Interleukin-6 (IL-6) levels in the cerebrospinal fluid (CSF) and serum were measured in two immuno-competent children with herpes zoster meningitis, who had vesicles, fever, headache and vomiting before admission. The causative agent was identified as varicella zoster virus (VZV) by detecting an increased antibody index in the serum and specific DNA (by polymerase chain reaction) in the CSF. Both patients fully recovered after treatment with acyclovir. The CSF IL-6 levels were high (260.1 pg/ml, 106.1 pg/ml) at the acute stage and thereafter showed a rapid recovery. The serum IL-6 levels were normal. The increased IL-6 level in the CSF may reflect intrathecal inflammatory response following invasion of VZV into the central nervous system.