Scandomelidine (1) is one of the five dimeric monoterpenoid indole alkaloids isolated from stems and leaves of Melodinus scandens Font. (Apocynaceae). It was obtained in minute amounts from the mother liquors of scandomeline, with a yield of 2.5 ppm from the dried raw material. The structures of the first four alkaloids (scandomelonine, scandomeline, their 19-epimers) have been reported previously. The structure of scandomelidine was established on the basis of spectroscopic evidence (elemental analysis, eims, uv, ir, ¹H nmr, ¹³C nmr) and results from the coupling of venalstonine [2] to pachysiphine [3] by a 10,3' bond. Spectroscopic data indicated it is a quasi-dimer consisting of a vincadifformine-like moiety (with an epoxide function on the D ring) and a venalstonine moiety. Comparison of ¹³C-nmr spectra with related alkaloids (criophylline, scandomelonine, etc.) confirmed the linkage site (C-10 of the vincadifformine-like moiety to the pachysiphine unit) and the orientation of the epoxide ring. Thus, structure 1 was assigned to scandomelidine.