A double-blind, double-dummy clinical trial was conducted in which the efficacy of cyclandelate 1600 mg daily was compared with that of flunarizine 10mg daily in 40 patients (25 men and 15 women) with dementia of cerebrovascular origin. Parameters were assessed before treatment, and after 45 and 90 days of therapy. At 90 days, significant improvements were observed in patients given cyclandelate in measurements of P100 latency in the left eye, neurological impairment, dementia scores, ischaemia scores, Gottfries mental deterioration scale, Hamilton depression scores, short term visual memory, long term memory, Bender-Gestalt test and Koh's blocks test. In flunarizine recipients, improvements were observed in neurological impairment, ischaemia scores, Gottfries scale and Hamilton depression scores. Patients treated with cyclandelate showed significantly greater ameliorations in symptoms as assessed by the ischaemia scale, evoked visual potential, visual memory and Koh's block test compared with those given flunarizine. However, in none of the parameters was flunarizine superior to cyclandelate.