The possibility of using etoposide 25 mg daily as adjuvant chemotherapy for non-small cell lung cancer was discussed. Initially, 73 patients who had undergone resection participated in this trial; 49 of them were eligible, 24 including a patient over 70 years of age (8) took the drug for 1 year, 22 patients resigned from the study due to side effects, and a further 3 patients died during the trial. The main side effects observed were gastro-intestinal trouble (13) and pneumonia (4). The side effects of this drug appeared early in the treatment phase. During the first month of treatment, 9 patients discontinued the drug due to side effects, and 10 more did so within 4 months. To achieve optimal conditions for the trial study of low-dose etoposide it was found important to select patients under 70 years of age and to control side effects of the drug on the gastro-intestinal tract from the beginning.