BMS180048 is a 5HT agonist that was well-tolerated in early phase II trials. This study utilized a double-blind, parallel-group dose ranging format, comparing BMS180048 in doses of 25, 50, or 75 mg to placebo in effectiveness of treatment of a single migraine headache. To assess tolerability of BMS180048, patients received a test dose of the medication they would receive for a headache in the clinic under observation. If no significant side effects occurred, patients were allowed to treat a headache. Headaches were moderate or severe in intensity before treatment, and response at 2 hours was tabulated. Reduction to mild or no headache was the criteria for successful response. Response rates at 2 hours were as follows: placebo--19 of 53 subjects (35.8%); 25 mg--21 of 53 subjects (40.3%); 50 mg--34 of 53 subjects (64.2%); 75 mg--35 of 55 subjects (63.6%) The improvement for subjects treated with 50 or 75 mg of BMS180048 when compared to placebo was highly significant (P < .01). Nausea, photophobia, and phonophobia improved 35% to 50% for BMS180048-treated subjects and 20% to 24% in the placebo group. The improvement in these symptoms in comparison to placebo was statistically significant only for nausea in those treated with 75 mg of BMS180048 (P = .02). Side effects were mild for the most part, and no serious adverse events occurred. The study suggests BMS180048 is effective in acute symptomatic therapy of migraine.