The numbness of the left lateral foot is considered to be caused by nerve compression or peripheral neuritis, as well as local blood circulation disorders. 1. Nerve compression: when the lumbar intervertebral disc herniation or pear-shaped muscle syndrome, may lead to sciatic nerve compression, peroneal nerve injury can also cause the symptoms of numbness of the outside of the left foot. 2. Peripheral neuritis: when there is chronic alcoholism or vitamin deficiency, viral infections may lead to inflammation of peripheral nerves, resulting in numbness of the outside of the left foot, accompanied by symptoms of limited mobility. 3. Blood circulation disorders: prolonged wearing of tight shoes or prolonged sitting, resulting in localized pressure and varicose veins, may lead to blood circulation disorders, which can cause numbness on the left side of the left foot. Numbness of the left lateral foot can be relieved by hot compresses or massage, but also to the hospital for examination, according to the specific causes of the disease, choose the appropriate treatment.