Superparamagnetic iron oxide nanoparticles (SPION) are widely used in biomedical applications such as magnetic resonance imaging, targeted drug delivery, and hyperthermia. While their benefits are significant, there is a need to identify potential cellular damage associated with these nanoparticles. This review focuses on cytotoxicity, DNA damage, and oxidative stress, as well as other subtle cellular alterations. SPION can cause cellular perturbations, including modulation of the actin cytoskeleton, altered gene expression profiles, disturbance in iron homeostasis, and changes in cellular responses such as signaling pathway activation and cell cycle regulation. The importance of protein-SPION interactions and safety considerations related to exposure are also discussed. The review highlights the need for comprehensive investigations into the biological consequences of SPION exposure to ensure their safe use in various biomedical applications.Superparamagnetic iron oxide nanoparticles (SPION) are widely used in biomedical applications such as magnetic resonance imaging, targeted drug delivery, and hyperthermia. While their benefits are significant, there is a need to identify potential cellular damage associated with these nanoparticles. This review focuses on cytotoxicity, DNA damage, and oxidative stress, as well as other subtle cellular alterations. SPION can cause cellular perturbations, including modulation of the actin cytoskeleton, altered gene expression profiles, disturbance in iron homeostasis, and changes in cellular responses such as signaling pathway activation and cell cycle regulation. The importance of protein-SPION interactions and safety considerations related to exposure are also discussed. The review highlights the need for comprehensive investigations into the biological consequences of SPION exposure to ensure their safe use in various biomedical applications.