Aminobutyric acid (GABA) is implicated in the biochemical pathophysiology of alcohol intoxication, dependence and withdrawal. We therefore measured GABA in both cerebrospinal fluid (CSF) and plasma from 14 male alcohol-dependent patients during acute alcohol withdrawal (day 1) and again after 21 days of inpatient treatment (day 21). Plasma GABA levels on admission correlated with indices of liver function. When corrected for differences in liver function, plasma levels of GABA levels on day 1 were significantly higher than on day 21. CSF GABA concentrations were also significantly higher during withdrawal compared with concentrations after 3 weeks of abstinence. The change in plasma GABA levels correlated significantly with the change in CSF GABA levels, although there was no correlation between plasma and CSF levels at either time. These findings demonstrate that changes in CSF GABA may be reflected in plasma GABA, and they highlight the potential importance of the GABA system in alcohol dependence and withdrawal.