Swelling and stiffness in the lower leg after sitting for a long time is usually due to deep vein thrombosis in the lower leg, or lymphangitis or blocked lymphatic vessels. It is best to go to the hospital for an ultrasound examination of the lower extremities to see if there is any thrombosis in the deep veins. If so, intervention, thrombolysis, or embolization is required, and a filter is placed in the inferior vena cava to avoid life-threatening pulmonary embolism due to dislodgment of the embolus. If there is significant lymphangitis, penicillin or amoxicillin sulbactam sodium or ampicillin sodium sulbactam sodium can be given intravenously for effective anti-inflammatory effects and to reduce the local inflammatory lesions of lymphangitis. In addition, the leg should be elevated above the level of the heart in a lying position to promote venous return and local inflammation metabolism and absorption through gravity, which can effectively relieve the swelling and stiffness of the lower leg. Standing and sitting should be reduced in general, otherwise the swelling will be aggravated.