The use of complementary and alternative medicine (CAM) in migraine is a growing phenomenon about which little is known. This study was undertaken to evaluate the rates, pattern and presence of predictors of CAM use in a clinical population of patients with different migraine subtypes. Four hundred and eighty-one migraineurs attending a headache clinic were asked to undergo a physician-administered structured interview designed to gather information on CAM use. Past use of CAM therapies was reported by 31.4% of the patients surveyed, with 17.1% having used CAM in the previous year. CAM therapies were perceived as beneficial by 39.5% of the patients who had used them. A significantly higher proportion of transformed migraine patients reported CAM treatments as ineffective compared with patients suffering from episodic migraine (73.1% vs. 50.7%, P < 0.001). The most common source of a recommendation of CAM was a friend or relative (52.7%). In most cases, migraineurs' recourse to CAM treatments was specifically for their headache (89.3%). Approximately 61% of CAM users had not informed their medical doctors of their CAM use. The most common reason for deciding to try a CAM therapy was that it offered a 'potential improvement of headache' (47.7%). The greatest users of CAM treatments were: patients with a diagnosis of transformed migraine; those who had consulted a high number of specialists and reported a higher lifetime number of conventional medical visits; those with a comorbid psychiatric disorder; those with a high income; and those whose headache had been either misdiagnosed or not diagnosed at all. Our findings suggest that headache clinic migraine patients, in their need of and quest for care, seek and explore both conventional and CAM approaches. Physicians should be made aware of this patient-driven change in the medical climate in order to prevent misuse of healthcare resources and to be better equipped to meet patients' needs.