Patients with high blood glucose alone usually do not have swollen feet. If swollen feet occur, attention should be paid to the occurrence of diabetes complications or other diseases that cause swollen feet. The common complications of diabetes that can cause swollen feet are diabetic nephropathy, diabetic vascular disease, infection, heart disease caused by diabetes, and so on. 1. Diabetic nephropathy: Diabetic nephropathy can cause increased urinary protein, resulting in hypoproteinemia, which can lead to edema. 2. Diabetic vasculopathy: high blood sugar can damage the peripheral blood vessels, and when it damages the veins of the lower limbs, resulting in thrombosis or occlusion of the veins of the lower limbs, the obstruction of the venous blood return in the lower limbs can lead to edema. 3. Infection: Hyperglycemia is easy to be combined with various infections, when the patient has wounds or breaks in the lower limbs, microorganisms on the skin surface (including bacteria, fungi, etc.) are easy to invade into the human body and lead to infections, which are usually accompanied by redness, swelling, heat and pain. 4. Heart disease caused by diabetes: when the heart disease caused by diabetes is serious, heart failure can occur, and if it is right heart failure, then it can lead to blood stasis in the circulation, and edema of both lower limbs can occur. 5. Other diseases leading to edema include acute and chronic glomerulonephritis, right heart failure due to other causes, cirrhosis of the liver, lymphadenitis of the lower extremities, and lowered serum albumin due to various causes. Regardless of the cause of foot swelling should be taken seriously, and timely to the hospital.