We assessed the efficacy of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) when administered by 3-hour intravenous infusion in 15 patients with advanced breast cancer resistant to anthracyclines. Paclitaxel was administered at 175 mg/m2. In the event of severe toxicity, dose reductions to 150 or 125 mg/m2 could be made; otherwise, the dose was subsequently increased to 200 mg/m2. Patients received a median of five cycles of treatment (range, one to nine cycles). Paclitaxel induced three complete responses and four partial responses, for an overall response rate of 47%. The most frequently observed toxicities associated with paclitaxel administration were neutropenia and alopecia, which occurred in all patients. The frequency and severity of the observed toxicities were never of clinical concern. We conclude that paclitaxel is active in breast cancer patients clinically resistant to anthracyclines and that it can be safely administered by 3-hour infusion with standard premedication. Considering the good tolerability, higher doses of paclitaxel in advanced breast cancer should be explored.