The effects of chronic alcohol consumption (CAC) on the relative number of dentate gyrus granule cells and their dendritic trees, were studied in animals fed alcohol for 6, 12 and 18 months and in their respective controls. The granule cell density was estimated with the unbiased disector method. Following 6 months of alcohol consumption, the thickness of the dentate gyrus granular layer and the relative number of dentate granule cells were significantly decreased when compared with controls. The granule cell dendritic arborizations showed an increase of their dendritic extent in alcohol-treated rats. No significant differences were found in the density of dendritic spines between alcohol-fed and control animals. These results indicate the existence of hippocampal granule cell dendritic regrowth in alcohol-fed rats, probably occurring as a compensatory response to the granule cell deficit which follows the alcohol-induced granule cell degeneration. These degenerative and regenerative changes might have functional implications for the organization of the synaptic hippocampal circuitry after long periods of alcohol consumption.