The symptoms of swelling and pain on the left side of the foot: 1. It may be caused by low venous valve function in the lower extremities, reduced estrogen levels, and hypothyroidism. 2. It may be caused by cardiac factors. Patients with right heart failure have swelling in the lower extremities due to decreased right heart function and increased resistance of the inferior vena cava to return to the heart. At the same time, it may also be accompanied by symptoms of chest tightness, shortness of breath and weakness. 3, kidney diseases, such as nephrotic syndrome, reduced kidney function, when the patient’s body can not properly excrete metabolic toxins and water, the body’s albumin will be reduced, resulting in lower plasma colloid osmotic pressure thus causing lower limb edema symptoms. Therefore, when the symptoms of swelling and pain in the left foot surface appear, patients should rest in bed, avoid strenuous activities, and give physical therapy or topical anti-inflammatory and analgesic drugs to relieve the symptoms. If there is no relief within a short period of time, it is necessary to go to a regular hospital in time to improve the relevant auxiliary examination and choose a reasonable treatment method after clarifying the cause.