<p>The functions of multiple organs decline with the process of aging. Revealing the intrinsic mechanisms governing organ degeneration is a critical pursuit for understanding the aging process and creating interventions for aging-related diseases. Macromolecular damage caused by the generation of reactive oxygen species (ROS) increases with the process of aging. However, excessive ROS generation may only partially account for aging at the individual and organ levels. In contrast, they could serve as important signaling molecules in stress responses. In this review, we focused on the dual role of ROS in the aging processes of several human organ systems. Through this investigation, we aim to reassess the relationship between ROS and aging.</p>