Weakness and numbness of the left leg may be related to improper posture, cerebrovascular disease, lumbar disease and other factors, which need to be treated with general therapy, medication or surgery. 1. For those caused by improper posture, pay attention to adjusting posture, avoiding pressure on the left leg, and perform leg massage under professional guidance. 2. For cerebrovascular diseases, such as cerebral infarction, oral aspirin and other antiplatelet drugs, warfarin and other anticoagulants can be prescribed; for large cerebral infarction, decompression of the bone flap is feasible. 3. For lumbar diseases, such as lumbar intervertebral disc herniation, oral ibuprofen and other non-steroidal anti-inflammatory drugs, methylcobalamin and other nutritive nerve drugs as prescribed by the doctor; for those who are ineffective in conservative treatments, decompression surgery can be considered. It is recommended that the left leg weakness and numbness to go to the hospital in time, to clarify the cause of the disease, under the guidance of the doctor for standardized treatment.