The causes of foot swelling may be: 1. renal insufficiency, due to abnormal protein metabolism, prone to edema in the low hanging parts of the body, especially after prolonged standing, foot and lower limb swelling will be more obvious. 2. abnormal circulatory function, mostly seen in patients with abnormal cardiopulmonary function, patients may be accompanied by active chest tightness, breath-holding and other symptoms. 3. varicose veins in the lower limbs, etc., due to impaired venous blood return in the lower limbs, resulting in foot and lower limb edema. 4. 4, foot arthritis, gout, etc., due to inflammatory stimulation, there will be edema situation, more uric acid, white blood cells and other examination items elevated performance. 5, some patients with lumbar disc herniation, will also have foot edema situation, serious may be accompanied by lower limb numbness, etc.