Usually, afternoon calf swelling disappears in the morning may be a normal physiological phenomenon, there is no danger. But it may also be caused by diabetes, nephrotic syndrome and other diseases, if there is no active treatment, there will be some danger. 1. Physiological phenomenon: swollen calves in the afternoon may be due to a morning of standing or sedentary, resulting in the lower extremities of the deep veins of the venous valves function is reduced, thus appearing venous return obstacles, the phenomenon of swollen calves, after a night’s rest, the swelling will disappear in the morning. This is a normal physiological phenomenon and is not dangerous. 2. Pathological phenomena (1) Diabetes mellitus: Diabetes mellitus can also cause swelling of the calves if the blood sugar level is not well controlled. This condition requires the use of hypoglycemic drugs, and severe diabetes can be dangerous, leading to diabetic ketoacidosis or causing other complications. (2) Nephrotic syndrome: If the swelling of calves is caused by nephrotic syndrome, it needs to be actively treated, the prognosis is better and the degree of danger is less, but it is usually difficult to achieve complete eradication. If the swelling of calves is not caused by physiological reasons, it is recommended that patients go to the hospital in time to avoid delaying the treatment and causing danger.