4'-Deoxydoxorubicin was administered to 27 evaluable patients with refractory small cell lung cancer. The majority of patients had good initial performance status. One third of patients had never received doxorubicin before, and six had received a single drug alone (VM26). Myelotoxicity was the main side-effect, and leukopenia was more pronounced than thrombocytopenia. No significant non-hematological toxicity occurred apart from skin necrosis due to drug extravasation in one case. Two patients had partial response (7.4%; 95% confidence limits 0-17.2%). The low response rate obtained in this good prognosis patient population does not support further testing of this drug in small cell lung cancer.