Oral ulcers are manifestations of other diseases in the oral cavity and are not a singular oral disease. However, oral ulcers are primarily investigated in the department of stomatology, specifically within the oral mucosa department. Common causes of oral ulcers include a weakened immune system, which requires strengthening resistance through methods such as enhanced physical exercise or consuming more vegetables and fruits to increase vitamin intake. Oral ulcers may also be caused by irritation from dental calculus or tooth roots, categorizing them as traumatic ulcers, which necessitate the timely removal of irritating factors. Additionally, oral ulcers may be related to genetic factors or result from viral infections. Therefore, it is important first to identify the underlying cause for further investigation.