The antimicrobial activity of the aqueous and ethanolic extracts of Myrtus communis , Ammi visnaga , and Equisetum arvense was investigated against Staphylococcus aureus , Escherichia coli , and Candida albicans by using the agar well diffusion method. Serial concentrations (15%, 30%, and 50%) of the extracts of each plant were tested and compared with gentamicin (10 μg) and fluconazole (25 μg). Most of the extract concentrations showed a relatively high antimicrobial activity against all the tested microbes, and the ethanolic extract was more effective than the aqueous extract. The activity of plant extracts increased with the increasing extract concentration of Myrtus communis , which appeared to possess a more antimicrobial activity than the other plants assessed; in fact, its ethanolic extract exhibited the highest inhibition zone against S. aureus (32 mm). The ethanolic plant extracts at a concentration of 50% displayed the maximum activity against the herein assessed isolates. Moreover, E. coli showed a higher sensitivity to most extracts, while the lowest effect being noticed on C. albicans .