Swelling of the right foot without swelling of the left foot may be due to trauma to the right foot or varicose veins or venous thrombosis of the right lower extremity. 1. Right foot trauma: Due to right foot trauma, blood enters the subcutaneous tissue from the wound and swelling occurs. If there is no damage to the skin, cold compresses can be applied within 72 hours, hot compresses can be applied after 72 hours, and the right limb can be elevated to promote swelling. 2. Varicose veins and deep vein thrombosis in the right lower limb: Varicose veins or deep vein thrombosis in the right lower limb can lead to blood return obstacle in the right foot and swelling of the right foot. There may be other reasons for the swelling of the right foot but not the left foot, so you should go to the regular hospital in time, and the doctor will judge the specific reasons according to the symptoms, signs and auxiliary examination, and give the correct treatment for the reasons.