A phase II trial was conducted to determine the effectiveness of weekly administration of cisplatin (25 mg/m(2) on day 1) and carboplatin (100 mg/m(2) on day 1) as salvage chemotherapy for patients with small cell lung cancer after first-line chemotherapy without platinum derivatives. Of 40 eligible patients, 38 were evaluable for response. Interval between last course of first-line chemotherapy and first course of salvage therapy was less than 3 months in 34 and greater in 4. Five partial responses (13%; confidence interval at 95%:0.01-0.25) were documented (including 4 in patients with a treatment-free interval <3 months) as well as 8 no change, 21 progressions and 4 early deaths due to malignant disease. Toxicity consisted mainly of moderate thrombopenia and leucopenia. Grade I nephrotoxicity was observed in 6 patients. In conclusion, weekly administration of moderate doses of cisplatin and carboplatin as salvage chemotherapy for small cell lung cancer appeared feasible and was associated with a moderate but definitive anticancer activity.