Migraine headaches impart substantial personal and financial costs on individuals, health systems, and employers. We have known for nearly two decades that one-tenth or more of the population suffers from migraines in a given year. For persons experiencing migraines, multiple episodes consume an average of more than 2 weeks per year. For health systems, persons with migraines use significantly more physician services and pharmaceutical services than persons without migraines. For employers, missed days of work, or absenteeism, and reduced productivity at work, presenteeism, cost one-half percent of total labor productivity, a figure that translates to one-tenth of net corporate profits in 2000. Clearly, the appropriate treatment of migraines is a substantial societal concern.