Antibiotic-resistant bacteria are a serious health concern. Increasing numbers of bacterial infections are unresponsive to traditional antibiotics. Various plant extracts have been demonstrated to contain ingredients that enhance the potency of conventional antibiotics. This study used the Kirby-Bauer disk diffusion method to investigate the antibacterial properties of extracts of peppermint (Mentha piperita), thyme (Thymus vulgaris), and green tea leaves (Camellia sinensis), when applied alone or in combination with the conventional antibiotics bacitracin, ciprofloxacin, erythromycin, or penicillin against three common human pathogens: Escherichia coli, Staphylococcus epidermidis, or Pseudomonas aeruginosa. All tests were performed in triplicate. Zones of growth inhibition were measured in millimeters and compared statistically using two-sample Student's t-tests. Results indicate that thyme extract partially reverses the resistance of E. coli to bacitracin and penicillin. Additionally, peppermint extract shows synergistic activity when combined with ciprofloxacin against P. aeruginosa, while green tea extract shows synergistic activity with erythromycin against P. aeruginosa. In addition to these positive results, several antagonistic combinations were also identified. These data both confirm previously published studies and demonstrate novel interactions between these plant extracts and antibiotics. Further research into this relatively unexplored field could lead to the development of naturally derived medicinals that enhance the effectiveness of traditional antibiotics.