why does pineapple hurt my mouth

Pineapple hurts the mouth because it contains an enzyme called bromelain, which breaks down proteins. Bromelain breaks down the proteins in the skin of your mouth—tongue, cheeks, and lips—causing a burning or tingling sensation. This protein breakdown causes irritation and mild inflammation in the affected areas. Additionally, pineapple's natural acidity can enhance this sensation by irritating the mucosal lining of the mouth further. This reaction is temporary, and your mouth heals quickly as the proteins regenerate and the enzyme is neutralized by saliva and stomach acid. Cooking or heating pineapple deactivates bromelain, so processed pineapple usually does not cause this irritation.