abnormal redox activity oxidative stress increased reactive oxygen species production increased ROS production condition characterized by an accumulation of free radical groups in the body, which creates a potentially unstable and damaging cellular environment linked to tissue damage, accelerated aging, and degenerative disease; can result from many factors, including exposure to alcohol, medications, poor nutrition, trauma, cold or toxins; may be indicated by low antioxidant levels measured in blood plasma MPheno.ontology MP:0003674