Edema of both feet may be caused by kidney disease, heart disease, liver disease, malnutrition and other reasons. 1. Kidney disease: for example, various primary glomerulonephritis, secondary nephropathy, etc., is the most common cause of edema, mainly due to a large amount of protein excreted in the urine, resulting in severe hypoproteinemia. 2. Heart disease: especially the right heart failure caused by the body circulation stagnation can lead to edema of the feet. 3. Severe malnutrition: causing hypoproteinemia, causing a decrease in vascular colloid osmotic pressure, leading to tissue interstitial edema, which can cause edema of the feet. In addition to the above reasons, liver disease, prolonged standing or venous return obstruction can also lead to bilateral lower extremity edema. Patients with double lower extremity edema, especially those whose edema does not disappear after lying down and resting, need to go to the hospital to improve the urine routine, liver and kidney function, cardiac function and other related examinations, so as to clarify the cause of the disease and then treat the cause.