Food poisoning of oxalic acid

Oxalic acid occurs in the cell sap of Oxalis and Rumex species of plants as the potassium and calcium salt.

It is the metabolic product of many molds. Oxalic acid is soluble in water, alcohol and glycerol; slightly soluble in ether; insoluble in benzene, chloroform, and petroleum ether.

Oxalic acid is a strong poison. It is nephrotoxic and has a corrosive action. The toxic symptoms from ingestion include vomiting, diarrhea and severe gastrointestinal disorder, renal damage, shock, convulsions and coma.

Consumption of large amounts of plants high in oxalic acid, or consumption of moderate amounts over vela weeks, can cause serve calcium deficiency.

Death may result from cardiovascular collapse. Oxalic acid may be absorbed into the body through skin contact. It is corrosive to the skin and eyes, producing burns.

There are many plant materials known to be toxic to man. These includes: rhubarb leaves, spinach water and solanine in green and sprouting potatoes which contain oxalic acid. Rhubarb is a common and when season, widely consumed plant in Europe and Asia.

In normal circumstances, there is no danger in eating moderate quantities of these foods as part of a well balanced diet. The lethal dose is approximately 10-25 g depending on age.
Food poisoning of oxalic acid