Dihydroethidium (DHE) is widely used as a fluorescent probe to detect and measure superoxide anion production in biological systems. When DHE reacts with superoxide, it forms a red fluorescent product, 2-hydroxyethidium, which can be visualized and quantified using fluorescence microscopy, flow cytometry, or spectrophotometry. This makes DHE a valuable tool in research studies focused on oxidative stress, particularly in understanding the role of reactive oxygen species (ROS) in various diseases such as cardiovascular disorders, neurodegenerative conditions, and cancer. Additionally, DHE is utilized in pharmacological studies to evaluate the efficacy of antioxidants and other compounds that modulate ROS levels. Its specificity for superoxide, compared to other ROS, allows researchers to gain insights into cellular mechanisms and pathways involved in oxidative damage and signaling.