A brief review of the previous and generally inadequate methods for the treatment of Herpes Zoster is presented. The concept of "active premunization" by appropriate inducer to provide an objective treatment is defined. A "Premunization Inducer" (PIND) based on a particular non-infectious preparation of an avian pox ("avipox") virus has been shown to enhance non-specific defence mechanisms in the host by T-cell stimulation and to inhibit virus proliferation by the induction of Interferon. The mode of action, efficacy against different viruses and the safety of the preparation is described and discussed. 114 patients with Herpes Zoster were treated with this "premunization Inducer" either orally (for buccal absorption) or by means of a nasal spray. There were no side effects and in all cases there was a marked reduction in the duration of the illness up to the shedding of the last scab (about 15 days instead of the more usual 31 days). Pain was relieved in some cases within 6 hours and in the remainder within 2 days: a rapid resolution of the inflammation could be observed. There were practically no signs of postherpetic neurological complications among the patients treated (the usual incidence of post-herpetic neuritis is around 18%). The treatment of Herpes I and Herpes II infection other viral conditions will be reported elsewhere.