We must be assured that sympathetic ganglion block interrupts a vicious cycle of nerve impulses. Therefore, it prevents vasospasm and improves local circulation. The sympathetic ganglion block is effective in acute stage of herpes zoster and reduces the incidence of post-herpetic neuralgia. Herpes zoster is more often involved in an immunosuppressive imbalance. Three cases of herpes zoster were treated by repeated sympathetic ganglion block with 1% proved. Duration from onset of pain was 1 week, 1 month and 2 months, respectively. The block decreased the degree of pain markedly and dried up the vesicle in the early stage. Two of these three cases had suffering from diabetes melitus.