Various results obtained from research on essential oils of vegetal aromatic species growing in Colombia are presented. In order to offer good scientific support to the essential oils agro-industry, the need for investigating a wide variety of topics is emphasized. Results of the chemical characterization and the antioxidant activity evaluation of 12 essential oils of 7 Lippia species are presented. The determination of the chemical composition of 12 essential oils of plants from genus Lippia, using gas chromatography coupled to mass spectrometry, showed that the most abundant and frequent constituents are oxygenated substances. The compositional diversity is manifested in optical isomers, in the existence of chemotypes with few substances in common, and in the diverse radical trapping modes, as evidenced by the ORAC and TEAC antioxidant capacity evaluations. While limonene and linalool were found in all the oils, 19 out of the 102 identified constituents of the set of oils studied were found in only one instance. The studied genus Lippia essential oils showed an antioxidant capacity higher than that exhibited by α-tocopherol or BHT, which are commonly used as antioxidants in commercial products for human consumption. Several species had a relatively high (1,5 – 4,4%) essential oil extraction yield, which together with their high antioxidant capacity convert these oils into good candidates to replace synthetic antioxidants. © 2014. Acad. Colomb. Cienc. Ex. Fis. Nat. All rights reserved.