BACKGROUND Non-medical, non-pharmacological and pharmacological treatments are recommended for the prevention of migraine. The purpose of this randomized double-blind placebo controlled, multicenter trial was to evaluate the efficacy of a proprietary nutritional supplement containing a fixed combination of magnesium, riboflavin and Q10 as prophylactic treatment for migraine. METHODS 130 adult migraineurs (age 18 - 65 years) with ≥ three migraine attacks per month were randomized into two treatment groups: dietary supplementation or placebo in a double-blind fashion. The treatment period was 3 months following a 4 week baseline period without prophylactic treatment. Patients were assessed before randomization and at the end of the 3-month-treatment-phase for days with migraine, migraine pain, burden of disease (HIT-6) and subjective evaluation of efficacy. RESULTS Migraine days per month declined from 6.2 days during the baseline period to 4.4 days at the end of the treatment with the supplement and from 6.2.days to 5.2 days in the placebo group (p = 0.23 compared to placebo). The intensity of migraine pain was significantly reduced in the supplement group compared to placebo (p = 0.03). The sum score of the HIT-6 questionnaire was reduced by 4.8 points from 61.9 to 57.1 compared to 2 points in the placebo-group (p = 0.01). The evaluation of efficacy by the patient was better in the supplementation group compared to placebo (p = 0.01). CONCLUSIONS Treatment with a proprietary supplement containing magnesium, riboflavin and Q10 (Migravent® in Germany, Dolovent® in USA) had an impact on migraine frequency which showed a trend towards statistical significance. Migraine symptoms and burden of disease, however, were statistically significantly reduced compared to placebo in patients with migraine attacks.