Beriberi is a disease caused by thiamine (vitamin B1) deficiency. Peripheral and central nerve involvement causes psychosis and memory loss as well as cardiocirculatory effects. We report the case of a 35-year-old woman 8 weeks pregnant who came to the emergency department after bouts of nausea and vomiting over a period of 6 days, with intolerance of both solids and liquids. The initial diagnosis of gastroenteritis was later changed to hyperemesis gravidarum. Episodes of vomiting and nausea continued 48 hours after admission, accompanied by vertical nystagmus, ataxia, and diminished osteotendinous reflexes. Evaluation of the clinical picture confirmed vitamin B1 deficiency, leading to a diagnosis of Wernicke-Korsakoff syndrome. Symptoms improved with thiamine therapy but did not entirely disappear. The patient was admitted for elective cesarean section at 37 weeks' gestation. Examination revealed neurological involvement (horizontal and vertical nystagmus) and general anesthesia was therefore chosen to assure adequate hemodynamic control given the possibility of cardiocirculatory alteration.