Life expectancy has dramatically increased in industrialized countries since the 1900s due to advances in disease prevention and treatment, and improvements in nutrition and infant mortality. Thus, as a society we are living longer and experiencing more of the changes and declines associated with aging. Although the factors that cause our bodies to age are unknown, various medical interventions have been proposed and explored to prevent the process. Published research on aging conducted during the past 10 years was retrieved through MEDLINE and critically evaluated. Animal and human studies suggest potential benefits of dietary modification, exercise, antioxidants, hormones, and deprenyl. Due to the interrelationships between disease and older age and the limitations of existing research in this area, most life extension strategies are untested hypotheses. Many strategies merit scientific inquiry, but they cannot be recommended for use. More extensive research is necessary to assess their safety, effectiveness, and socioeconomic impact, and to resolve ethical controversies before they can be considered applicable in humans.