Thickening of the mucous membrane of the left maxillary sinus is likely to be left-sided maxillary sinusitis, which can occur at any age, with a higher incidence in adolescents, mostly as a result of a prolonged cold that does not heal. Patients may present with headache, nausea, vomiting, and also with nasal congestion, runny nose, and also with olfactory disturbance. The main treatment is the application of antibacterial drugs in the acute stage. Commonly used drugs include cephalosporin antibiotics, mainly ceftriaxone sodium, cefoperazone sulbactam, and also tinidazole, metronidazole or ornidazole for treatment. If the patient does not heal for a long time, it may cause chronic maxillary sinusitis, the patient may also have memory loss, inattention and thinking disorders, if necessary, you can improve brain metabolism treatment, commonly used drugs are Olacitant, Piracetam and Cytophosphorylcholine, also can be puncture flush treatment, so the patient must be treated promptly after the cold.