A questionnaire-based study was carried out at the Department of Oncology, University Hospital of Tromsø, during the period July 1990-October 1991. The 252 participating patients received a questionnaire at arrival at the oncology unit and the surviving patients a follow-up questionnaire at home 4 months later. The aim of the study was to assess whether patients' attitudes to information about their malignant disease and satisfaction with the given treatment correlated to their use of non-proven therapies (NPTs) and reported mental distress. Patients under 45 years of age significantly more often preferred comprehensive medical information than older patients (83% versus 52%, P = 0.001). Better educated patients were more satisfied with the information given by their general practitioner (GP) (P = 0.05) and at their local hospital (P = 0.02) than other patients. Of all responders, 81% of the patients treated in the department were completely satisfied with the opportunities to ask questions while 87% reported being given comprehensive information. Only 2% of the patients reported to have received unwanted information. Better educated patients expressed less satisfaction with the information given and the possibility of influencing their own treatment at the Department of Oncology (P = 0.02). Patients expressing mental distress wanted less information (P = 0.05) and expressed less satisfaction with the quality of the perceived information in the oncology unit (P = 0.004). They were also less satisfied with the treatment given (P = 0.05) and their own influence on the treatment decision (P = 0.02). Users of NPT did not feel the received treatment to be the best possible (P = 0.04).