A syndrome is described which affects subjects whose consumption of beer is considerable but who take no or little ordinary food. The symptoms include fatigue, dizziness, and muscular weakness; the biochemical changes are hyponatraemia and hypokalaemia. The disorder is rapidly resolved by stay in hospital. Beer is poor in Na (1-2 meq. per litre). Consequently these patients' intake of Na was low, and the production of urea was very low.