Dry mouth can be caused by fire, which is categorized into two main types: real fire and imaginary fire. However, not all dry mouth is caused by fire, the specific causes need to be combined with the patient’s other symptoms to decide. Fire often involves more than one internal organ, there can be stomach fire, lung fire, and so on. Their clinical characteristics are different. Take stomach fire as an example. Solid fire: in addition to dry mouth, accompanied by burning pain in the stomach and epigastrium, aggravated by pressing, acid reflux, heartburn, easy to hunger, food that is vomiting, bitter mouth, like to drink cold water, short yellow urine, constipation and so on. Deficiency fire: In addition to dry mouth, accompanied by vague burning pain in the stomach and epigastrium, stomach distension, conscious hunger but do not want to eat, eating less, dry stools, short urine, etc.. If the dry mouth is not relieved for a long time or accompanied by other discomforts, it is recommended to consult a doctor in time.