Rhubarb leaf blades are poisonous and must never be eaten
Rhubarb leaf blades are poisonous and must never be eaten. Only the leafstalks (the petioles) are edible. Harvest the stalks and cut the leaves off.
Well established A person has checked it against its sources. This one is about eating safely, not how the plant grows. The planner suggests it.
How it works
The leaf blades hold a toxic concentration of oxalic acid (and, per NDSU, anthraquinone glycosides), which the edible petioles carry only in trace amounts. Oxalic acid binds calcium and can damage kidney function; eating the blades causes cramping, nausea and, in quantity, can be fatal. The stalks are safe because the toxins concentrate in the leaf.
What to do about it
Cut the leaf blades off and discard them; eat only the stalks. Never cook or eat the leaves.
How much it matters: Not quantified as a threshold dose. The sources give the hazard and the compound, and NDSU's plant-toolbox entry rates the severity "Medium" and notes it is "TOXIC ONLY IF LARGE QUANTITIES EATEN", a qualitative caution with no stated gram figure, so none is given here.
The evidence
Evidence: checked against 5 sources in the research-based literature.
The 5 sources
The leaves, however, contain a toxic amount of oxalic acid and are poisonous. The ensuing cramps, nausea and sometimes death from ingestion suppressed interest in the plant for about two hundred years.
The leaves contain oxalic acid which can damage kidney function
Do not consume leaf blades, they contain large amounts of oxalic acid which can limit the body's ability to take up calcium.
Anthraquinone glycosides and soluble oxalates
Plants it applies to · 1
Read next
- Growing rhubarb for its stalks, since the leaves are poisonousRhubarb is one of the easiest perennials to plant, and the only common vegetable where part of the harvest is toxic. Which part, why, and the myths worth ignoring.
- When to pick your harvest, and how to make it keepThe picking signs for each crop, which ones must cure before they'll keep, the three kinds of pantry, and what should never see the refrigerator.
How this rule has changed
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Milpa Gardens. “Rhubarb leaf blades are poisonous and must never be eaten. Only the leafstalks (the petioles) are edible. Harvest the stalks and cut the leaves off.” Evidence grade: Well established. https://milpa.garden/rules/rhubarb-leaf-blades-poisonous-never-be-eaten/
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