Oral contraceptive-induced menstrual migraine (OCMM) is a poorly defined migraine subtype mainly triggered by the cyclic pill suspension. In this pilot, open-label trial we describe its clinical features and evaluate the efficacy of frovatriptan in the treatment of its acute attack. During the first 3 months of the study 20 women (mean age 32.2+/-7.0, range 22-46) with a 6-month history of pure OCMM recorded, in monthly diary cards, clinical information about their migraine. During the 4th menstrual cycle they treated an OCMM attack with frovatriptan 2.5 mg. The majority of attacks were moderate/severe and lasted 25-72 h or more, in the presence of usual treatment. Generally an OCMM attack appeared within the first 5 days after the pill suspension, but in 15% of cases it started later. After frovatriptan administration, headache intensity progressively decreased (2.4 at onset, 1.6 after 2 h, 1.1 after 4 h and 0.8 after 24 h; p=0.0001). In 55% of patients pain relief was reported after 2 h. Ten percent of subjects were pain-free subjects after 2 h, 35% after 4 h and 60% after 24 h (p=0.003 for trend); 36% relapsed within 24 h. Rescue medication was needed by 35% of patients; 50% of frovatriptan-treated required a second dose. Concomitant nausea and/or vomiting, photophobia and phonophobia decreased significantly after drug intake. OCMM is a severe form of migraine; actually its clinical features are not always exactly identified by the ICHD-II classification. However, treatment with frovatriptan 2.5 mg might be effective in its management.