en علوم پایه پزشکی Basic Medical Sciences تحقیقی Original article <div style="text-align: justify;"><strong><em>Background and objectives</em></strong><em>:</em> As much as people become aware of the dangerous side effects of synthetic antibiotics, the demand for natural alternatives to these drugs increases. Natural ingredients, lower risk of complications and even have beneficial side effects. The aim of this study was to determine the antibacterial effect of herbs <em>Reum ribes L </em>and hyssop <em>Hyssopus officinalis </em>is on some pathogenic bacteria.<br> <strong><em>Methods:</em></strong> After collecting and confirming the scientific name, the methanolic extract of <em>R</em><em><span dir="RTL">.</span></em><em> ribes L.</em> and&nbsp; <em>H</em><em><span dir="RTL">.</span></em><em> officinalis</em>&nbsp; plants was prepared and the antimicrobial effects of the extracts by agar well diffusion and disk diffusion , as well as the determination of The minimum bactericidal concentration and the minimum inhibitory concentration (MIC / MBC)&nbsp; were dilution test on S<em>taphylococcus aureus, Bacillus cereus, Escherichia coli</em> and <em>Pseudomonas aeruginosa</em><em><span dir="RTL">.</span></em><br> <strong><em>Results:</em></strong> The highest growth inhibitory zone <em>in S</em><em><span dir="RTL">.</span></em><em> aureus, B</em><em><span dir="RTL">.</span></em><em> cereus, P</em><em><span dir="RTL">.</span></em><em> aeruginosa</em>, and <em>E</em><em><span dir="RTL">.</span></em><em> coli</em> at concentrations of 400 mg / ml, respectively, in the disc method of 13.21, 13.41, 11.2 and10.74 mm and the well method, respectively 13.64, 13.11, 10.67 mm, and 9.38 mm for the <em>R</em><em><span dir="RTL">.</span></em><em> ribes L</em> extract, and the disc method of 11.74, 10.2, 10.71, and 9.1 mm, and the well method of 12.41, 11.6, 10.2, and 9.9 respectively. 4.3 mm was observed for <em>H</em><em><span dir="RTL">.</span></em><em> officinalis</em> extract. The results of MBC / MIC showed that the extract of medicinal plants had the highest susceptibility to <em>B. cereus</em> bacteria and the least susceptibility to <em>E. coli</em><em><span dir="RTL">.</span></em><br> <strong><em>Conclusion:</em></strong> <em>R</em><em><span dir="RTL">.</span></em><em> ribes L.</em> and&nbsp; <em>H</em><em><span dir="RTL">.</span></em><em> officinalis</em>&nbsp; plants have significant inhibitory effects on the growth of pathogenic bacteria in vitro. Therefore, it can be expected that these extracts can be used for the treatment of bacterial infections and are a good alternative to the usual chemical treatments for the treatment of infections.<br> &nbsp;</div> Antibacterial effects,Pathogenic bacteria,Medicinal plants,Extract 34 44 http://goums.ac.ir/jorjanijournal/browse.php?a_code=A-10-563-1&slc_lang=en&sid=1 javad sayyahi taranoom.isi.isc@gmail.com 10031947532846005664 10031947532846005664 Yes Young Researchers and Elite Club, Ahar Branch, Islamic Azad University, Ahar, Iran Hayedeh Mobaiyen HayedehMobaiyen@yahoo.com 10031947532846005665 10031947532846005665 No Department of Microbiology, Tabriz branch, Islamic Azad University, Tabriz, Iran behboud Jafari dr.behboud.jafari@gmail.com 10031947532846005666 10031947532846005666 No Department of Microbiology, Ahar Branch, Islamic Azad University, Ahar, Iran Abolfazl Jafari-Sales a.jafari_1392@yahoo.com 10031947532846005667 10031947532846005667 No Young Researchers and Elite Club, Ahar Branch, Islamic Azad University, Ahar, Iran