Background: Prevention of postherpetic neuralgia as well as management of the symptoms of the acute stage is an important therapeutic goal in the treatment of herpes zoster. Corticosteroid, acyclovir and sympathetic block have all been advocated as effective therapeutic tools for the treatment of the disease. Objective : This study was conducted to evaluate the necessity of sympathetic block for prevention of postherpetic neuralgia in acute herpes zoster. Methods : The author observed the duration and degree of pain and the incidence of postherpetic neuralgia in 54 patients with herpes zoster treated with three different therapeutic measures. Group A was treated with triamcinolone acetonide 80mg three times, acyclovir and sympathetic blockade, group B with triamcinolone acetonide 80mg three times and:""vclovir, and group C with triamcinolone acetonide 40mg three times and acyclovir. Results : 1. Addition of sympathetic blockade to corticosteroid and acyclovir therapy did not seem to reduce the duration of pain and incidence of postherpetic neuralgia. 2. The Incidence of postherpetic neuralgia was higher in the elderly, especially with underlying systemic disease including diabetes melitus, hypertension, etc. Al] the therapeutic measures could not completely prevent the development of postherpetic neuralgia in those patients. 3. Regarding corticosteroid dosage, daily triamcinolone acetonide 80mg for three consecutive days showed no better effect than daily 40mg for consecutive days. Conclusion : When herpes zoster was treated with proper dosages of corticosteroid and acyclovir in its acute stage, sympathetic block showed no additional beneficial effect. (Korean J Dermatol 1998;36(1): 1-6)