Butterbur supports healthy blood vessel tone and circulation in the brain. This herb can both prevent and eliminate migraines. Take 50 mg 3 times a day for 1 month and then 50 mg twice a day to prevent migraines. You can take 100 mg every 3 hours to eliminate an acute migraine. Use only high quality brands. Many brands have been tested and demonstrated to contain impurities and don't contain the amount of butterbur the label claims and, therefore, don't work.