By understanding the human microbiome and its influencing factors, oncology nurses in clinical practice can educate, screen, and monitor patients with cancer who have a higher risk of gut microbiome dysbiosis. Knowledge of the gut microbiome and its impact on cancer outcomes can help oncology nurses interpret associations between the gut microbiome and treatment- related toxicities and symptoms. Oncology nurses can guide patients to build a healthy gut microbiome across the trajectory of cancer treatment and survivorship.