The trunk wood and root of Maytenus guianensis contain 4′-O-methyl-(-)-epigallocatechin, proanthocyanidin A, dulcitol, sitosterol, β-sitostenone and friedelan-3,7-dione. The trunk wood also furnished N,N-dimethylserine. A new sesquiterpene alkaloid, named mayteine, was isolated from the root. © 1986.