Background: Cluster headache belongs to a group of idiopathic headache entities, the trigeminal autonomic cephalalgias (TACs), all of which involve short-lasting, unilateral, severe headache attacks and typical accompanying autonomic symptoms. The life-time prevalence of cluster headache for adults of all ages is around 125/100,000, or approximately 0.1%, with clear male dominance (4:1). Prophylactic treatment is an important part of the total management of cluster headache patients, having twofold goals: i) to reduce the frequency, painfulness, and/or duration of headache attacks, and ii) to increase the effectiveness of abortive therapy. During the past several decades, a large number of optional modalities have been tested as preventive measures of cluster headache. Not unexpectedly, the effects of any such preventive therapies are highly variable, and in many patients, the attack frequency is not under satisfactory control. Many of these drugs also have untoward side effects that offset their potential benefits.