-A case is presented where a 25-year-old man developed a serious hypokalaemia (K + 2.2 mmol/l) during alcohol withdrawal, despite intravenous saline treatment and normal feeding. As hypokalaemia can be symptom-free, we want to draw attention to the combination of vomiting, malnutrition and alcohol withdrawal, as these can cause lethal complications. We therefore recommend that potassium serum level should be routinely monitored during alcohol withdrawal, even when this is being managed in the community.