The objective of the present work was to study the antioxidant activity of the aqueous extract and the antibacterial activity of the Rosmarinus officinalis aerial part essential oils. The  Rosemary essential oil yield was equal to 1.47%. A great inhibitory power of Rosemary extract was revealed by the test of antioxidant activity (93.72%) by an IC₅₀ of 16.95 µg/ml, which was superior to that of Butylated hydroxy anisol (BHA a synthetic antioxidant) (6.01µg/ml), and of ascorbic acid (1.27µg/ml).  The essential oil antibacterial activity was evaluated against five bacterial strains, using the aromatogram method. Hence, a remarkable antibacterial activity was noted for Rosemary essential oil.  Gram-positive bacteria were highly sensitive to the activity of this essential oil than the Gram-negative bacteria. Furthermore, pharmacological investigation of the plant aqueous extract revealed the plant had very important pharmaceutical effects (anti-inflammatory effect). The preliminary study of toxicity, according to oral voice, revealed that the Rosmarinus officinalis leaves were not toxic.