Yellow water after surgery for middle ear mastoiditis is often related to incomplete surgery, postoperative infection and other factors. 1. Incomplete surgery: If the condition of middle ear mastoiditis is more serious and the surgery is incomplete, the symptoms of yellow water may appear again within a short period of time after the surgery. 2. Post-operative infection: the surgery for middle ear mastoiditis is quite traumatic, if the surgery is not performed properly or if you don’t pay attention to the maintenance after the surgery, infection may occur, and the long-term inflammation stimulation will cause yellow water, accompanied by ear pain, tinnitus and other symptoms. Yellow water after mastoiditis surgery, it is necessary to go to the hospital to do relevant examinations to analyze the cause of the disease, including otoscopy, temporal bone CT, etc., to understand the cause of the disease and follow the doctor’s instructions to standardize the use of medication and treatment, so as to avoid delaying the condition.