The Authors examine a group of alcoholics, recording for each patients somatosensory, auditory and visual potentials, in order to check the presence in different systems of nervous fibers of subclinic alterations; they separate a group of patients with clinic polyneuropathie and a group without polyneuropathie. Subclinic alterations are confirmed in different measure in the two groups. Vit. B12 and pholic acid are also dosed in the serum.