An 8-month, double-blind, placebo-controlled crossover trial was carried out on the use of nimodipine in migraine prophylaxis in 37 patients aged 7 to 18 years old. After a 4-week medication-free run-in period, 19 subjects (Group 1) received a placebo while 18 (Group 2) received nimodipine (10-20 mg t.i.d., according to body weight), for 12 weeks. After a 4-week wash-out period, the groups switched therapy for a further 12 weeks. 30 patients completed the trial and the number of dropouts was comparable in the 2 groups. The only side-effect during nimodipine treatment was mild abdominal discomfort (3 cases). The treatments were evaluated on the basis of frequency and duration of attacks. There was a significant reduction in both parameters during the first period of treatment. During the second period of treatment, nimodipine proved to have a significantly greater effect than the placebo with regard to frequency, whereas the response was similar with the placebo as regards duration of attacks. The latter parameter shows a significant decrease during the treatment periods, regardless of type of therapy.