in the recent decades, antimicrobial plant products have gained special interest because of the resistance to antibiotics that some micro-organisms have acquired. aromatic and medicinal plants are an important source of bioactive molecules, especially in volatile extracts, that are considered among the most important antimicrobial agents present in these plants. volatile components of artemisia herba-alba asso essential oil obtained by hydrodistillation growing in algeria (djelfacityof south algeria) were investigated by gc/fid and gc-ms. the major components were found to be camphor (39.5%), chrysanthenone (10.38%), 1,8-cineole (8.6%), -thujone (7.03%), borneol (3.35%) and bornyl acetate (2.52%). the essential oil has been tested for antimicrobial activity against gram-negative and gram-positive bacteria. inhibition of growth was tested by the agar diffusion method. the minimal inhibitory concentration (mic) was determined by the method of agar dilution.