From the page: "Many people experience a ringing or hissing sound in their ears or head in the absence of any external sound; this condition is called tinnitus or ringing ears. It is an annoying and frustrating symptom of some other underlying disease. Some of the common causes include damage to the nerve endings, ear infections, presence of ear wax or any foreign particle, senility, continuous exposure to loud noise, abnormal serotonin levels and as a side effect of certain medications and drugs."