What acid is found in rhubarb leaves?
Rhubarb toxic rhubarb leaves have been used in flavouring extracts, after the oxalic acid is removed by treatment with precipitated chalk (i.e., calcium carbonate). Oxalic acid can also be found in the stalks of rhubarb, but the levels are too low to cause any bodily harm. The (median lethal dose) for pure oxalic acid in rats is about 375 mg/kg body weight, or about 25 grams for a human. Other sources give a much higher oral LD (lowest published lethal dose) of 600 mg/kg. While the oxalic acid content of rhubarb leaves can vary, a typical value is about 0.5%, meaning
Rhubarb to mimic the popular strawberry rhubarb pie. Rhubarb root produces a rich brown dye similar to walnut husks. It is used in northern regions where walnut trees do not survive. For cooking, the stalks are often cut into small pieces and stewed (boiled in water) with added sugar, until soft. Little water is added, as rhubarb stalks already contain a great deal of water. Rhubarb should be processed and stored in containers which are unaffected by residual acid content, such as glass or stainless steel. Spices such as cinnamon, nutmeg, and ginger are sometimes added. Stewed rhubarb or rhubarb sauce,