The study drug envelope was labeled ‘placebo’ (2 attacks), ‘Maxalt or placebo’ (2 attacks) or ‘Maxalt’ (2 attacks), in order to provide negative, neutral or positive information, respectively. Subjects were instructed to open the envelope and swallow the pill 30 min after onset of headache. They were asked to refrain from taking rescue medications during the first 2.5 h of each attack, including untreated attack (control).