oxalates glycosides
Flower Color:
  • flower color
ornamental, fields, gardens

Time of Greatest Risk


Geographical Distribution

Rhubarb distribution - United States

Related Species


Rheum rhabarbarum

Pie Plant
4/ 10
Rhubarb (Rheum rhabarbarum) is a perennial plant with large fleshy rhizomes and large leaves with long, thick petioles. It is often grown for its stalks, which are a type of vegetable often found in supermarkets worldwide.

Toxic components
R. rhabarbarum can be toxic to horses if ingested.

The Chemistry of Rhubarb Infographic by
The Chemistry of Rhubarb Infographic by

The plant has high contents of oxalic acid as well as anthranoids, especially anthraquinone glycosides, aloeemodin, physcion, tannins (5-10%), pectin, phenolic, and carboxylic acids. The amount of oxalic acid in R. rhabarbarum varies considerably depending on the growth stage of the plant, season, and environmental conditions such as drought, cloudy days, or excessive rain. Oxalic acid combines with calcium in the blood to form insoluble calcium oxalate crystals that may be deposited into the kidneys which lead to renal stones and kidney damage.