Blood in the urine may be either microscopic or macroscopic, the latter generally causing patients to come to the emergency department. In patients who present with “blood in the urine,” artifactual causes must be considered and excluded. These include hemoglobinuria, myoglobinuria, beet ingestion, and the use of phenolphthalein-containing laxatives. Although significant blood loss is unusual except in patients with bleeding secondary to trauma or anticoagulation, as in any patient with blood loss, hemodynamic stability should be evaluated early and corrected as needed.