Abstract Ocimum tenuiflorum L.f. (syn. O. sanctum L.) (Lamiaceae) is an indigenous ayurvedic medicinal plant of India and is popularly known as holy basil/sacred basil. Oils obtained by hydrodistillation from leaves, stems, inflorescence and whole herb were analyzed by GC and GC/MS and retention indices. Methyl eugenol was the major constituent of all the oils (72.5%, 75.3%, 83.7% and 65.2% in oils from whole herb, leaf, stem and inflorescence, respectively). Î²-Caryophyllene was the second most dominant constituent and the respective concentration in each oil (5.5%, 6.4%, 2.7% and 12.0%).