Medicinal plants have long played a vital role in sustaining life on Earth. Mentha arvensis (mint leaves) and Cymbopogon citratus (lemongrass) were collected under sterile conditions and transported to the laboratory at Usmanu Danfodiyo University, where they were air-dried for 3 weeks. Plant biomass was ground into powder using a mechanical grinder at a 10:90 ratio. Fresh samples were processed for preservation and deposition in the herbarium. The plant biomass was soaked with analytical-grade reagents obtained from Joechem Ventures in Rivers State, Nigeria. After removal of the solvent by standard Soxhlet extraction, the extract underwent physicochemical, proximate, and antimicrobial analyses. Bacterial isolates were obtained from virulent samples collected from slaughterhouse effluent in Badagry, Lagos State, and identified by 16S rRNA gene sequencing of genomic extracts. The well-in-agar approach was used to assess antibacterial potency. Mentha arvensis and Cymbopogon citratus, commonly known as mint leaves and lemongrass, respectively, had accession numbers ECU-FS-EE01 and ECU-FS-EE02. Phytochemical components such as flavonoids, alkaloids, phenols, tannins, and glycosides were identified in the leaves of both plants used in the study, and steroids were confirmed in Mentha arvensis. The crude lipid, fiber, and protein contents of Mentha arvensis were 3.12%, 5.83%, and 4.39% w/w, respectively, while those of Cymbopogon citratus were 3.69%, 8.21%, and 4.03% w/w, respectively. The biomass yields of Mentha arvensis leaves were 3.18, 5.08, and 6.33 g/w in water, ethyl ether, and n-hexane, respectively, while those of Cymbopogon citratus were 4.67, 6.17, and 6.445 g/w in the same solvents. The mint leaf extract exhibited optimal activity against the isolates, with Proteus hauserii identified as the most resistant and Providencia stuartii as the most sensitive to the ethyl ether extract. Synergistic evaluation indicated that a 70:30 mixture of mint leaves and lemongrass in ethyl ether exhibited the strongest synergy against the bacterial isolates. There is a need for academia to develop a robust library of pharmaceutical preparations to combat virulent bacteria that commonly interact with humans and their ecosystems.