A double-blind, parallel group, multi-center study comparing efficacy and safety of oral 882C87 with oral Acyclovir for the treatment of acute localized herpes zoster in immunocompromised patients. Eligible patients will be randomly assigned to receive oral 882C87 200mg twice daily or oral Acyclovir 800mg 5X daily for 14 days. Patients will be evaluated daily X ten days, then twice weekly until day 28, then weekly for the next five months for rash, pain and complications, if any.