Venous thromboembolism (VTE) is a clinically silent and potentially fatal disease that manifests as deep vein thrombosis (DVT) and pulmonary embolism. Venous thromboembolism remains a serious public health challenge, with an ever-increasing odds ratio of occurrence given the aging population in the United States. This article reviews the epidemiology of VTE; risk factor identification and stratification as a means of advancing awareness, prevention, and detection of VTE; and prophylaxis options and their outcomes, particularly administration of unfractionated heparin (UFH) 5000 U subcutaneously every 12 versus 8 hours in the at-risk medical patient population. The important studies comparing outcomes of these different UFH dosing regimens compared with placebo and low-molecular-weight heparins also are discussed. Consensus recommendations shaping contemporary clinical practice guidelines in this setting are highlighted. A systemwide approach to treatment of all medical patients who are risk stratified and receiving appropriate pharmacologic prophylaxis is recommended.