RRx-001 is used in cancer therapy as a multifunctional anticancer agent. It acts as a radiosensitizer and chemosensitizer, enhancing the effectiveness of radiation and chemotherapy in resistant tumors. It selectively targets the tumor microenvironment, promoting oxidative stress in cancer cells while sparing normal tissues. RRx-001 also modulates the immune system by reprogramming tumor-associated macrophages toward an anti-tumor phenotype and stimulating systemic immune responses. It is being investigated in clinical trials for various solid tumors and hematologic malignancies, particularly in recurrent or metastatic settings. Its ability to cross the blood-brain barrier makes it suitable for treating brain tumors. Additionally, RRx-001 has shown potential in reversing multidrug resistance, improving outcomes when combined with standard therapies.