A 55-years-old man with a history of alcoholism, hypertension and obesity was diagnosed of epidermoid carcinoma of the middle third portion of the esophagus. He was treated with two cycles of cytostatics with cisplatin and 5-fluorouracil. Due to his poor general health an inability to swallow solids and liquids, he received parenteral nutrition for 20 days using a commercial formula lacking in vitamins and minerals. During distal esophagectomy we observed a tendency to hypotension and severe metabolic acidosis that was unexplained by the hemodynamic profile and that persisted throughout the first 24 hours after surgery. Once these complications were corrected, he was weaned from mechanical ventilation and the following neurological signs were observed: temporal and spacial disorientation, aphasia, ophthalmoplegia with divergent strabismus and later conduction aphasia, amnesia and confabulation. Circulation was hyperdynamic, requiring inotropics and vasoconstrictors. Korsakoff syndrome secondary to Wernicke's encephalopathy was diagnosed, and the response to thiamine treatment was favorable. Beriberi can be found in hospitalized patients and the anesthesiologist may be involved in their perioperative care. Symptoms resolve easily with vitamin B1 treatment, which is ideally provided along with other hydrosoluble vitamins. Treatment should be prompt because delay leads to greater morbiomortality.