BACKGROUND To date, little is known about self-help activities including the acquisition and distribution of information among brain tumour patients and their relatives. The aim of our study was to elucidate patient characteristics, methods of networking and the impact on further treatment. METHODS A German questionnaire was distributed at nationwide patient meetings and via internet forums. It was returned electronically or by regular mail. RESULTS Mean age of the 129 patients was 43.2 years. Mean age of the 140 relatives (94% family members) answering the questionnaire was 42.6 years. 51% of the patients and 60% of the relatives had a university degree. 61% of the patients suffered from high-grade tumours, and 80% of the relatives were caring for high-grade tumour patients. The higher the grade of the tumour, the earlier self-help was begun after diagnosis. The majority of the patients (36%) and their relatives (54%) spent between 1-4 h per week on self-help activities. More than 80% used the internet, but more than 85% used print products for the acquisition of information. More than 50% felt that they were not given enough information by their treating physician. Motives for self-help were the acquisition of "independent" information and psychological relief from an exchange with other tumour patients. The vast majority was satisfied with the results obtained, and more than four out of five who responded to the questionnaire exchanged information with other patients. The current therapy was influenced by self-help in more than 50% of cases. CONCLUSION Physicians treating patients with brain tumours face a subgroup of well-educated people aiming to independently verify and possibly supplement and/or modify their prescribed care. With the steadily increasing use of internet resources, this approach can be expected to expand. Physicians should be prepared to deal appropriately with this subgroup of patients and their relatives to ensure that self-help activities support but do not endanger optimal care.