We conducted a phase II study of docetaxel and gemcitabine chemotherapy in patients with non-small-cell lung cancer (NSCLC) who had not responded to previous chemotherapy, to assess the response to and toxicity of this combination chemotherapy. Thirty-six patients were enrolled from June 1999 to December 1999. Treatment consisted of docetaxel 30 mg/m(2) and gemcitabine 800 mg/m(2) intravenous infusion on days 1 and 8 every 3 weeks. One hundred forty-six cycles of treatment were given, with a median of four cycles (range, 1-8 cycles). All patients were evaluable for toxicity profile and response rate. The major toxicity was myelosuppression. Grade III or IV neutropenia occurred in 9 patients (25%) during treatment. Febrile neutropenia occurred in 2 patients (5.6%). Grade III or IV thrombocytopenia occurred in 6 patients (16.7%). Reversible fluid retention occurred in 9 patients (25%). Grade IV pulmonary toxicity (interstitial pneumonitis) occurred in two patients, and both died. Other toxicities were few and mild in severity. After two cycles of treatment, 13 patients (36.1%) had a partial response (95% CI 20.3-51.9%). There was no significant difference in the response rate among patients who had responded to previous chemotherapy or not. The median time to disease progression was 3.8 months, and the median survival was 6.9 months. Median survival was 7.1 and 4.9 months in patients receiving docetaxel and gemcitabine as second-line and greater than or equal to third-line chemotherapy, respectively. In conclusion, docetaxel and gemcitabine salvage chemotherapy produces a high response rate and a relatively mild toxicity profile in NSCLC. However, the issue of interstitial pneumonitis should be of concern.