Thrombosis, an important complication of atherosclerosis and of various medical and surgical conditions, can be prevented and treated effectively by a variety of pharmacologic agents. With an update of previous editions publications, this boo provides a summary of the 2004 American College of Chest Physicians (ACCP) recommendations, together with a brief review of the background data on which the recommendations are based. Literature searches were conducted by a recognized evidence-based center at McMaster University.