The purpose of the study was to determine the efficacy and safety of docetaxel plus continuous infusion of 5-fluorouracil (5-FU) in patients with metastatic breast cancer previously treated with anthracyclines. A total of 41 patients with histologically proven metastatic breast cancer and performance status 0-2, who had received at least one anthracycline-containing regimen, received docetaxel 85 mg m(-2) followed by continuous infusion of 5-FU 750 mg m(-2) day(-1) for 5 days every 3 weeks for up to eight cycles. All patients received corticosteroid premedication, but there was no prophylactic colony-stimulating factor support. The most frequent metastatic sites were the liver (61%), bone (29%), and lung (29%). All 41 patients were assessable for toxicity and 30 were eligible and assessable for efficacy. The objective response rate was 70.0% (95% CI: 53.6-86.4%) for the per protocol group and 53.7% (95% CI: 38.4-68.9%) for the intent-to-treat (ITT) population. For the ITT population, median duration of response was 8.4 months (95% CI: 6.7-12.2 months), median time to progression was 6.7 months (95% CI 5.5-8.6 months), and median survival was 17 months (95% CI: 12.3-not recorded months). Grade 3/4 neutropenia occurred in 54% of patients, with febrile neutropenia in 24% of patients and 5% of cycles, but infections were rare. Stomatitis was frequent, grade 3 in 24% of patients and grade 4 in one patient (2%), but manageable. Diarrhoea was rare, grade 3 in 7% of patients and 1% of cycles. Other grade 3/4 nonhaematological toxicities were infrequent. In conclusion, this docetaxel/5-FU regimen is highly active and well tolerated in patients with anthracycline-pretreated metastatic breast cancer. The efficacy is particularly promising, as one-third of patients were either second-line and/or anthracycline-resistant/refractory.