In the course of a three-month administration of 15% ethyl alcohol solution as the only liquor offered to the experimental rats, SCO characteristics were analysed by methods of light microscopy, and SCO height measurements and by measuring the volume of the ependymocyte nuclei. There was abundant vacuolization of individual ependymocytes, as well as in groups of them, and increased apical and subapical neurosecretory accumulations. The volume of the nucleus was significantly augmented, whereas the SCO height remained within the limits of the control values. The changes obtained corroborate the idea of an active engagement of the SCO in the course of chronic alcohol consumption by experimental rats.