Migraine patients who experience an average of 2 or more attacks per month are eligible for preventive treatment as well as treatment for acute attacks. The decision to offer preventative treatment is also made on the basis of the average attack duration, severity of the attacks, and response to attack treatment. Prior to initiating preventive treatment, the average attack frequency per month should be assessed, preferably by means of a headache diary over a number of months, as attack frequency is extremely variable. None of the currently available preventive drugs, such as beta-blockers, sodium valproate, topiramate and candesartan, were developed specifically for treating migraine, but were all originally intended for other indications. 50% of the migraine patients receiving preventive treatment can expect a 50% reduction in attacks, and the remaining attacks often seem to be less severe. The effects of the drugs are often unpredictable per individual, and side-effects frequently lead to early discontinuation of treatment. Drugs usually prescribed for cardiovascular disorders are often used. In the case of a disorder such as migraine with a high burden of disability, patients with cardiovascular or pulmonary comorbidity should receive medication that is optimally adjusted for both indications.