Six phase II studies have been conducted in the United States and Europe using docetaxel (Taxotere; Rhone-Poulenc Rorer, Antony, France) for advanced non-small cell lung cancer. One hundred eighty chemotherapy-naive patients in four studies and 88 patients who failed prior platinum-containing chemotherapy in two studies were treated with docetaxel 75 to 100 mg/m2 intravenously over 1 hour every 3 weeks. Fifty-nine percent of patients had adenocarcinoma and 82% had stage IV disease. At a dose of 100 mg/m2, 30% of evaluable chemotherapy-naive patients (27% of the intent-to-treat population) and 20% of evaluable platinum-refractory/resistant patients (17% of the intent-to-treat population) achieved a partial response; projected median survival is 9 months in both studies. Neutropenia was the primary dose-limiting acute side effect. Fluid retention, which occurred in patients who received multiple courses of treatment, was common but rarely dose-limiting, and may be ameliorated with prophylactic corticosteroids. Other toxic effects were relatively mild. Docetaxel has significant activity against advanced non-small cell lung cancer, producing a major response in both chemotherapy-naive patients and patients who had failed prior platinum-containing chemotherapy.