Nanotechnology involves creating, analyzing, and using tiny materials. Cobalt oxide nanoparticles (Co₃O₄ NPs) have several medicinal uses due to their unique antifungal, antibacterial, antioxidant, anticancer, larvicidal, anticholinergic, antileishmanial, wound healing, and antidiabetic capabilities. Cobalt oxide nanoparticles (Co₃O₄ NPs) with attractive magnetic properties have found widespread use in biomedical applications, including magnetic resonance imaging, magnetic hyperthermia, and magnetic targeting. The high surface area of Co₃O₄ leads to unique electrical, optical, catalytic, and magnetic properties, which make it a promising candidate for biomedical bases. Additionally, cobalt nanoparticles with various oxidation states (i.e., Co²⁺, Co³⁺, and Co⁴⁺) are beneficial in numerous utilizations. Co₃O₄ nanoparticles as a catalyzer accelerate the conversion rate of hydrogen peroxide (H₂O₂) to harmful hydroxyl radicals (^•OH), which destroy tumor cells. However, it is also possible to enhance the generation of reactive oxygen species (ROS) and successfully treat cancer by combining these nanoparticles with drugs or other nanoparticles. This review summarizes the past concepts and discusses the present state and development of using Co₃O₄ NPs in cancer treatments by ROS generation. This review emphasizes the advances and current patterns in ROS generation, remediation, and some different cancer treatments using Co₃O₄ nanoparticles in the human body. It also discusses synthesis techniques, structure, morphological, optical, and magnetic properties of Co₃O₄ NPs.