The course of acute purulent meningitis and meningocephalitis was investigated in 101 patients using records and a questionnaire directed to all patients. Patients who survived meningoencephalitis were asked to come to a neurological examination. Neuropsychological status, EEG and Tc-HMPAO-Spect were also performed in these patients. The patients were treated with a combination of three antimicrobial agents which was commonly used at our hospital during the investigation time consisting of penicillin, a cephalosporine of the third generation and an aminoglycoside. 40% of the patients suffered from more or less severe neurologic sequelae; remaining cognitive deficits were also frequent. On the whole there was a tendency towards improvement in patients who suffered from less severe deficits at the time of discharge from hospital, patients with more severe deficits also showed slight improvement but generally did not reach a restitutio ad integrum. Regarding this, in our opinion a broad initial antimicrobial therapy should be used, although a statistically significant improvement of the patient's outcome by this could not be shown. Lethality as well as the frequency of complications do not seem to differ over many years although antimicrobial and intensive care treatment were improved. Thus, the outcome seems to depend largely on the occurrence of secondary focal complications or brain oedema.