The chemical composition of the hydrodistilled essential oil of Thymus guyonii de Noé, collected from Zelfana- Province of Ghardaia (Algerian Septentrional Sahara), was analyzed by GC and GC/MS. Nineteen components representing 94.63% of the essential oil were detected with carvacrol (55.55%), thymol (19.51%) and p-cymene (6.25%) as the major components. The antibacterial activity of the essential oil was tested against 9 gram-positive and gram-negative bacteria by the use of the disc diffusion method. The antioxidant activity was also investigated by the use of β-carotene bleaching method.
