Over 250 patients from three complementary medicine practices-acupuncture, osteopathy and homoeopathy-completed a questionnaire rating 20 potential reasons for seeking complementary treatment. The reasons that were most strongly endorsed were "because I value the emphasis on treating the whole person'; "because I believe complementary therapy will be more effective for my problem than orthodox medicine'; "because I believe that complementary medicine will enable me to take a more active part in maintaining my health'; and "because orthodox treatment was not effective for my particular problem'. Five factors were identified, in order of importance: a positive valuation of complementary treatment, the ineffectiveness of orthodox treatment for their complaint, concern about the adverse effects of orthodox medicine, concerns about communication with doctors and, of less importance, the availability of complementary medicine. Groups were compared, using analysis of covariance to control for demographic differences between the three patient groups. Osteopathy patients' reasons indicated they were least concerned about the side effects of orthodox medicine and most influenced by the availability of osteopathy for their complaints. Homoeopathy patients were most strongly influenced by the ineffectiveness of orthodox medicine for their complaints, a fact which was largely accounted for by the chronicity of their complaints. Results are discussed in terms of the limited research in this area. Future studies should separate the reasons for beginning complementary treatment from the reasons for continuing it. It is possible, for instance, that the failure of orthodox medicine is the strongest motive for seeking complementary treatment but that, once treatment has been experienced, other more positive factors become more important.