Abstract Introduction: Good hand hygiene is an important measure to avoid the transmission of infectious agents in the hospital and in the community. This study aimed to investigate the antimicrobial effects of Citrus aurantifolia (key lime) juice and the aqueous extract of Cymbopogan flexuosus leaves on the growth of Staphylocuccus aureus and Escherichia coli. Methods: Antimicrobial activity was quantitatively evaluated by spectrophotometry and viable cell count versus bacterial growth time. The efficacy of the plant extracts and the commercial hand wash product was also compared by measuring the number of bacterial colonies before and after using C. aurantifolia juice and commercial hand wash product. Results: In the kinetic growth study, C. aurantifolia juice and the aqueous extracts of C. flexuosus leaves effectively eliminated S. aureus and E. coli. C. aurantifolia juice also efficiently removed most of the microorganisms on the volunteers’ hand, indicating a significant finding in human trial compared to in vitro study. The percentage of microorganisms left after hand washing with C. aurantifolia juice was significantly reduced to 91.72 %, which was comparable with that of the commercial hand wash product (82.87 %). Conclusion: This study showed that these plant materials are promising alternatives for antibacterial agents in hand wash products. Further studies should be conducted on the use of C. aurantifolia juice as hand sanitiser given its antibacterial activities against endemic microbes