A severe shortage of potassium in body fluids may cause a potentially fatal condition known as hypokalemia.  Hypokalemia typically results from loss of potassium through  diarrhea, diuresis, or vomiting. Symptoms are related to alterations in  membrane potential and cellular metabolism.  Symptoms include muscle weakness and cramps, paralytic ileus, ECG abnormalities, intestinal paralysis, decreased reflex response and (in severe cases) respiratory paralysis, alkalosis and arrhythmia.
In rare cases, habitual consumption of large amounts of black licorice has resulted in hypokalemia. Licorice contains a compound (Glycyrrhizin) that increases urinary excretion of potassium.