Oral ulcers refer to localized lesions occurring on the oral mucous membranes, such as the inner cheeks, the underside of the tongue, and the mucous membrane of the tongue. There are various causes of oral ulcers. Commonly seen causes in clinical practice include repeated dental calculus, irritation from dental caries, prolonged intake of spicy foods, gastrointestinal dysfunction, acid reflux irritation, and endocrine disorders. Nutritional deficiencies due to selective eating can also lead to such mucosal lesions. Upon examination, scattered, isolated, crater-like ulcers can be found in any part of the oral cavity. The pain is significant in the affected areas, and bloody secretions may be observed when pressed. For treatment, patients are initially advised to use watermelon frost spray for external application, which has been found to be effective. Additionally, maintaining a bland diet, abstaining from smoking and alcohol, avoiding spicy foods, and controlling acid reflux with regular meals can gradually lead to improvement. (Note: The use of medications should be carried out under the guidance of a professional doctor.)