5-Fluorouracil plus folinic acid and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) are effective salvage therapies for metastatic breast cancer patients. Paclitaxel and 5-fluorouracil have additive cytotoxicity in MCF-7 cell lines. We performed a phase II trial of paclitaxel 175 mg/m2 over 3 hours on day I followed by folinic acid 300 mg over 1 hour before 5-fluorouracil 350 mg/m2 on days 1 to 3 every 28 days (TFL) in women with metastatic breast cancer. Analysis is reported on 37 patients with a minimum of 6 months follow-up who received a total of 192 cycles of TFL: nine cycles (5%) were associated with grade 3/4 neutropenia requiring hospitalization; seven (4%) cycles in two patients required granulocyte colony-stimulating factor due to neutropenia; no patient required platelet transfusions. Grade 3/4 nonhematologic toxicities were uncommon. Among the 34 patients evaluable for response, there were three complete responses (9%) and 18 partial responses (53%) for an overall response rate of 62%. Of the 19 evaluable patients with prior doxorubicin exposure, 11 (58%) responded compared with nine of 15 (60%) without prior doxorubicin. Plasma paclitaxel concentrations were measured at the completion of paclitaxel infusion and at 24 hours in 19 patients. TFL is an active, well-tolerated regimen in metastatic breast cancer.