A survey of the cerebrospinal fluid (CSF) amino acids, glutamine, and glutamic and gamma-aminobutyric (GABA) acids was made in 168 children, aged 1 to 14 years, with various neurological infections. The glutamic acid and glutamine concentrations in the CSF of children with severe forms of acute serous and bacterial meningitis were about three to four times as great as in controls. The indices returned almost to normal during recovery. GABA is absent in normal CSF, but appeared in the CSF of patients with bacterial meningitis. Its determination may be used as an additional test to differentiate between serous and bacterial meningitis.