Sumatriptan succinate, a serotonin-1 (5-hydroxytryptamine-1) receptor agonist, is an antimigraine drug that is reported to act by selectively constricting intracranial arteries. Recently, vasopressor responses that are distinct from the cranial circulation have been demonstrated to occur in the systemic, pulmonary, and coronary circulations. Cases have been published of coronary vasospasm, myocardial ischemia, and myocardial infarction occurring after sumatriptan use. We report on the development of 8 serious cases of ischemic colitis in patients with migraine treated with sumatriptan.