Bioactivity-guided isolation of a MeOH extract of <i>Aralia cordata</i> led to the isolation of four new <i>ent</i>-pimarane diterpenoids (<b>1</b>-<b>4</b>) and a diacetylene (<b>5</b>) together with 21 known compounds (<b>6</b>-<b>26</b>). Their structures were established based on the interpretation of one- and two-dimensional NMR and HRESIMS data. The absolute configurations of the new isolates were determined by electronic circular dichroism data analysis, single crystal X-ray diffraction, and Mosher's esterification method. All compounds exhibited inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophages with IC<sub>50</sub> values ranging from 1.1 to 69.4 μM.