For women who have oestrogen and/or progesterone receptor-positive breast cancer, hormone treatment may be the longest continuous treatment they receive for their disease. Oral tamoxifen has been the ‘gold standard’ for many years, but recent research raised questions about how newer anti-oestrogen drugs, such as aromatase inhibitors, may be used to benefit breast cancer patients. This article looks at the range of hormone treatments currently available and examines the rationale behind their use, in order that nurses working in the field of oncology might better be able to explain treatment options and side effect profiles to their patients.