The causes of lower limb edema are commonly the following: 1. From the perspective of yin and yang identification in Chinese medicine, lower limb edema is commonly caused by yin water, the so-called yin water as opposed to yang water, which first swells from the feet, ankles, and lower limbs and spreads severely to the whole body, often due to deficiency of spleen and kidney yang and malfunction of metabolism of qi and water; 2. common diseases in Western medicine, such as nephrotic edema, acute and chronic nephritis, nephrotic syndrome, and renal failure can See lower limb edema; 3, thyroid disease, especially after hypothyroidism, whole body edema occurs and lower limb edema appears; 4, cardiogenic edema, cardiogenic edema has a primary cause and starts from the lower part of the body first, so lower limb edema can also be seen in cardiogenic diseases; 5, malnutrition can also appear lower limb edema, which is due to low protein or vitamin B1 deficiency and edema; 6. Cirrhosis leads to edema, where patients first have fluid in the abdominal cavity, followed by edema in the lower extremities, which then spreads to the whole body to appear edema, and is also a common cause of lower extremity edema.