Swelling on one foot and normal on the other may be caused by local injuries, varicose veins in the lower limbs and gout. 1. Local injury: Swelling on the top of the foot is caused by traumatic stimulation, which is often accompanied by pain or ulceration. If the symptoms are mild, no treatment is needed, and the swelling will dissipate on its own after a few days of observation. If the symptoms are serious, you can take some anti-inflammatory drugs such as amoxicillin, levofloxacin, metronidazole, etc., and at the same time, you can use Yunnan Baiyao to reduce the symptoms. 2. Varicose veins of lower limbs: Due to blood stagnation and weak walls of veins, varicose veins of lower limbs are caused, and one foot will be swollen when standing and walking for a long time, and the other one will not be swollen. Patients can elevate the affected limbs and take medicines such as flavonoids, hepatic saponins, coumarins and so on as prescribed by the doctor for treatment. 3. Gout: gout will make the purine metabolism abnormal, uric acid rise, causing swelling of the lower limbs, appearing one foot swelling, the other foot is not swollen situation. Patients can follow the doctor’s instructions to take drugs such as indomethacin, diclofenac, etoricoxib and so on to relieve the symptoms. If one foot is swollen and the other is normal, the cause should be clarified in time, and if the symptoms continue to be unrelieved, it is necessary to go to the hospital for diagnosis and treatment, so as not to delay the condition.