This chapter discusses the groundbreaking research on drugs that block one or more hallmarks of aging. Current studies seek to confirm the hypothesis that since aging is the prime risk factor for disease, inhibiting key age-promoting pathways will forestall the onset of disease and extend the health span. The reader is introduced to the hallmarks of aging and the biological effects of the prominent anti-aging drugs (metformin, rapamycin, sirtuins, and senolytics/senomorphs) in animals and man. Future challenges to this novel pharmacological approach to disease prevention are presented.