Much is published on the benefits of “fiber” in the diet. Nevertheless, there is some confusion over what constitutes dietary fiber. Moreover, some of its proclaimed benefits are controversial. Therefore, it is a challenge to determine if, how much, and what kind of fiber one should take. This article addresses the nature of dietary fiber; its sources; its commonly accepted benefits, especially for the intestinal tract; and how to achieve sufficient daily fiber intake. Reviewed and updated 2009.