A comparative study of seven techniques preventing pressor reactions to tracheal intubation (profound barbiturate anesthesia, conventional clinical doses of fentanyl, intravenous lidocaine, pentamine, glycerol trinitrate, sodium nitroprusside and magnesium sulfate) has been conducted in 75 patients with arterial aneurysms and arteriovenous malformations in brain vessels. The best preventive effect was observed with the use of glycerol trinitrate and conventional clinical doses of fentanyl. However, none of the above techniques could completely prevent pressor reactions to intubation.