The efficacy and tolerability of subcutaneous (SC) sumatriptan administered with the IMITREX (sumatriptan succinate) STATdose System, which circumvents the need for patients or health care professionals to handle a syringe, were evaluated in two randomized, double-masked, parallel-group, placebo-controlled, multicenter studies. In the clinic, 158 adults with migraine diagnosed according to International Headache Society criteria received SC sumatriptan (6 mg) or placebo delivered with the IMITREX STATdose System for treatment of a migraine attack. By 120 minutes after SC dosing, 73% and 79% of sumatriptan-treated patients, compared with 28% and 37% of placebo-treated patients in studies 1 and 2, respectively, experienced headache relief (a statistically significant difference). Clinical disability scores 120 minutes after dosing showed that 75% and 85% of sumatriptan-treated patients, compared with 30% and 42% of placebo-treated patients, were normal or only mildly impaired (a statistically significant difference). Similar efficacy rates were observed for nausea, phonophobia, and photophobia. No serious or unusual adverse events occurred, and no clinically relevant abnormalities in laboratory test values were reported. Based on these results, we concluded that SC sumatriptan (6 mg) administered using the IMITREX STATdose System is effective for the treatment of migraine. The efficacy and tolerability profiles of SC sumatriptan administered with this device are similar to those reported for SC sumatriptan administered with a conventional syringe.