Edema on the back of the feet is a relatively common phenomenon in the elderly, and is commonly caused by the following conditions: 1) heart failure; 2) kidney disease; 3) hypoproteinemia; 4) hypothyroidism; 5) side effects of medications. 1) heart failure, in which patients often have a history of underlying heart disease, such as coronary heart disease, hypertensive heart disease, or wind heart disease, the swelling on the back of the feet is most severe in the evening and will decrease the next morning. 2. Early kidney disease is common in the face and eyelids will appear edema, and then slowly spread to the back of the foot, if you look carefully at this time, there will be foam in the urine when urinating. 3. hypoproteinemia, is caused by malnutrition, such as some chronic liver disease, will cause malnutrition, low protein, low protein in the blood will cause edema, edema of the back of the foot. 4. hypothyroidism, hypothyroidism The most common is a kind of antihypertensive drug, such as nifedipine, amlodipine, levoclodipine, felodipine, which can cause edema of the back of the foot.