Plants contain oxalates for a few reasons. The first is that plants do not have an excretory system like animals, so oxalates allow plants the ability to bind up excess calcium (Webb 1999).Plants high in oxalates can have negative effects on the ability of animals to absorb calcium after eating taro leaves as forage (Hang 2011). In humans, eating foods with a high amounts of oxalates can increase kidney stone formation (Juajun2012).The second reason oxalates are said to occur in plants is to prevent herbivory (Webb 1999). Oxalate crystal shapes (raphidesand styloids) are like small needles and can be found in plants such as Monsteradeliciosaand Colocasiaesculenta.Consumption of plants containing raphidesand styloids cause an unwanted reaction. The crystals within plant matter from monsteraare said to cause oral and skin irritation (Morton 1987). Plants containing high levels of oxalates are able to be consumed if processed correctly or harvested at the right time.