A new monoterpene, crocusatin M (1), was isolated from the flower buds of Buddleja officinalis, together with four known monoterpenes, (6R)-hydroxy-1,1,5-trimethylcyclohex-4-enone (2), (+)-dehydrovomifoliol (3), 7-epiloliolide (4), and crocusatin D (5). Their structures were determined by an extensive analysis of 1D, 2D NMR, HRESI-MS, and CD data as well as by comparison of their spectroscopic data with those of literatures. All isolates were evaluated for inhibitory activities on LPS-induced nitric oxide production in RAW 264.7 cells. Among them, compounds 2 and 3 showed moderate inhibitory effects with $IC_{50}$ values of 63.8 and 24.4 ${mu}g/ml$, respectively.