Morsicatio buccarum et labiorum is a form of chronic oral mucosa disease caused by habitual cheek or lip biting. The affected mucosa shows a shredded appearance. The patients may feel their oral mucosa rough. In present, there have not been unified denomination and systematic introduction about this disease in our country. Two cases were reported here. The pathogenesis, clinical manifestation, pathology, diagnosis, differential diagnosis, treatment and prognosis about this disease were also discussed.