No standard exists for venous thromboembolism (VTE) prophylaxis after traumatic brain injury (TBI). Caregivers agree that there is an early time point after injury in which the chances of spontaneous injury progression are high and the risks of prophylactic anticoagulation are excessive, and that these injuries eventually stabilize to the point that anticoagulation may be safely started. Translating this consensus into an application that can inform bedside decision making has not occurred. National groups have promulgated guidelines in the United States suggesting that anticoagulants be used when the risk of renewed intracranial hemorrhage has ceased with no guidance beyond this vague recommendation. This is largely due to the relative paucity of literature about pharmacologic prophylaxis, which has in turn been due to fears of propagation of intracranial hemorrhage. Although interest in this field has increased of late, many studies are limited by the simple dichotomization of TBI patients as having the presence or absence of intracranial blood. Although methodologically easier, this approach does not account for the heterogeneity of TBI and, consequently, the spectrum of time to stabilization. To address this, our group has created an algorithm which stratifies patients by risk for spontaneous progression and tailors a unique VTE prophylaxis regimen to each arm.