What type of "fire" does oral ulcer belong to?

Canker sores may indicate various types of "excess heat" syndromes in traditional Chinese medicine, specifically including the following: 1. **Liver Fire**: Related to emotional excitement and emotional disharmony. Patients may also experience facial flushing, red and bloodshot eyes, bitter taste in the mouth, and unstable sleep. 2. **Stomach Fire**: Divided into excess heat and deficient heat. Patients with excess heat often exhibit symptoms such as canker sores, hard stools, dry mouth, and bitter taste. Those with deficient heat may experience mild cough with phlegm, red tongue, little coating on the tongue, and reduced appetite. 3. **Heart Fire**: Also divided into excess heat and deficient heat. Patients with excess heat commonly suffer from recurrent canker sores, swollen and painful gums, dark and scanty urine, irritability, and anger. Those with deficient heat may exhibit night sweats, irritability, dry mouth, and low-grade fever. Therefore, when canker sores occur, it is recommended to seek timely medical consultation to identify the underlying cause and receive treatment under a physician's guidance. Additionally, maintaining healthy eating habits, regular作息 (作息 should be translated as "lifestyle routine" or "daily schedule"), and a balanced mental state can also help prevent and alleviate canker sores.