Are Rhubarb Leaves Poisonous?
South Dakota State University Extension says rhubarb leaves contain a toxic amount of oxalic acid, which is poisonous and can cause nausea, vomiting and, in severe cases, death. Oregon State University Extension says the leaves are toxic to humans and animals because of their high concentration of oxalic acid and soluble salts, and Purdue Extension says the leaf blades are not edible, either raw or cooked.
North Dakota State University Extension says the oxalic acid in the leaves can damage kidney function, that other compounds such as anthraquinone glycosides may also contribute to their toxicity, and that when rhubarb leaves were eaten as a vegetable substitute during World War I, the scientific literature documented poisonings and even deaths. It says the stems, or petioles, which resemble celery stalks, are the edible part because they contain only trace amounts of toxic compounds.
An NDSU Extension column says consuming large amounts of oxalic acid could affect the heart, digestive system and respiratory system, and that according to some sources a person would need to eat 11 pounds of rhubarb leaves to reach a fatal dose. A 2012 case report in BMC Nephrology describes acute kidney failure from oxalate crystals linked to excessive rhubarb ingestion, not specifically the leaves, in a patient with type 1 diabetes and previously normal kidney function.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Medical referenceSouth Dakota State University Extension says rhubarb leaves contain a toxic amount of oxalic acid that can cause nausea, vomiting and, in severe cases, death. South Dakota State University Extension ↗
- Medical referenceOregon State University Extension says rhubarb leaves are toxic to humans and animals because of their high concentration of oxalic acid and soluble salts. Oregon State University Extension Service ↗
- Medical referenceNorth Dakota State University Extension says rhubarb leaf oxalic acid can damage kidney function, and World War I leaf eating led to documented poisonings and deaths. North Dakota State University Extension ↗
- Medical referenceNDSU Extension says anthraquinone glycosides may add to rhubarb leaf toxicity, while the stems are edible because they hold only trace toxic compounds. North Dakota State University Extension ↗
- Medical referenceAn NDSU Extension column says large amounts of oxalic acid could affect the heart, digestion and breathing, and some sources put a fatal dose at 11 pounds of rhubarb leaves. North Dakota State University Extension ↗
- Medical referencePurdue Extension says rhubarb leaf blades contain oxalic acid and are not edible, either raw or cooked. Purdue University Extension ↗
- StudyA 2012 BMC Nephrology case report describes acute kidney failure with oxalate crystal deposits linked to excessive rhubarb ingestion in a patient with previously normal kidney function. Albersmeyer et al., BMC Nephrology, via PubMed Central ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.