The swelling of the calf is divided into three main categories: first, the swelling can be significantly relieved after rest or sleep, and is considered to be caused by deep venous valve insufficiency, for which it is recommended to avoid prolonged sitting and standing, and to wear elastic stockings to prevent swelling. The second type of swelling is caused by heart problems, such as heart failure or low protein. It is recommended that cardiac ultrasound and biochemical tests be performed to clarify whether heart failure and low protein are present and to treat the original disease. The third type of swelling is caused by other causes, including thyroid disease, etc. In such cases, patients should undergo thyroid ultrasound and five tests of thyroid function to treat the original disease. In either case, patients must avoid prolonged sitting and standing, and pay attention to the observation of urine volume.