Bacterial nanocarriers represent a promising approach for site-specific drug delivery, offering precise targeting and controlled release of therapeutic agents. This review provides an overview of the application of bacterial nanocarriers in precision medicine, focusing on their potential to target specific sites within the body for enhanced therapeutic outcomes. The key characteristics of bacterial nanocarriers, including size and shape, surface modifications for targeting and stealth capabilities, payload capacity, loading efficiency, stability, and biocompatibility, are discussed. This review explores various types of bacterial nanocarriers, including bacterial outer membrane vesicles (OMVs), bacterial spores, engineered bacteria, and other bacteria-based nanocarriers, highlighting their unique properties and applications. The mechanisms of site-specific drug delivery, including passive targeting via the enhanced permeability and retention (EPR) effect, active targeting using ligands and receptors, and tumor microenvironment-specific activation, are examined to elucidate the precise delivery mechanisms employed by bacterial nanocarriers. Furthermore, this review discusses the diverse applications of bacterial nanocarriers in precision medicine, including cancer therapy, infectious diseases, and chronic diseases, emphasizing their potential for targeted delivery of chemotherapeutic agents, immunotherapy, antibiotics, vaccines, and sustained release formulations. Challenges such as immunogenicity, manufacturing scalability, regulatory hurdles, and approval processes are addressed, along with future directions and emerging technologies in the field. Overall, bacterial nanocarriers hold immense promise as versatile platforms for site-specific drug delivery, paving the way for advancements in precision medicine and personalized therapeutics.