This review literature focuses on the current state of green synthesis of copper and copper oxide (Cu/CuO)-based nanomaterial utilizing plant extracts as reducing and capping agents, and the paper discusses the antimicrobial applications of these biomaterials. Additionally, a novel hypothetical mechanism for the antimicrobial activity of biosynthesized Cu/CuO nanomaterial was proposed. This study will shed light on the future of the green production of Cu/CuO nanomaterial in antimicrobials. This review discusses the synthesis approach and the plant parts that have been utilized previously, allowing researchers to gain a brief understanding of the synthesis procedure employing plant extracts. Moreover, this paper includes an overview of the various analytical approaches used to characterize the produced nanomaterials and a summary of the microbial strains used in this area that have been studied thus far. Finally, the paper discusses the difficulties and potential prospectives associated with the synthesis of Cu/CuO nanomaterials from plant extracts.