Eating pineapple will rot your mouth may be caused by allergy, or it may be caused by mouth ulcers and lipitis. Pineapple contains a protease enzyme, if the organism is allergic to the protease enzyme in pineapple, after eating it, there may be broken skin in the mouth, vesicles in the corners of the mouth, pain in the mouth, as well as itching of the skin, flushing, abdominal pain, diarrhea, vomiting, breathing difficulties, numbness of the mouth and tongue, excessive sweating, urticaria, anaphylaxis and other allergic reactions. Patients with mouth ulcers will be manifested as oral pain, the soft palate of the mouth or lip area of the round, oval ulcer surface depression, so the patient will eat pineapple after the symptoms of rotting mouth. Lipitis will have lip peeling, lip swelling, lip burning pain, oozing scabs and other manifestations, so patients with lipitis patients eating pineapple will also show rotten mouth. It is recommended that patients who eat pineapple after the appearance of rotten mouth need to consult a doctor in a timely manner, you can choose the appropriate measures under the guidance of the doctor to treat. In addition, if the patient is allergic to pineapple, avoid eating pineapple.