Levels of endorphins were determined in CSF from alcoholics while intoxicated or after 1 day, 1 week, and 3 weeks of abstinence, respectively, and from healthy volunteers. The level of endorphins was determined by a radioreceptor assay and two fractions were analyzed. With fraction 1, there were no significant differences between the groups, but the level was negatively correlated with the blood-alcohol level. The mean level of endorphin fraction 2 during the early withdrawal phase was significantly lower than those of the other groups. With respect to clinical conditions and monoamine metabolites, fraction 2 in early withdrawal correlated significantly to duration of abuse and age. During late withdrawal, fraction 1 level correlated to depressive symptoms and, after 3 weeks of abstinence, fraction 2 correlated to MOPEG levels. This study suggests that endorphin systems are affected during alcohol intoxication and withdrawal in alcoholics.