The Working Party was instituted to investigate the rationale of therapeutic antibiotic usage in patients with brain abscess and to make recommendations for current practice. A systematic review of English language publications on brain abscess over the last 25 years was carried out using electronic databases and secondary sources, and data were evaluated. Few publications were identified where the microbiological procedures were adequately described and many authors continue to report sterile pus in a proportion of cases. The vast majority of reports were retrospective neurosurgical assessments in which details of laboratory procedures and antibiotic regimens were missing. There are no published reports of controlled clinical trials or comparative therapeutic studies. The recommendations made by the Working Party are based on relevant published information and the expertise of Working Party members. Recommendations vary according to the location of the abscess which reflects the likely source of the infection and therefore the bacterial types most likely to be present in aspirated pus. Bacteria with multiple resistance to antimicrobial agents do not feature significantly in cases of brain abscess.