The main causes of potassium deficiency include insufficient intake of potassium, excessive potassium excretion by kidney, and long-term diarrhea. 1. Insufficient intake of potassium: If the patient usually has small meal size, poor eating, anorexia, partial feeding, etc., it will cause insufficient intake of potassium, resulting in potassium deficiency. 2. 2. Excessive renal potassium excretion: patients with renal diseases such as renal tubular acidosis; endocrine diseases such as primary aldosteronism; and application of potassium-excreting diuretics such as furosemide and hydrochlorothiazide may have potassium retention capacity. All of them may have decreased ability of the kidney to preserve potassium, and potassium is excreted too much from urine, resulting in potassium deficiency in human body. 3. Prolonged diarrhea: If you often eat cold and irritating food, you may suffer from indigestion, which may cause the process of diarrhea leading to a large amount of potassium loss from the digestive tract, resulting in the symptoms of potassium deficiency. There are many factors that cause potassium deficiency in human body, patients should seek medical treatment in time, after clarifying the cause of the disease, under the guidance of doctors for professional treatment, to avoid the adverse consequences of self-medication.