Cyclea atjehensis (Menispermaceae), of Thai origin, has yielded the new aporphine (+)-N-formylnornantenine [1] which in CDCl₃ solution exists as a mixture of isomers 1a and 1b. Cyclea atjehensis Forman (Menispermaceae) is a vine native to Thailand where its extracts are sometimes used in folk medicine for the treatment of stomach disorders. Presently, an investigation of the alkaloidal contents of this plant has yielded a number of monomeric and dimeric bases. It is the monomeric bases that will be dealt with in this paper. Five alkaloidal monomers were isolated, which proved to be the pavinanes (-)-norargemonine and (-)-argemonine (1), and the aporphines (+)-laurotetanine, (+)-nornantenine, and (+)-N-formylnornantenine (2). This represents the first recorded occurrence of pavines within a member of the Menispermaceae. Of the five alkaloids, only (+)-N-formylnornantenine is new.