Bleeding in the mouth when eating pineapple is usually caused by lipitis or allergy to certain ingredients in pineapple, which can be dealt with by applying lip balm, eating a light diet or taking medication, depending on the specific situation. For lipitis triggered by eating pineapple mouth bleeding, you need to stop eating pineapple immediately, so as not to cause more intense irritation to the mouth. In daily life, you can apply lip balm to improve the symptoms of mouth dryness, and at the same time, during the recovery period, you also need to try to avoid spicy and stimulating foods, maintain a light diet to promote mouth recovery. If the allergic phenomenon is triggered by pineapple protease, resulting in bleeding mouth when eating pineapple, you need to go to the stomatology department of the regular hospital in a timely manner for diagnosis and treatment. It is recommended that after the allergens are identified, topical topical application of tretinoin acetate cream or antihistamines such as cetirizine hydrochloride tablets and loratadine capsules should be taken under the guidance of the doctor for treatment. Before eating pineapple, soak it in sugar water or lightly salted water to reduce the irritation of certain components of pineapple to the mouth. If discomfort occurs, stop eating pineapple and go to the hospital immediately for examination and treatment if necessary.