Chelation is the chemical binding of one substance to another and comes from the Greek word meaning "claw." Ethylene diamine tetra acetic acid (EDTA) is a synthetic amino acid which has the ability to attach itself to metals and minerals, forming a particular kind of bond called a chelate. Metals are bound more tightly than minerals and are removed from the body.

EDTA was developed in Europe in the first half of this century for use in industry and water purification. It was found to have particularly good chelation (binding) properties especially in regards to the heavy metals, and so it became an inexpensive way to purify drinking water. It was also used in WWII in Germany to treat arsenic gas exposure. In the 1940s, US naval physicians began noticing a high incidence of lead poisoning among sailors assigned the duty of painting warships. The physicians used to intravenous (IV) EDTA chelation therapy to remove the lead with excellent results. In the 1950s, physicians treating heavy metal toxicity also noticed that their patients with angina no longer complained of chest pain after a few EDTA treatments, and EDTA chelation therapy became popular in the 1960s as a treatment for coronary and other vascular disease. Since 1953, the U.S. Food and Drug Administration (FDA) has recognized EDTA as a treatment for lead poisoning.

With the advent of evidence based medicine, EDTA therapy lost favor and has been regarded as "alternative medicine" until just recently. Due to 40 years of positive data, the National Institutes of Health (NIH) is starting a double blind study of patients with coronary artery disease in March 2003. Estimates about the numbers of physicians practicing chelation therapy are difficult to obtain because many physicians have been reluctant to make themselves objects of scrutiny.

Scientists, as well as the FDA, generally agree that controlled scientific tests are necessary to conclusively establish whether a medical treatment is effective, and in particular, whether EDTA is effective in treating vascular diseases. Observations by individual doctors and other kinds of evidence are not considered reliable enough to ensure that any therapy actually works. Recently, EDTA was shown to reduce health care costs as much as 95% in patients with chronic renal insufficiency, returning kidney function to baseline. Chelation is making a major scientific comeback due to the recent understanding of metal toxicity and its relationship to hypertension, vascular disease, chronic illness, and cancer. It is hoped that removal of these excessive metals in the body will reduce the illness experienced due to them. EDTA is FDA approved for removal of toxic metals.