Abstract

Oxalic acid, is present in different ionic forms in plants, in the form the acid, oxalate ion or salts, dependent on pH.
This has a profound effect on the potential toxicity of the oxalates. Acute oxalate toxicity most commonly causes renal pathology.
Insoluble oxalates, in the form of crystals (raphides) are used as an anti-herbivory protective mechanism by plants by causing physical damage to the lips, tongue and palate.
Endogenous synthesis of oxalate, linked to inherited enzyme and/or vitamin deficiencies may lead to renal pathology as well.