Understanding the self-prescribing behaviours of patients as well as their attitudes towards prescribed medication regimens is essential if healthcare professionals are to support treatment adherence and avoid unwanted pharmacological interactions and compromises in treatment efficacy. Evidence shows that women with breast cancer are particularly likely to use complementary and alternative therapies. This paper describes the reported treatment profile of a sample of 208 women with breast cancer in the UK. The information was gathered as part of a study exploring the preferences for injection or tablets in the administration of breast cancer treatment. Almost two-thirds of the sample were currently taking prescribed breast cancer treatment, mostly a single hormone therapy. Prescribed medications for co-morbid diseases were also common, and 53% of the women were self-medicating mainly with supplements, principally vitamins, various oils and minerals. In line with other studies, higher levels of education, socio-economic status and internal locus of control were associated with non-prescription use as well as a body mass index <30.