Four new 3,4-seco-labdane diterpenoids,nudiflopenes J-M,were isolated from the leaves of Callicarpa nudiflora along with six known compounds.The structures of these diterpenoids were determined by comprehensive spectroscopic analysis.All the isolated compounds were evaluated for their inhibitory effects on NO production in LPS-stimulated RPMs and RAW264.7 cells.The results suggest that nudiflopenes J-M and other four known compounds showed significant inhibitory effects against NO production comparable to the positive control dexamethasone.