Over the years, there have been many efforts to use antioxidants to prevent or help treat various diseases and aging. While reactive oxygen species (ROS), can damage and kill cells - these molecules have also been implicated in normal biochemical processes. Now, researchers have developed tools to study these ephemeral molecules in small quarters of the cell, and using these techniques, have shown that the cell manages the conflicting effects of ROS by sequestering the molecule to tiny compartments or nanodomains where it acts locally, without damaging surrounding organelles or DNA. The findings, published July 6th in the Cell Press journal Molecular Cell, provide new insight into how the cell uses this toxic but essential chemical.