<jats:p>Psychotridine, the major alkaloid from Psychotria beccarioides Wernh. has the molecular composition C55H62N10. It has been shown to be related to hodgkinsine, and a structure (4) derived from five Nb-methyltryptamine units is proposed. Mass spectral evidence for the structure is supported by the conversion of psychotridine through a pentamethiodide into a penta-indolenine base, analogous to the tri-indolenine base derived from hodgkinsine Nb,Nb',Nb?-trimethiodide. The structure is also supported by comparison of the 13C N.M.R. spectra of hodgkinsine and psychotridine.