Published reports of cure, morbidity, and mortality associated with the embolization of 1246 brain arteriovenous malformations during the last 35 years were reviewed. Embolization resulted in cure in 5% of arteriovenous malformations. The cure rates of embolization were 4% in reports of 708 patients published before 1990 and 5% in reports of 538 patients published since 1990 (P = not significant). Temporary morbidity from embolization was 10%, and permanent morbidity was 8%. Permanent morbidity was 9% before 1990 and 8% since 1990 (P = not significant). Death after embolization of brain arteriovenous malformations occurred in 1% of patients. Mortality associated with the embolization was 2% before 1990 and 1% since 1990 (P = not significant). Long-term morbidity associated with the use of neurotoxic embolization materials is worrisome but has never been proven.