Sodium chloride 3% is indicated for the treatment of severe hyponatremia and increased intracranial pressure, including cerebral edema associated with trauma, stroke, or neurosurgical conditions. Its key advantage is rapid osmotic effect, which draws water out of brain cells into the intravascular space, leading to reduction of cerebral edema and improvement of neurological status. In ICU and emergency settings, it provides fast and controlled correction of sodium levels, helping prevent life-threatening complications such as seizures and brain herniation. Compared to isotonic fluids, hypertonic saline offers targeted volume expansion with smaller volumes, which is beneficial in critically ill patients. Careful monitoring ensures safe and effective use, making it an essential tool in neurocritical care and emergency medicine.