The circulatory effects of stellate ganglion block (SGB) on the blood flow through the common carotid artery were determined in 35 patients in acute phase of idiopathic facial palsy (Bell's palsy). SGB was performed by para-tracheal approach with 8 ml of 1% mepivacaine. The blood flow was measured with an ultrasonic blood flowmeter before and 30 minutes after SGB at both sides of the common carotid artery in 20 cases. Measurement was performed continuously for 90 minutes on the palsy side in the other 15 patients. Before SGB, there were no significant differences between the blood flow of the palsy side and the intact side. Thirty minutes after SGB, the blood flow markedly increased to 169.4 +/- 6.2% on the performed side with no change on the non-performed side in 20 cases. In the other 15 patients, the blood flow increased significantly 5 minutes after SGB and reached its peak of 179.7 +/- 11.1% at 20 minutes later. This increase continued for 75 minutes after SGB. It is well known that impaired microcirculation in the facial nerve has an important role in the pathophysiology of Bell's palsy. In view of the fact that the nutrient arteries for the facial nerve are the peripheral branches of the external carotid artery, we believe that SGB which causes significant increase in the blood flow through the common carotid artery is an effective treatment in Bell's palsy.