 Oxidative stress is a concept in redox biology and medicine that was first formulated in 1985. Since then, it has become increasingly important in understanding how cells respond to changes in their environment. It is defined as the imbalance between the production of free radicals and the body's ability to neutralize them. Free radicals are highly reactive molecules that damage DNA, proteins, and lipids, leading to cellular dysfunction and death. When the body cannot keep up with the production of free radicals, oxidative stress occurs. Research into oxidative stress has focused on understanding the mechanisms behind the production of free radicals and the body's response to them. Recent advancements have allowed scientists to better understand the role of oxidative stress in various diseases such as cancer, diabetes, and Alzheimer's. This article was authored by Helmut Zeiss.