Swollen feet are a common symptom in middle-aged and elderly people, but some young people, of course, may also have swollen feet. We know that swollen feet do not appear for no reason, so what are the causes of swollen feet? It may be a problem that we are interested in and want to understand. Today we will learn more about it. The causes of swollen feet are mainly the following: a. Inferior vena cava foot swelling, mainly caused by poor inferior vena cava reflux, generally manifested as unilateral foot swelling. Second, the weather, when it is hot, most of the body’s peripheral blood vessels are in a state of expansion, so that capillary congestion, so that the skin, subcutaneous and soft tissues are showing mild swelling, the same reason as heat expansion and cold shrinkage. Third, improper diet, due to eating less, lack of quality protein, is also easy to appear swollen feet. Fourth, overweight, thus causing excess body fat will also prevent body fluids from the legs back, causing swollen feet. Fifth, kidney disease causes swollen feet. For example, nephritis can cause swollen feet, and certain swollen feet may be a harbinger of a disease. Sixth, idiopathic foot swelling: mostly seen in elderly women, more feet at the same time, the degree of light, often when standing for a long time or exertion, if lying down or after rest can gradually disappear. Seven, male elderly people who suffer from prostate enlargement or prostate inflammation, individual elderly people who suffer from bladder tumor and renal insufficiency due to urinary retention, eventually appear swelling of the lower limbs. Eight, internal organ diseases can cause swelling, like heart disease, cirrhosis of the liver, kidney disease patients. These factors are the most common causes of swollen feet, in fact, there are many unknown factors. Once the foot swelling is the need to pay attention to, it is best to go to the hospital to do physical examination, such as liver function, kidney function, electrocardiogram, blood pressure, blood sugar, blood lipids, etc., in order to further clarify the causes of swollen feet and do reasonable treatment.