Oxalic acid is excreted in the urine as calcium oxalate. The daily quantity excreted amounts to about 20 milligrams. Oxalates form in the body from foods containing oxalic acid such as rhubarb, spinach, beet leaves, tomatoes, cranberries, gooseberries and pineapple.
Oxalates are also formed in the body when there is incomplete oxidation of carbohydrate food. When you eat fruit or vegetables rich in oxalates, you should also take food rich in calcium, such as milk and cheese, because the oxalates use up and carry away much calcium from the body.
There is a great increase in oxalates in the urine in cases of diabetes, gout, constipation, nervousness, chronic skin disease, excessive food intake , inactivity and sedentary occupation.
Oxalic acid is a household article used for cleaning purpose, and because it looks like epsom salt it is sometimes taken internally by mistake , and causes poisoning with symptoms of severe, burning pain in the throat, gullet and stomach, a sour taste in the mouth, and vomiting with blood.
In this event, give the victim powdered chalk in water, and lots of warm water to make him vomit more and wash away as much of the poison as possible.
Also give him a solution of baking soda in water, milk of magnesia and milk. A dose of any oil, after the stomach is cleared, will help relieve the burning pain.