Results from two phase II studies in metastatic breast cancer have shown that the novel, tumour-selective fluoropyrimidine capecitabine provides an effective and well tolerated therapy in patients with metastatic breast cancer failing or resistant to anthracycline and taxane therapy. Response rates of between 20 and 25% have been observed, with median survival of 12.2-12.6 months. In addition, there was an acceptable incidence of adverse events including diarrhoea and hand-foot syndrome, which can be controlled with a dose reduction. Promising results from two further randomised, phase II studies have indicated that capecitabine may also play a role in first- and second-line treatment of metastatic breast cancer. Capecitabine compared favourably with paclitaxel in anthracycline-resistant patients and with intravenous (i.v.) CMF (cyclophosphamide/methotrexate/5-fluorouracil (5-FU)) in post-menopausal women who had received no prior chemotherapy for metastatic disease, with high efficacy and good tolerability. The results of these four phase II studies demonstrate that capecitabine is active and well tolerated in a range of settings for metastatic breast cancer.