dan - Fri, 04/09/2010 - 18:58
Rhubarb or "pie plant" is prized for use in pies, tarts, and sauces. Only the petioles are eaten, although herbal remedies use the leaves and roots. The high levels of oxalic acid and other compounds within the leaves are toxic to humans. The petioles contain lower levels of oxalic acid and, primarily, malic acid.