The isolation 1,2 and structural eluoidation2 of a-, β-, γ- and δ-caesalpins from the seeds of Caesalpinia bonducella have been reported. We have isolated, from the same source, a new crystalline compound, ε-caesalpin, which is assigned structure (I) (or enantiomer) on chemical and spectroscopic evidence. This is confirmed by an X-ray analysis of the p-bromobenzoate (II) which, in addition, establishes the stereochemistry at the remaining asymmetric centres and the absolute configuration as in (III).