For both plants, the aerial parts used of Lavandula Stoechas (LS) and Laurus Nobilis (LN) are leaves harvested during the flowering period. They give respectively (0.12%; 0.45%) and (0.326% 0.623%) by hydrodistillation essence. The constituents of the chemical composition have been identified by gas chromatography coupled to mass spectrometry (GC-MS). The essential oils leaves of LN and LN for two areas, "Zinat" and "Hallila" are very rich in oxygenated monoterpenes. Moreover, the biological effect, for essential oils of LS and LN possess an antibacterial activity against a bacteria Bacillus subtilis, except for LN has also the effect against Escherichia coli K12 and other bacteria don’t have the effect against Porteus sp, Staphylococcus aureus and Escherichia coli K12 LS of our species
