There are many reasons why the left hand is always numb, including non-disease factors and disease factors, which require an accurate judgment according to the specific situation and targeted treatment according to the cause. I. Non-disease factors: Patients sleep in the left side position for a long time, or usually like to use the left elbow to support the body, compressing the left hand or left arm blood vessels and nerves, which will lead to numbness in the hand; the left hand is cold for a long time, and poor blood circulation will also lead to numbness in the left hand. Patients need to improve the bad habits, strengthen the warmth, the left hand always numbness can be alleviated. Second, disease factors: 1, central neuropathy: If patients have cerebral ischemia, insufficient blood supply, cervical spondylosis, cervical disc herniation, etc., resulting in the right central nerve pressure, damage, etc., can not function, there will be left hand numbness, need to identify the cause, take medication or surgery, etc., to restore central nerve function; 2, peripheral lesions: such as diabetes patients with peripheral nerve often appear inflammation, the lesion in the nerve innervating the left hand, the left hand can appear numbness, dysfunction and other conditions, need to use drugs to correct blood sugar in a timely manner. In addition, nerve damage to the left hand, muscle trauma can also occur hand numbness; 3, atherosclerosis: atherosclerosis patients may have insufficient blood supply to the extremities, so that the local nervous system secondary to ischemia and hypoxia, thus triggering numbness in the extremities, but single is rare, can be targeted to expand blood vessels, blood revitalization treatment, serious cases need vascular stent intervention.