© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Ocimum basilicum (Lamiaceae) commonly known as Sweet Basil is an aromatic plant having a controversial carcinogenic effect and is also used in the food industry. This study was designed to evaluate the chemical constituent by the chemometrics-assisted-GCMS and the antioxidant activity of the O. basilicum L. herb gathered from Sivas. Twenty-one ingredients representing 92.30% of the total oil were identified in the essential oil of O. basilicum L. The major ingredients were noted as methyl eugenol 52.97%, α-cubebene 10.82%, and spathenole 6.92%. The results were compared with other studies on the content of the O. basilicum L. plant. DPPH and β-carotene-Linoleic acid assays revealed considerable antioxidant activity of methyl eugenol-rich O. basilicum essential oil, which is lower than standard BHT, and higher than standard methyl eugenol. Multivariate curve resolution-alternative least squares (MCR-ALS) which is an iterative method was used for resolving the overlapped and embedded peaks. The results of this study show that chromatographic methods combined with MCR-ALS analysis techniques can be useful for a comprehensive, rapid, and specific analysis of complex natural products such as O. basilicum essential oils. In recent studies, the carcinogenic effects of methyl chavicol and methyl eugenol, the dominant active ingredients of O. basilicum L. were pointed.