This variation depends on the nature and the concentration of the antioxidant used. A relatively high antioxidant activity isnoticed for rosemary extract and was estimated at 81% for a concentration of 0.08%. This activity was significantly better (p < 0.05) thanthat provided by BHT used at a concentration of 0.1% and which inhibits only 52% of free radicals. This shows that the prepared RE contains compounds which are responsible for a free radicalscapture and therefore could be used to stabilize and retard oil oxidation. This antioxidant activity can be attributed especially to the presence of carnosic acid and carnosol previously identified in the RE