The emergence of bacteria that are resistant to several antibiotics has represented a serious hazard to human health globally. Bioactive metabolites from medicinal plants have a wide spectrum of therapeutic possibilities against resistant bacteria. Therefore, this study was performed to investigate the antibacterial efficacy of various extracts of three medicinal plants asSalvia officinalisL.,Ziziphus spina-christiL., andHibiscus sabdariffaL. against pathogenic Gram-negativeEnterobacter cloacae(ATCC13047),Pseudomonas aeruginosa(RCMB008001),Escherichia coli(RCMB004001), and Gram-positiveStaphylococcus aureus(ATCC 25923), bacteria using the agar-well diffusion method. Results revealed that, out of the three examined plant extracts, the methanol extract ofH. sabdariffaL. was the most effective against all tested bacteria. The highest growth inhibition (39.6 ± 0.20 mm) was recorded againstE. coli. Additionally, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the methanol extract ofH. sabdariffawere detected in the case of all tested bacteria. Moreover, an antibiotic susceptibility test revealed that all tested bacteria showed multidrug resistance (MDR). While 50% of tested bacteria were sensitive and 50% were intermediately sensitive to piperacillin/tazobactam (TZP) based on the inhibition zone but still less than the extract. Synergistic assay demonstrated the promising role of using a combination ofH. sabdariffaL. and (TZP) against tested bacteria. A surface investigation using a scanning electron microscope of theE. colitreated with TZP, extract, or a combination of the two revealed extremely considerable bacterial cell death. In addition,H. sabdariffaL. has a promising anticancer role versus Caco-2 cells with IC50of 17.51 ± 0.07 µg/mL and minimal cytotoxicity upon testing versus Vero cells with CC50of 165.24 ± 0.89 µg/mL. Flow cytometric analysis confirmed thatH. sabdariffaextract significantly increased the apoptotic rate of Caco-2-treated cells compared to the untreated group. Furthermore, GC-MS analysis confirmed the existence of various bioactive components in the methanolhibiscusextract. Utilizing molecular docking with the MOE-Dock tool, binding interactions between n-Hexadecanoic acid, hexadecanoic acid-methyl ester, and oleic acid, 3-hydroxypropyl ester were evaluated against the target crystal structures ofE. coli(MenB) (PDB ID:3T88) and the structure of cyclophilin of a colon cancer cell line (PDB ID: 2HQ6). The observed results provide insight into how molecular modeling methods might inhibit the tested substances, which may have applications in the treatment ofE. coliand colon cancer. Thus,H. sabdariffamethanol extract is a promising candidate to be further investigated for developing alternative natural therapies for infection treatment.