Published double-blind studies of the effectiveness of Ca2+ entry blockers in migraine prophylaxis are critically reviewed. The evidence in case of flunarizine is satisfactory, and the drug exerts few and minor side effects. Nimodipine also seems to be effective, but the evidence is not quite satisfactory. The interpretation of two studies with verapamil is hampered by serious methodological problems, and the evidence is clearly insufficient to recommend the use of verapamil in migraine prophylaxis. Mechanisms of action are understandable in classic migraine, but still completely unknown in common migraine. Ca2+ entry blockers open up new and fascinating aspects of migraine research.