BACKGROUND: The large hemodynamic response induced by laryngoscopy and endotracheal intubation may cause serious cerebral complications. This study was performed to evaluate the effects of intralaryngotracheal 10% lidocaine spray on hemodynamic responses to endotracheal intubation for patients with a cerebral aneurysm. METHODS: Sixty patients with a cerebral aneurysm were randomly divided into three groups by lidocaine administration methods before endotracheal intubation: Group 1 (Control, 2% lidocaine 1.5 mg/kg, intravenous injection); Group 2 (10% lidocaine 1 mg/kg, intralaryngotracheal spray); Group 3 (10% lidocaine 1.5 mg/kg, intralaryngotracheal spray). Anesthesia was induced intravenously with midazolam (0.02 mg/kg) and thiopental sodium (2 - 3 mg/kg), and then maintained with 50% nitrous oxide in oxygen and 1.0 vol% isoflurane. Blood pressure and heart rate were measured preinduction, before laryngoscopy, immediately after epiglottis elevation, immediately after intubation and 3 minutes after intubation. Data were compared and analyzed within and between groups. RESULTS: Immediately after intubation, the increase in blood pressure and heart rate were blunted significantly in the groups 2 and 3 compared to the intravenous lidocaine injection group (P < 0.01). However, there were no significant hemodynamic changes between groups 2 and 3. CONCLUSIONS: The elevation of blood pressure and heart rate after endotracheal intubation can be prevented by intralaryngotracheal spray of 1 mg/kg of 10% lidocaine 3 minutes before endotracheal intubation.