RESUMEN
In recent years, a new view has been stablished toward pharmaceutical plants and applicational use of them all over the world and researchers, in various medical courses are investigating about this issue. On this basis, antibacterial effect of Humulus lupulus, the pharmaceutical plant which has an important place in traditional medicine of Iran, was evaluated on some of bacteria. Based on scientific methods after being dried, prepared extract by using macerasion method. Antibacterial effects of ethanol extract were studied on Staphylococcus aureus [1112PTCC], Escherichia coli [1276PTCC], Bacillus subtilis [1023PTCC], Psedomonas aeroginosa [1430PTCC], by using spreading method, well plate method and MIC. The ethanol extract of Humulus lupulus showed antimicrobial activity on S. aureus and B. subtilis. The extract exhibited antimicrobial activity at a range of 125 mg/ml to 62/5 mg/ml against S. aureus and B. subtilis respectively. With the increase of worldwide antibiotic resistance of many strains of disease producing bacteria, there is a need to access new and complementary approaches to antibiotic therapy. Extract of Humulus lupulus has antibacterial effect. The antimicrobial activities of Humulus lupulus against a variety of gram positive bacteria confirm its use for treatment of infectious