Introduction: bacterial diseases are of common diseases in human life and treatment of the diseases by means of antibiotics creates some other problems like drug resistance and side effects. So, using new herbal drugs with fewer side effects can help worthy in treatment of this kind of infections. The effect of Salvia officinalis Lam extract on four species of gram positive and gram negative i.e. Bacillus cereus, Bacillus anthracis, E.coli, Shigella sonnei. Extracting from herbs by distillation of pool water and by sink method was studied and chemical compound of the extract was analyzed by Gas Chromatography (GC) and gas chromatography connected to mass spectrometer. By calculating suppressive indices it was clear that there are 10 various compounds in the extract and the most important of them are: globulin (9.3%), α-humulene (8.4%), borneil (9.4%), α-penin1, 8 (5.5%) and cineol (18.9%). Efficient volatile oil against the mentioned bacterial suspensions was identified with 108 microorganisms per ml in order to study the rate of its antibacterial property. The antibacterial activity of Salvia officinalis Lam was observed as non-growth haloes after 24-28 hours. The haloes diameters were obtained as 40, 25, 24, and 20 mm for Bacillus cereus, Bacillus anthracis, Shigella sonnei, E.coli.
