The concentrations of the major norepinephrine metabolite, 3-methoxy-4-hydroxyphenylethylene glycol (MOPEG), in lumbar cerebrospinal fluid of alcoholic patients were markedly elevated during intoxication and successively declined during 1 and 3 weeks of abstinence. During intoxication the MOPEG concentration in cerebrospinal fluid showed a statistically significant correlation with the blood alcohol concentration. In healthy volunteers who received 80 grams of ethanol, the MOPEG concentration in cerebrospinal fluid increased significantly. Healthy subjects sampled during intoxication had significantly higher concentrations of MOPEG in the cerebrospinal fluid than did subjects sampled after the end of intoxication. The results indicate that alcohol administration markedly stimulates norepinephrine metabolism in the central nervous system in human subjects possibly by increasing unit impulse activity of central noradrenergic neurons.