Warfarin is a recognized high-risk medication that accounts for many hospitalizations due to adverse drug events. This case-control study of patients with traumatic brain injury found that hospital length of stay and mortality were higher among patients taking warfarin compared to those who were not. Additionally, more than 16% of the patients on warfarin may have been taking the medication inappropriately. A WebM&M commentary discusses a case involving a near miss due to inadequate warfarin monitoring.