We present clinical and virological data on 9 patients, 7 women and 2 men aged 31-56 years, with recurrent aseptic meningitis (Mollaret's meningitis). Polymerase chain reaction detected Herpes simplex virus type 2 DNA in cerebrospinal fluid samples from all patients collected during their latest attacks of meningitis. Six patients had no history of genital herpes. Only 1 patient was offered prophylactic antiviral treatment during the study period (45 months).