OXALIC ACID
IT is the chemical compound formula H2C2O4. This dicarboxylic
acid is better described with the formula HO2CCO2H. It is a
relatively strong organic a cid, being about 10,000 times stronger
than acetic acid. The dianion, known as oxalate, is also a reducing
agent and a ligand in coordination chemistry. Oxalic acid and
oxalates are abundantly present in many plants, most notably in
sour grass, and sorrel (including Oxalis), roots and leaves of
rhubarb and buckwheat.
At high concentrations, it is a dangerous poison, but such
immediately toxic levels are not found in foodstuffs but rather in
manufactures, such as some bleaches, some anti-rust products,
and some metal cleaners (among other things). It is also a
naturally occurring component of plants, and is found in
relatively high levels in dark-green leafy foods
In the human body, ingested oxalic acid is not a useful nutrient;
so, like all such unneeded components of diet, it is processed by
the body to a convenient form and that byproduct is then excreted--
in this case, in the urine. In the course of being processed by the
body, oxalic acid combines with other substances to form various
salts, called oxalates; usually, those salts are in solution, but
in high concentration some may precipitate out in crystalline form.
Such tiny crystals can cause damage to human tissue, especially
to the stomach, the kidneys, and the bladder. It is commonly
believed that oxalates contribute to the formation of kidney and
bladder stones; one common nutrient with which oxalic acid
combines is calcium, making the salt calcium oxalate, and
calcium oxalate is found in kidney stone
