Bark of Virola sebifera used in the preparation of hallucinogenic snuffs and drinks in Venezuela has yielded N-methyl-N-formyltryptamine and N-methyl-N-acetyltryptamine, which exist in two rotameric forms reflecting hindered rotation around the carbon-nitrogen bond of the amide function. They were detected by HPLC as well as NMR. 2-Methyl-1,2,3,4-tetrahydro-beta-carboline, N,N-dimethyltryptamine, its oxide and N-monomethyltryptamine were also identified. Key Word Index-Virola sebifera Myristicaceae;hallucinogenic plant; alkaloids N-methyl-N-acetyltryptamine; N-methyl-N-formyltryptamine; 2-methyl-1,2,3,4_tetrahydro-beta-carboline;N,N-dimethyltryptamine; N,N-dimethyltryptamine-N-oxide; N-monomethyltryptamine.