Fusobacterium nucleatum is a Gram-negative, anaerobic bacterium commonly found in the oral cavity, where it plays a crucial role in the formation of biofilms. Beyond its presence in the mouth, Fn is implicated in a variety of systemic conditions, including periodontal disease, colorectal cancer, and inflammatory bowel disease. Known for its ability to coaggregate with other bacteria, Fn’s pathogenic potential is magnified in dysbiotic microbial communities, making it a key player in polymicrobial infections. The bacterium utilizes multiple virulence factors such as FadA and Fap2, which facilitate adhesion to host tissues and immune evasion, ultimately contributing to its role in chronic and inflammatory diseases.