Six previously untreated poor prognosis patients and eight previously treated patients with small cell lung cancer (SCC) were treated with 1,2,4-triglycidylurazol (TGU, NSC-332488) 800 and 650 mg/m2 every 4 weeks, respectively. No responses were observed. The survival time of the previously untreated patients was short, a median of 7 weeks (range 5-10 weeks). Myelosuppression was severe and prolonged with white blood count, WHO grade 3-4, in four previously untreated patients and in two previously patients, and with platelets, WHO grade 3-4, in both four previously untreated and in four previously treated patients. Gastrointestinal toxicity was mild to moderate. It is concluded that TGU is inactive in SCC.