)H-NMR, (13)C-NMR, distortionless enhancement by polarization transfer, heteronuclear multiple-bond coherence, and single-crystal X-ray diffraction techniques.