The antimicrobial activities of chloroform, acetone and two different concentrations of methanol extracts of Ocimum basilicum
L. were studied. These extracts were tested in vitro against 10 bacteria and 4 yeasts strains by the disc diffusion method. The results indicated that the methanol extracts of O. basilucum
exhibited the antimicrobial activity against tested microorganisms. While the chloroform and acetone extracts had no effect, the methanol extracts showed inhibition zones against strains of Pseudomonas aeruginosa
sp., Listeria monocytogenes
, Staphylococcus aureus
and two different strains of Escherichia coli
. The cells of microorganisms, which were treated and untreated with plant extracts, were observed by using the scanning electron microscope. It was observed that the treated cells were damaged.