Introduction "Wernicke's encephalopathy" is the term applied to a disease process characterized pathologically by symmetrical lesions in the mammillary bodies, the walls of the third ventricle, the periaqueductal areas, and the floor of the fourth ventricle. Clinically, the disease is said to be characterized by disturbances of consciousness, paralysis of the external ocular muscles, ataxia, and sometimes polyneuritis.1,2 The disease results from a thiamine deficiency due to inadequate intake, faulty absorption due to gas trointestinal disturbances, or to unusually increased requirements such as in fever.3-8 Lesions resembling Wernicke's encephalopathy have been observed as a familial disease in infants in the absence of the above-mentioned circumstances, probably because of a defect in the metabolic pathways in which thiamine is usually involved.9 Due to the modern diet, often supplemented with vitamins, the avitaminoses have become relatively rare. Individuals addicted to alcohol, however, form a group in which the lack