The antitumoral activity and toxicity of a new daunorubicin analog (4-demethoxydaunorubicin, IMI 30, Idarubicin) was tested in 20 consecutive patients with non-small cell lung cancer mostly pretreated with chemotherapy. The drug was administered orally at a dose of 15 mg/m2 for three days every 3-4 weeks. There were no clinical responses. Hematological and nonhematological toxicities were mild.