Because pineapple contains glycosides and bromelain that have an irritating effect on the oral mucosa, mouth pain can occur after eating too much. Pineapple belongs to a kind of fruit, rich in nutrients, but contains glycosides and bromelain with stimulating effects, which will have an irritating effect on the oral mucous membrane tissues and the corners of the mouth, so there will be symptoms of mouth pain. When consuming it, you can cut the pulp into cubes and macerate it in dilute salt water to leach out the glycosides, which is conducive to reducing the stimulation of the oral cavity. Also pay attention to moderation, do not ingest too much pineapple at once. If the pain is obvious, you can gargle with light salt water. In severe cases, medication can be used for treatment under the guidance of a doctor. However, it should be noted that the medication must be used under the guidance of a doctor, and should not be used on its own.