All parts of Rhubarb are toxic with oxalic acid, however it is the green leaves that should not ever be eaten. The leaves make a wonderful organic insecticide that wipes out aphids as it suffocates them. Please see here.
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The poison in Rhubarb leaves is:
"Oxalates are contained in all parts of rhubarb plants, especially in the green leaves. There is some evidence that anthraquinone glycosides are also present and may be partly responsible. It is not clear as to the exact source of poisoning from rhubarb, possibly a result of both compounds. The stalks contain low levels of oxalates, so this does not cause problems."
However I Love rhubarb to eat normally, especially with a sprinkle of ginger and nutmeg. Nutmeg is known to reduce any oxalic acid in spinach and rhubarb.
Don't stop eating the stuff as it is wonderful and the leaves are used by some gardeners to put under potato's as they claim it stops potato blight. That has yet to be proved but they swear by it.
Kindest regards from across the Atlantic.
Neil.
