The skin of the pineapple plant is not considered poisonous, and while the entire fruit is considered non-toxic, the unripe flesh, thorns and leaves can have toxic effects. This is due to the enzyme bromelain, which is used as a meat tenderizer and is considered very low in toxicity. In large amounts, though, bromelain is believed to be the causal agent of symptoms of swelling or tenderness in and around the mouth. The leaves and thorns also contain sap that may be irritating to the skin.
Side Effects
Ingestion of the sap in pineapple leaves can lead to severe pain in the mouth, as well as skin irritation of the lips, tongue and mouth. If the sap gets on your skin, you may experience minor irritation or dermatitis, although this usually only lasts a few minutes. Ingestion of unripe pineapples causes throat irritation and may lead to diarrhea, vomiting and excessive menstrual bleeding. Eating large amounts of the pineapple core has also been associated with the formation of fiber balls, which are also referred to as bezoars, in the digestive tract.