Wernicke encephalopathy is a synrome characterised by ataxia, ophthalmoplegia, confusion, and impairment of short-term memory. It is caused by lesions in the medial thalamic nuclei, mammillary bodies, periaqueductal and periventricular brainstem nuclei, and superior cerebellar vermis, often resulting from inadequate intake or absorption of thiamine (Vitamin B1), especially in conjunction with carbohydrate ingestion. Its most common correlate is prolonged alcohol consumption resulting in thiamine deficiency. Alcoholics are therefore particularly at risk, but it may also occur with thiamine deficiency states arising from other causes, particularly in patients with such gastric disorders as carcinoma, chronic gastritis, and repetitive vomiting.