BACKGROUND: Polycystic ovary syndrome (PCOS) is a complex reproductive endocrinopathy affecting up to 20% of reproductive aged women. Whilst there are effective pharmaceutical treatment options, women with PCOS have expressed a strong desire for alternatives. This study investigates the use and attitudes of women with PCOS towards complementary medicine (CM). METHODS: Women as members of PCOS support groups responded to an anonymous on-line survey which examined rates and patterns of use for CM's, areas of health for use, perceptions of effectiveness, safety and demographic features. Data collection targeted women with PCOS using two consumer support groups. The first group self-selected following direct email to members of a land based consumer support group, the Polycystic Ovary Syndrome Association of Australia (POSAA). The second sample was generated through the electronic social network Facebook, using a snowball technique. Two surveys, identical in content, were collected by cloud based Survey Monkey. Data were described and associations between the variables, 'reasons for use' and 'perceptions of effectiveness' were explored. Non-response bias was assessed using a continuum of resistance model. RESULTS: 493 women participated in the study; 91.1% response rate from the POSAA group. Over 70% reported use of complementary medicine, usually nutritional and herbal supplements and 76.6% of CM users reported consultation with a complementary practitioner. Many participants were using CM to treat PCOS however most were using it to concurrently treat a range of health conditions, describing women's desire for more than single symptom management. Disadvantages for CM use were cited by 71% of respondents. Women using complementary medicine with specific treatment goals in mind reported greater self-perceived effectiveness, suggesting that informed use may improve women's satisfaction with CM. Adverse reactions were reported by 12.2% of women and the need for further research into adverse reactions for CM's was identified. Demographic and PCOS characteristics were similar to clinical populations of PCOS and non-response bias was shown as not significant. CONCLUSION: This study describes the prevalence of use for complementary medicine by women with PCOS as over 70% and adds to our understanding of women's experiences with CM and their motivations for use of CM.