21 patients, who fulfilled the clinical and angiographic criteria of a spontaneous carotid cavernous fistula (CCF), were studied at the Alfried Krupp Hospital, Essen, Germany, between 1980 and 1988. Of these patients, 4 had direct shunts between the internal carotid artery and the cavernous sinus and 17 patients had unilateral or bilateral dural shunts between meningeal branches of the internal and/or external carotid artery and the cavernous sinus. The most common initial symptoms were eye redness, bruit and headache. 6 of 12 patients with double vision had mechanical disorders of eye movement. A rapid irreversible loss of vision occurred in 2 patients. In 9 of 21 patients either progressive visual deterioration, proptosis or severe orbital pain necessitated prompt institution of treatment. All direct fistulas could be occluded by the use of the detachable balloon technique. 5 patients with dural CCF were successfully treated with particle embolization of the external carotid artery blood supply. In dural CCF not requiring emergent treatment, combined carotid artery and jugular vein compression was preferred and resulted in complete cure or sufficient improvement in all but one patient. We recommend this method as the first stage of treatment in dural CCF with uncomplicated course.