Numbness of the big toe may be caused by blood sugar problems, lumbar spine problems, vascular factors and so on. 1. Blood sugar problem: Diabetes mellitus due to uncontrolled blood sugar, peripheral nerves are affected when the nerve ischemia, hypoxia, etc. leading to nerve numbness, such as the end of the hand, the end of the foot, the end of the big toe numbness and other symptoms. 2. Lumbar spine problem: due to the degenerative changes of the lumbar spine and external injuries caused by intervertebral disc fibrous ring rupture, the nucleus pulposus in the middle of the intervertebral disc protrudes from the ruptured annulus fibrosus, and compresses the back of the spinal cord and nerve roots. The main manifestations are lumbar pain, radiating pain and numbness in the lower limbs. Compression of the spinal cord nerve roots, there will be symptoms of big toe numbness, such as lumbar disc herniation, lumbar spinal stenosis, lumbar spine has slipped, will cause big toe numbness. 3. Vascular factors: there may be ischemia caused by lower extremity vascular sclerosis, stenosis, plaque, etc., resulting in poor blood supply, which will also show symptoms of numbness of the big toe. If there are symptoms of numbness in the big toe, it is recommended to go to the hospital as soon as possible for a comprehensive examination, to clarify the cause of the disease, and to carry out treatment under the guidance of the doctor.