This trial was initiated to evaluate the toxicity and activity of combination chemotherapy employing cisplatin (CDDP), docetaxel (DCT) and ifosfamide (IFX) in non-small cell lung cancer (NSCLC), and to determine the maximum tolerated dose (MTD) of IFX. Chemotherapy-naive patients with advanced or recurrent NSCLC received 60 mg/m(2) DCT followed after a 3-h interval by 60 mg/m(2) CDDP on chemotherapy day 1, and IFX at an escalating dose with mesna protection on days 2-4. The chemotherapy was repeated every 3 weeks. Granulocyte colony-stimulating factor (GCSF) was administered in the event of grade 3 leukopenia/neutropenia. The patients tolerated the treatment well up to level 4 of IFX dosing 1.5 g/day, but not the IFX dose at level 6 (2.0 g/day). Additional patients were enrolled in level 5 (IFX 1.7 g/day) to evaluate the toxicity of the drugs around the MTD. Level 5 was also judged as having exceeded the MTD, with febrile neutropenia and hepatic toxicity being observed as the dose-limiting toxicities. No toxicity-related deaths occurred. The majority of the chemotherapy courses were supported by GCSF administration. A total of 33 eligible patients were entered into the trial; the overall response rate was 10/33 or 30% among all eligible cases, and the rate for patients treated with the MTD or higher (levels 4-6) was 8/24, or 33% (90% confidence limit: 18-52%). The MTD of IFX was 1.5 g/m(2) administered for 3 days in this triplet combination. The clinical activity does not seem to justify the toxicity profile.