Background: Medicinal plants are used in treating diseases as low-risk, available and inexpensive natural materials with higher consumption by people comparing to synthetic antimicrobial drugs. Excessive use of antimicrobial drugs led to medicinal resistance against different antibiotics in most bacteria. Material and Methods: In this empirical experimental study, the antimicrobial effects of methanolic extracts of 14 medicinal plants species were examined comparing to conventional therapeutic antibiotics against standard bacterial strains. The plant species were collected from dashti of Bushehr province.The methanolic extract of the cultivations broths were prepared in different concentrations (0/25%, 0/5%, 1%, 2% and 4%) dissolved in DMSO/ Methanolic solution and their antibacterial potency respected on the inhibition zone using the disc diffusion assay. Results: The maximum effects on Escherichia coli belonged to Arundo donax and the least effects belonged to Calotropis procera. The maximum effects on Staphylococcus aureus belonged to Lawsonia inermis and the least effects belonged to Calotropis procera. The maximum effects on Micrococcus luteus belonged to Phoeniex doctylifera and the least effects belonged to Oligomeris baccatus. The maximum effects on Klebsiella pneumonia belonged to mnocarpos decander and the least effects belonged Oligomeris baccatus. The maximum effects on pseudomonas aeroginosa belonged to Arundo donax. The maximum effects on Bacillus subtilis belonged to Astragalus arbusculinus. Conclusion: The antimicrobial effects of 4% methanolic extracts of Arundo donax were comparable to Cephalotin (30mcg), Piperacilin (30mcg) and Amikacin (30mcg) against Escherichia coli and pseudomonas aeroginosa. The antimicrobial effects of %4 extracts of Lawsonia inermis were similar to Amikacin (30mcg) and Chloramphenicol (30mcg) against Klebsiella penumoniae.