One plant you probably didn’t expect to be poisonous: Pineapple! But don’t worry it is only poisonous in certain circumstances. The ripe fruit is edible and is the familiar pineapple found in grocery stores. The leathery rind, leafy top, and tough core are removed and the sweet, juicy, tangy, acidic, yellow or white flesh is eaten. Besides being edible, the fruits also contain bromelain, which is used in meat tenderizers and for various medicinal purposes. What is poisonous is the green, unripe fruits and they can cause throat irritation and gastrointestinal upset if eaten. Sap from the leaves contains ethyl acrylate and calcium oxalate crystals and can cause minor skin irritation and severe mouth pain if ingested.