From the Me 2 CO extract of the whole plant of Euphorbia boetica a new tetracyclic diterpene was isolated. Its structure was established based on NMR spectroscopic data obtained using a combination of one- and two-dimensional techniques. The known steroids 5α-stigmastane-3β-6α-diol, 5α-stigmastane-3β-5,6β-triol and β-sitosterol glucopyranoside were also isolated.