Quality of life evaluations can enhance traditional measures of therapeutic efficacy. The purpose of our study was to evaluate the impact of sumatriptan on the quality of life of patients with migraine headaches. Migraine patients who were given a prescription for sumatriptan completed an SF-36 questionnaire and a nine-item pain questionnaire. Six to 9 months later, patients were mailed another copy of the SF-36 and the nine-item pain questionnaire. We compared the pretreatment and posttreatment scores for the SF-36 and for each question of the nine-item pain questionnaire. The pretreatment SF-36 was completed by 255 patients. The pretreatment pain questionnaire was completed by 86 of these patients. Follow-up questionnaires were returned by 147 patients (58%). Three of the eight SF-36 scales: role functioning--physical, bodily pain, and social functioning showed significant (P < 0.05) improvement with treatment. On the nine-item pain-specific questionnaire, three items--pain interference with normal work, ability to walk or move about, and enjoyment of life showed statistically significant (P < 0.05) improvement after sumatriptan treatment. Sumatriptan caused a significant improvement in the quality of life of patients with very severe migraine. This improvement was measurable by both the general quality of life instrument and the pain-specific questionnaire.