We report a clinical and neuroradiological description of a severe case of Wernicke's encephalopathy in a surgical patient. After colonic surgery for neoplasm, he was treated for a long time with high glucose concentration total parenteral nutrition. In the early post-operative period, the patient showed severe encephalopathy with ataxia, ophthalmoplegia and consciousness disorders. We used magnetic resonance imaging (MRI) to confirm the clinical suspicion of Wernicke's encephalopathy. The radiological feature showed hyperintense lesions which were symmetrically distributed along the bulbo-pontine tegmentum, the tectum of the mid-brain, the periacqueductal grey substance, the hypothalamus and the medial periventricular parts of the thalamus. This progressed to typical Wernicke-Korsakoff syndrome with ataxia and memory and cognitive defects. Thiamine deficiency is a re-emerging problem in non-alcoholic patients and it may develop in surgical patients with risk factors such as malnutrition, prolonged vomiting and long-term high glucose concentration parenteral nutrition.