Background: Stellate ganglion block has been proposed as one of the effective therapetic modalities for herpes zoster. However, the effect on the reduction of acute herpes zoster pain and postherpetic neuralgia is not well known. Objective: To evaluate the reduction of acute herpes zoster pain and the prevention of postherpetic neuralgia by stellate ganglion block. Methods: Twenty one patients with herpes zoster were included in this study, and were divided into two groups: the group treated with I.V acyclovir, analgesics and stellate ganglion block during 7-days of a hospitalization period, and a control group which were treated with I.V acyclovir and analgesics alone. To evaluate it`s effect on pain, the score of pain presented by patients, where initial pain was defined as 100 and no pain defined as 0, was recorded and compared between the groups. Results: An average day required for the relief of pain was significantly shorter in the treated group than the control group: the average number of days needed to reduce the pain score from 100 to 50, implicating relief of acute pain, was 2.3 days, compared to 3.7 days in the control group (p=0.036). The total duration of pain, implicating postherpetic neuralgia, was also significantly shorter in the treated group (17.4 days) than the control group (42.3 days) (p=0.035). Conclusion: Stellate ganglion block is an effective method which can be used to relieve acute herpes zoster pain involving the trigerminal and cervical nerves, and can prevent postherpetic neuralgia. (Korean J Dermatol 2006;44(6):681~687)