Data on liquorrhoea in cases collected in 1947-1977 at the Department of Neurosurgery, University Hospital of Lund, Sweden, are analysed with reference to: 1. Time of onset. 2. Symptoms and signs. 3. Diagnostic methods. 4. Treatment-conservative and surgical. 5. Antibiotic prophylaxis. In more than half of the 66 patients the onset of liquorrhoea was delayed more than one month after the head trauma. Antibiotic prophylaxis to all skull base fractures therefore is questioned. False positive reaction with locally applied test strips is noted. Gammacisternography for localization of the leaking area is recommended. If surgery is performed, a high rate of recurrence can be expected if the supposed leaking area is blindly covered.