Wernicke's encephalopathy is an acute presentation of neurologic symptoms caused by thiamine (vitamin B1) deficiency. Wernicke's encephalopathy is often associated with chronic, heavy alcohol use. However, it can also occur in other contexts, including malabsorption, poor dietary intake, increased metabolic requirements, and in patients undergoing dialysis. This presentation reviews the epidemiology, pathophysiology, clinical manifestation, diagnosis, and management of this often-under-recognized condition.