The main application of mannitol injection and dexamethasone injection for intravenous infusion treatment after a lumbar disc herniation in order to eliminate swelling and dehydration is determined by the specific swelling caused by the lumbar disc herniation. When a lumbar disc is herniated it compresses and irritates the nerve roots, which triggers abnormal blood circulation to the nerve roots and can lead to swelling of the nerve roots. In addition, the lumbar intervertebral disc is composed of proteins, and the contact of the proteins of the lumbar intervertebral disc with the nerve root will also trigger sterile inflammation and form swelling, so to eliminate the swelling you need to use mannitol injection and dexamethasone injection. Dexamethasone injection suppresses the obvious swelling due to the inflammatory response, and mannitol injection causes the edema produced by the nerve roots to subside rapidly.