Cyanoacrylate is a satisfactory material for therapeutic embolization, but it has the disadvantage of not being radiopaque and polymerizing within 1 sec after contact with ionic materials. Its behavior was modified with varying concentrations of iophendylate and were able to satisfactorily control its polymerization from 1 to 30 sec. This control should allow penetration of arteriovenous malformations, which is necessary if cure is to result. The iophendylate adds radiopacity and seems to enhance the suspension of tentalum, another opacifying agent. Preliminary experience in dogs is encouraging, but too few humans have been treated with this method to recommend it as more than an experimental procedure at this time.