To test the hypothesis that craving for alcohol in the alcohol-dependent individual is mediated by a limbic circuit involving the caudate nuclei, regional cerebral blood flow was measured with [99mTc]HMPAO SPECT during control and craving conditions in 9 alcohol-dependent subjects. In all subjects, blood flow in the head of the right caudate nucleus increased during the craving condition, and these blood flow increases were strongly correlated with the experimentally induced increases in craving for alcohol. These new findings suggest a functional role for the limbic striatum in the mediation of craving and impaired control over alcohol consumption.