Both the federal Plain Writing Act and the mission of the US Centers for Disease Control and Prevention (CDC) to protect and promote people's health require CDC to communicate clearly so that people can understand and act on the important health information it provides. Decades of research shows that health information and services are often unfamiliar, complicated, and technical, even for people with many years of formal education. Although individual skills are important, the actions of health professionals in communicating health information are influential as well. In response to both the challenges faced by those who need health information and the opportunities for improvement among those who provide health information, CDC is taking steps to promote a clear communication culture to make its health information and services accessible and understandable by the different audiences it serves.