89 Background: Breast cancer patients are particularly susceptible to marketing strategies employed to encourage the use of natural supplements and natural therapies. Supplements/natural therapies are freely available from various sources, including online commercial sites, therefore making them readily accessible and poorly regulated. Methods: An anonymous questionnaire on supplement use was distributed to patients diagnosed with breast cancer. Fifty-one questionnaires were completed and data was collected into a REDCapTM based database and subsequently analysed. Results: Thirty-two patients (62.7%) were using supplements prior to their diagnosis. Thirty-two (62.7%) patients did not think supplements had harmful side effects and thirty (58.8%) patients did not think they could interfere with their cancer treatment. Thirty-five patients (68.6%) would however stop their supplements if they were informed of possible interactions. Thirty-eight (74.5%) patients would prefer if their doctor informed them of potential interactions and side effects. Conclusions: Supplement use is common in breast cancer patients. The majority of patients did not believe that supplements could interfere with conventional breast cancer treatments, but the majority of patients are willing to stop the supplements if they are informed of potential interactions. Patients would prefer their doctor to inform them on supplement use. A further study is warranted to assess doctors’ knowledge around supplement side-effects and interactions.