The objective of this study was to investigate the safety and efficacy of intranasal civamide for the acute treatment of migraine headache with or without aura. Civamide is a vanilloid receptor agonist and neuronal calcium channel blocker that inhibits the neuronal release of excitatory neurotransmitters (e.g. calcitonin gene-related peptide (CGRP) and substance P (SP)) and depletes the neurones of the trigeminal plexus of their neurotransmitter content. Applied intranasally, the release of neurotransmitters to meningeal and dural blood vessels should be decreased, along with the resultant vasodilatation, plasma extravasation, and histamine/serotonin release. Subsequent migraine headache pain may also be diminished. Thirty-four patients were enrolled into a double-blind study of intranasal civamide, and randomized to receive a single dose of either 20 microg or 150 microg of civamide, for the treatment of a single migraine headache, with or without aura, of moderate to severe pain. At 2 h post-dose, 55.6% of patients treated with either dose had a decrease in pain severity, with 22.2% of patients being pain-free. At 4 h post-dose, 72.7% of patients treated with either dose had a decrease in pain severity, with 33.0% of patients being pain-free. Adverse events were similar for both dosages, with 91.2% of patients experiencing nasal burning and 44.1% of patients experiencing lacrimation. No systemic side-effects were observed. Based upon the results of this study, intranasal civamide may be effective in the acute treatment of migraine headache. Given civamide's proposed mechanism of action, intranasal civamide should be substantially more effective for prophylaxis than acute treatment of migraine. A study evaluating its efficacy in prophylaxis of migraine is currently planned.