These are the first prospective studies to use criteria for menstrual migraine proposed in the 2004 revision of the International Classification of Headache Disorders (ICHD-II) to examine the efficacy of rizatriptan for treatment of a menstrual attack. Two identical protocols (MM1 and MM2) were randomized, parallel, placebo-controlled, double-blind studies. Adult women with ICHD-II menstrual migraine were assigned to either rizatriptan 10-mg tablet or placebo in a 2 : 1 ratio. Patients treated a single menstrual migraine attack of moderate or severe pain intensity. The primary end-point was 2-h pain relief and the secondary end-point was 24-h sustained pain relief. A total of 707 patients (MM1 357, MM2 350) treated a menstrual migraine attack. The percentage of patients reporting 2-h pain relief was significantly greater for rizatriptan than for placebo (MM1 70% vs. 53%, MM2 73% vs. 50%), as was the percentage of patients reporting 24-h sustained pain relief (MM1 46% vs. 33%; MM2 46% vs. 33%). Rizatriptan 10 mg was effective for the treatment of ICHD-II menstrual migraine, as measured by 2-h pain relief and 24-h sustained pain relief.