The concept of source control encompasses all of the physical interventions, surgical and otherwise, that are used to treat infection. Although source control is one of the most important aspects of the treatment of serious infection, it has received relatively little attention. It is the topic of this overview, which draws heavily on a book we edited recently: Source Control: A Guide to the Management of Surgical Infection (Springer-Verlag, 2002). The first section focuses on general considerations: historical perspective, scientific basis, and surgical principles of source control. The second section highlights specific considerations of source control in various situations.