By envisioning adolescence as an ideal time to promote good physical health, it is possible to save lives and set in motion a lifetime of good health outcomes. To identify programs that promote health, this brief summarizes experimental studies of health-related behaviors, and reviews more than 230 research studies to identify factors associated with better health-related behaviors and fewer accidents and injuries. Among the programs found to succeed in helping teens adopt a healthy lifestyle are those that take a multifaceted approach to promoting positive health behaviors, incorporating psychosocial and behavioral components, instead of simply distributing information. Programs should also work to achieve desirable health behavior changes that endure over time, not just in the short term. This is a particular challenge among adolescents. Similarly, programs that aim to prevent injury among teens are most effective when they reach adolescent males (who are most likely to engage in such behaviors), address risky behaviors, and are multifaceted. This brief is divided into two sections. The first addresses issues related to promoting healthy lifestyles among teens, including smoking, exercise and nutrition, and sleep. The second section focuses on preventing unintended injury, including car and bike accidents, and occupational injuries. (Contains 85 references.) (GCP)