Brain sag is a rare but serious postoperative complication after craniotomy. It is a clinical entity that refers to severe cerebrospinal fluid hypovolemia causing acute neurologic decompensation and obtundation. The established treatment is trendelenberg positioning. We present 3 cases of severe brain sag in which patients developed acute neurologic deterioration unresponsive to conventional treatment. An epidural blood patch was performed emergently to prevent further neurologic decline. The administration of epidural blood patch resulted in immediate and dramatic reversal of obtundation in each of these patients. Epidural blood patch may be a life-saving intervention in postcraniotomy patients presenting with refractory brain sag. It should be offered in patients who meet the criteria for brain sag and are unresponsive to conventional treatment modalities, despite the clinical presentation of herniation and coma.