Free radicals are unstable atoms that cause damage to cells and DNA in the body. They are also known as reactive oxygen species or ROS. To combat the harmful effects of free radicals, antioxidants are essential. Antioxidants neutralize free radicals and help to protect the body from oxidative stress. There are many different synonyms for free radicals including reactive oxygen species (ROS), oxidants, pro-oxidants, and radical oxygen species. Other terms such as oxidative stress, oxidative damage, and oxidative injury are also used to describe the damage caused by free radicals. Understanding these different terms can help individuals make informed decisions about their diet and lifestyle choices to help prevent or minimize the damaging effects of free radicals.