Background & objectives: History of medicinal plants in healing the pains goes back to five thousand years ago. In addition, strong antibacterial properties have been observed in many of these plants. In this research, the effect of aqueous and ethanolic extracts and also homogenized form of scrophularia striata was examined on some respiratory and urogenital tract bacterial pathogens.

Methods: At first, bacterial isolates susceptibility test was done by kerby-bauer disc diffusion method and positive control was determined for every isolate. Then, several dilutions (1000, 500, 250, 125, 62.5 mg/ml) of aqueous, ethanolic and homogenized extracts were prepared in distilled water separately. Thirty microliter of each diluted extract was inoculated on sterile blank disc and minimum inhibitory concentration was examined for every studied bacteria by E-test. Minimum inhibitory and bactericidal concentration of extracts was determined by macrodilution method.

Results: Based on the results, smaller inhibitory zone than inhibitory zone of positive control was observed only with high concentration of aqueous extract in mannheimia haemolytica and with serial dilutions of ethanolic and homogenized extract in trueperella pyogenes, and with homogenized form in corynebacterium renale. No response was observed with other bacteria. Ethanolic extract showed bactericidal property with 62.5 mg/ml concentration and bacteriostatic property with 125 mg/ml concentration on mannheimia haemolytica which was similar to effect of this extract and homogenized form on trueperella pyogenes.

Conclusion: According to the results of this study and common application of this plant in respiratory and urogenital tract infections treatment, study on the role of different bacteria in this infections or effect of this extract on immune system stimulation can be recommended