Alongside objective response rate, quality of life of patients is important in the treatment of cancer, particularly in the palliative setting. Quality of life is difficult to define precisely and is correspondingly difficult to assess. However, a number of methods have been devised and self-report questionnaires are now widely used. Patients with metastatic non-small cell lung cancer (NSCLC) have a poor prognosis with few patients surviving longer than 8 or 9 months. Curative treatment is often not possible and few patients receive active treatment. Although some patients will accept toxic treatments in return for increased survival, it is generally hoped that any treatment, curative or palliative, will not adversely affect patients' quality of life. In three studies in which gemcitabine was used as a single agent in metastatic NSCLC, objective response rates of 20% were obtained. Gemcitabine was well tolerated. Symptoms improved in the studies where disease-related symptoms were assessed. The degree of improvement compared well with historical data on the relief offered by standard radiotherapy and combination chemotherapy. These findings have led to the initiation of a randomised trial to compare the relief offered by gemcitabine plus best supportive care with best supportive care, using quality of life assessments as a primary endpoint.