Severe hypokalemia may constitute a life-threatening medical emergency. In the group of purging eating disorder patients, potassium blood levels tend to be chronically low while physical signs and symptoms may be absent. Nevertheless, these patients are frequently subjected to vigorous supportive treatment and often an aggressive diagnostic workup. We present a chronic purging anorexia nervosa patient in whom potassium blood levels reach a low of 1.6 mmol/L in the absence of physical symptoms. Purging eating disorder patients adapt to chronic hypokalemia. We believe the clinical/medical approach to this electrolyte disturbance in chronic eating disorder patients should be different from the approach to patients suffering from acute hypokalemia.