In order to achieve complete irrigation, reduce air in the hematoma cavity, and obtain rapid reduction of the cavity without drainage, we use burr-hole evacuation of the hematoma followed by irrigation using physiologic saline solution and replacement of the hematoma with carbon dioxide (CO2) gas. We have treated 19 cases between the ages of 41 and 84. With the exception of one case with dementia of 5 years' duration, all cases were asymptomatic postoperatively. Computed tomography (CT) scans obtained immediately postoperatively showed the gas to fill the hematoma cavity, but on the following day, the gas and the hematoma cavity had nearly disappeared. There was no surgical mortality nor morbidity and there were no side effects of the CO2 gas. Recurrence was found in one case (5.3%). By filling the hematoma cavity with CO2, disappearance of the cavity is rapid and drainage is not needed. Moreover, this technique implies no restrictions on postoperative motility, and is thus suitable for elderly patients.