4'Demethoxydaunorubicin, an orally active daunorubicin analogue, was administered to 22 patients with inoperable non small cell lung cancer (NSCLC). Patients were stratified into good and poor risk categories and received doses of 45 mg/m2 and 40 mg/m2 respectively at 28 day intervals. All 22 patients were evaluable for response: No tumour responses occurred. Therapy was well tolerated. Mild gastrointestinal toxicity occurred in 41% of patients. Leucopenia with a wcc less than 3 x 10(9)/L occurred in 33% of patients and thrombocytopenia less than 100 x 10(9)/L in 9%. Severe marrow toxicity was rare and there appeared to be no difference in terms of toxicity between the different dose levels. DMDR appears to have no useful clinical activity in NSCLC.