The new pyrrolidone alkaloid donaxanine, C12H14N2O2, has been isolated from Arundo donax. Its structure has been shown by chemical transformations and a study of its IR, mass, and PMR spectra as spiro[(N-methylpyrrolidin-2-one)-3,4′-(3′,1′-benzoxazine). © 1996, Plenum Publishing Corporation. All rights reserved.