• Serial bilateral measurements of regional cerebral blood flow (rCBF) by the xenon Xe 133 inhalation method were made during 13 withdrawal periods in 12 male alcoholics with pronounced physical dependence. A significant global reduction of rCBF was found during the first two days of withdrawal. The largest decreases were seen in cases with a clouded sensorium and with an extended preceding drinking period. An rCBF distribution with relatively high temporal and low parietal flows during the first two days was coupled to aggravated symptoms. In two men who reported auditory and visual hallucinations during the measurements, elevated rCBF values were found in the temporal, Sylvian, and occipital regions.