A new eremophilane sesquiterpenoid, namely, $3{eta}$-angeloyloxy-$6{eta}$,$8{eta}$-dihydroxy-$9{eta}$-senecioyloxyeremophil-7(11)-en-12,$8{alpha}$-lactone, along with eight known sesquiterpenoids, was isolated from the rhizome of Farfugium japonicum. The structures of all isolates were identified based on analyses of spectroscopic data (HRESIMS, IR, 1D, and 2D NMR) and comparison with literature data. The inhibitory effects of compounds 1-4 on nitric oxide production in lipopolysaccaride-activated mouse macrophages were also evaluated.