The most common medical problems in brain tumor patients involve the management of seizures, peritumoral edema, medication side effects, and venous thromboembolism. Despite the importance of these issues, there are very few studies specifically addressing them. Nonetheless, there has been some progress in recent years. There is increasing evidence that brain tumor patients who have not had a seizure do not benefit from prophylactic antiepileptic medications. Patients taking corticosteroids are at greater risk of Pneumocystis carinii pneumonia and may benefit from prophylactic therapy. There is also growing evidence suggesting that anticoagulation may be more effective than inferior vena cava filtration devices for treating venous thromboembolism in brain tumor patients and that the risk of hemorrhage with anticoagulation is relatively small.