Cisplatin (CDDP) and etoposide are synergistic in vitro: the aim of this study was to evaluate the efficacy of a continuous infusion (C.I.) of these 2 drugs in inoperable non-small cell lung cancer. Patients were to receive 3 courses of CDDP 20 mg/m2/d in 1 l saline x 5d and etoposide 50 mg/m2/d in 21 saline x 5d--both in C.I.--every 3-4 weeks. Thirty patients have entered the study. Four were inevaluable for response. One patient got complete remission, 15 partial remission, 8 no change and 2 progressive disease. The response rate was 53.3% overall (95% confidence interval: 35-71%), and 61.5% for 26 assessable patients. Toxicity appeared to be acceptable despite 52% transient neutropenia--one patient died during aplasia--and 78% grade 1 to 3 nausea or vomiting. Treatment was stopped in only one case, and modified in 6 others. The high response rate that we observed, supports the idea of potentiation of the antineoplastic effect of CDDP and etoposide by C.I., in non-small cell lung cancer. These results must be confirmed in larger series before definitive conclusions can be drawn.