The dizziness that occurs after a bump on the left side of the head may be caused by a mild concussion or a contusion. 1. Mild concussion: A mild concussion caused by a bump on the left side of the head is a relatively mild functional cranial brain injury, which often results in headache, dizziness, lightheadedness, nausea, and vomiting in some patients, and is usually relieved by rest. 2. Cerebral contusion: due to the left side of the head hit the brain tissue and dura mater collision or friction caused by organic damage, resulting in cerebral contusion, headache, dizziness, nausea and vomiting, etc., can be mannitol, glyceryl fructose, furosemide and other medications for treatment, such as the emergence of severe hemorrhage, the need for surgical intervention if necessary. Vertigo after the head suffered a collision induction accompanied by family members to the hospital, under the guidance of the doctor standardized treatment.