Emergency medicine practitioners treat bleeding patients on a regular basis. Disorders of hemostasis are an additional challenge in these patients but can be assessed and managed in a systematic fashion. Of particular importance to the emergency clinician are the iatrogenic causes of abnormal hemostasis. Other acquired causes of abnormal hemostasis include renal disease, immune thrombocytopenia, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, acquired coagulation factor inhibitors, acute traumatic coagulopathy, liver disease, and disseminated intravascular coagulopathy.