Wernicke encephalopathy is a rare but serious neurological pathology due to a vitamin B1 deficiency. It is commonly associated with heavy alcohol consumption. Other clinical associations are with hyperemesis gravidarum, starvation, and prolonged intravenous feeding. Most patients present with the triad of ophthalmoplegia, ataxia, and confusion. It can be associated with life-threatening complication like central pontine myelinolysis. When Wernicke encephalopathy is suspected, treatment with high-dose parenteral thiamine (vitamin B1) should be given. If it is not treated promptly or if treatment is inadequate it can lead to death or to the chronic memory disorder, Korsakoff syndrome. Recent studies have suggested that an association exists between Wernicke encephalopathy and genetic polymorphisms in the thiamine transporter (SLC19A2).