Tunisian Sour oranges leaves were studied. Alimentary preparations of C. aurantium were obtained by maceration, infusion, decoctions (15, 30 and 60 minutes). Different yields were obtained for different extractions. Their chemical composition was evaluated revealing few amounts of tannins and anthocyanins whereas some of them presented considerable ones of total phenolics (gallic acid equivalent 0,062 to 0,792 g/Kg Dry matter) and flavonoids (quercitin equivalent 0,039 to 0,694 g/Kg Dry matter). A screening of antioxidant activities was applied to all samples using DPPH and ABTS assays; their antimicrobial activities also were studied by 7 bacteria (3 Grampositive and 4 Gram-negative), 2 yeasts and 3 fungi. The alimentary mode of extraction influenced extracts chemical composition and their antioxidant activity. Correlations between chemical composition and antioxidant activity were studied.