Abstract The chemical composition of essential oils from leaves, stem bark, stem wood, root bark and root wood of five populations of Pilocarpus spicatus, collected in the northeast of Brazil, were compared by GC/MS. The aliphatic ketones 2-undecanone, 2-tridecanone and 2-pentadecanone were present in samples of all populations. 2-Tridecanone (1.7â84.7 %) was detected in 30 out of 34 samples analyzed. It was the main component in all samples of root barks, except one where 2-pentadecanone (24.7%) was the major component. 2-Undecanone, Î²-eudesmol and sabinene were the major components of leaf oils.