From bulbs of Crinum americanum oxocrinine, an intermediate in the biosynthesis of Amaryllidaceae alkaloids, was isolated for the first time. In addition, the plant contains crinine, flexinine, O-acetylcrinine, lycorine, hippadine, pratorinine, pratorimine, pratosine, ungeremine and trisphaeridine. The alkaloids were identified by spectroscopic evidence, chemical transformations and partial syntheses. © 1986.