The health and longevity effects of body weight reduction resulting from exercise and caloric restriction in rodents are well known, but less is known about whether similar effects occur with weight reduction from the use of a pharmaceutical agent such as sibutramine, a serotonin-norepinephrine reuptake inhibitor. Using data from a 2-year toxicology study of sibutramine in Sprague-Dawley CD rats and CD-1 mice, despite a dose-dependent reduction in food intake and body weight in rats compared with controls, and a body weight reduction in mice at the highest dose, there was no compelling evidence for reductions in mortality rate.