Wernicke encephalopathy is caused by thiamine deficiency in the central nervous 
system, and is defined by the triad of confusional symptoms, ocular alterations 
and ataxia. Some other factors may also predispose alcoholic patients to this 
deficiency. We report two patients with hyperglicaemia and ketoacidosis due to 
diabetes mellitus decompensation and chronic alcoholism who developed Wernicke 
encephalopathy before their hospital admission. The outcome was successful after 
intravenous thiamine administration and insulinotherapy. The presence of 
Wernicke encephalopathy in alcoholics with diabetic ketoacidosis, suggests that 
metabolic decompensation is essential in the onset of the disease.