This study concerned four plants known for their use in traditional medicine in south-eastern Tunisia (Rosmarinus officinalis, Thymus capitatus, Artemisia herba-alba and Artemisia campestris) whose leaves are commonly consumed as tea. We aimed to determine the chemical composition and the antioxidant activity of these aqueous extracts prepared in accordance with the traditional method (50g/L of water).Because of the containment of flavonoids, polyphenols, tannins and saponins, all aqueous extracts have electrical conductivity (total salts) which ranged from 1.12 for the R. officinalis extract to 4.82 mS/cm for A. herba-alba. The last one is the richest species in potassium (575 mg/L) and especially sodium (400 mg/L). The content of total phenolics varied from 77.7 GAE mg/L of T. capitatus extract to 306.35 mg GAE/L of A. campestris extract.The antioxidant activities expressed as IC 50 values varied from 3.17 μL extract/mL of DPPH solution for the extract of A. campestris (the most active) to 14.33 μL extract/mL for the of R. officinalis extract (the least active). Given these results, we can say that the consumption of these extracts could have preventive and curative benefits against several diseases. People suffering from stomach problems or high blood pressure should show great concerns to it because of the acidity and relatively high sodium content of these extracts.