The differential diagnosis of headache is broad, ranging from immediately life-threatening to benign etiologies. Currently, headaches can be treated successfully with various nonnarcotic analgesics. Three cases are presented in which patients with headaches were treated in an emergency department with nonnarcotic analgesics which relieved their headaches; subsequently, these patients returned to be diagnosed with intracranial hemorrhage. Some nonnarcotic analgesics may relieve symptoms of intracranial hemorrhage through their recognized mechanisms of action. Avoiding such occurrences requires that the diagnosis of headache be made with careful consideration of the patient's history. A patient presenting with a new onset of severe headache or a headache that is different from those experienced in the past deserves a thorough diagnostic work-up including a computed tomography scan followed by lumbar puncture if indicated. Diagnostic decisions regarding headache should not be based on a patient's response to any analgesic, nonnarcotic or narcotic.