Nardosinone was isolated as an enhancer of nerve growth factor (NGF) from Nardostachys chinensis. Nardosinone (0.1-100 microM) enhanced dibutyryl cyclic AMP (dbcAMP, 0.3 mM)- and staurosporine (10 nM)-induced neurite outgrowth from PC12D cells in a concentration-dependent manner, suggesting that Nardosinone enhances a downstream step of MAP kinase in the MAP kinase-dependent signaling pathway.