A new pepluane diterpene polyester (2) was isolated from a CH2Cl2 extract of the whole, undried plant of Euphorbia peplus, together with the known compound 1. The structures were established by high-field spectroscopic methods, including 2D NMR techniques, and by X-ray crystallography, and the stereostructure of the first member of the pepluane diterpenoids (1) was revised.