Many plants play important role in pharmaceutical, food, medicine and
   cosmetic industries for their volatile oils. Numerous studies have been carried
   out on various plant species and effect of their essential oils or extracts on
   microorganisms. In the present study antibacterial effect of Iranian thyme
   on two pathogens of E.coli and S.aureus, is reported for the first time.
   Antibacterial property of thyme oil is compared with that of ampicillim.

          Essential oil of Thymus x-porlock was extracted by steam distillation and
   its antimicrobial effects on E.coli and S. aureus were studied. Disc diffusion
   method was conducted to evaluate the zone of microbial growth inhibition.
   The antibacterial effect was also studied against three different
   concentrations of microbial suspension to find out MIC (Minimal Inhibitory
   Concentration) and MBC (Minimal Bactericidal Concentration).The results
   were compared with those of ampicillin.

          Fresh oil from Thymus x-porlock at 1/16 and 1/8 dilutions inhibited E.coli  
   and S.aureus growth with 17mm and 22mm microbial growth inhibition
   zones respectively.  Ampicillin at 4 mg/ml concentration was bactericidal
   against E.coli showing 11mm zone of microbial growth inhibition. Ampicillin
   was bactericidal against S.aureus at 6mg/ml concentration with 23mm
   growth inhibition zone.

          The essential oil of thyme showed a very good bactericidal activity
   within shorter time than that of ampicillin.