The main causes of bleeding tongue from eating pineapple are caused by allergic reactions and mucous membrane irritation. If necessary, people are advised to go to regular hospitals for treatment. 1. Allergic reaction: some people are allergic to pineapple, when eating pineapple, it will blister in the mouth, and when it breaks, the symptom of bleeding tongue will appear. It is recommended to go to the hospital to check the allergens and take treatment under the guidance of the doctor. 2. Mucosal irritation factors: Because the pulp of pineapple contains more acidic compounds, bromelain and other components, these components will stimulate the oral mucosa. After eating pineapple in excess, the symptom of tongue bleeding will occur. Daily eating pineapple, you can use water to wash a few times, or soak in salt water for a few minutes before eating, the symptoms are serious, should seek medical attention.