Chelation therapy is the use of chelating agents to remove heavy metal ions from the body. Chelation (pronounced Kee la shun) therapy started during World War I when poison gas (Lewisite) affected soldiers were treated with a chelating agent Dimercapol also known as British Anti Lewisite (BAL). BAL had severe and painful side effects but was the only known antidote for the arsenic based poison gas at that time.

With the advancement in medicines many chelating agents were developed in the US, USSR and England which do not have as severe side effects as BAL. There are other chelating agents which have been developed to nullify the effects of harmful metallic ions. Some of them are:

BAL : British Anti Lewisite
EDTA : Dietheylene triamine pentaacetic acid
DMSA : Dimercaptosuccinic acid
DMPS : Dimercapto-propane sulfonate
ALA: Alpha lipoic acid
Ca Na2 ?EDTA : Calcuium disodium versante
D-Penicillamine
Deferosamine
Deferoxamine

Chelation therapy is conventionally used for treatment of heavy metal poisoning like mercury, arsenic, plutonium, lead and iron, (as in thalassemia). It is only used in acute cases where the poisoning is so high as to justify chelation therapy. The chelating agents are treated orally or intravenously or intramuscularly depending on the type of poisoning. Chelation therapy is also used for treatment of atherosclerosis (hardening of the arteries), autism caused by mercury by alternative medicine practitioners but the efficacy of chelation therapy is not proven for these ailments. Chelation therapy involves undergoing 20 to 50 infusions depending on the type of patient.

Chelating agents work by forming a water soluble compound with the harmful metal ions in the blood. This water soluble compound flows through the blood stream and is cleaned by kidneys and the liver.

It has been claimed widely that Chelation therapy is efficacious in treatment of people with fatty buildups of plaque in their arteries (atherosclerosis). Atherosclerosis is the main cause of heart attack and stroke where in fatty deposits in the arteries constrict the arteries. Calcium is a constituent of this fatty deposit. Chelation therapists claim that the chelating agents remove the calcium from the deposit and thus the artery gets cleared. However the problem with this theory is that the chelating agent cannot penetrate the cell wall and get to the calcium deposit. Further the chelating agent has more affinity for other ions than for calcium.
The proponents of chelation therapy like American College for Advancement of Medicine ACAM (a private organization) and few parent organizations have widely supported Chelation therapy. One example of successful use of chelation therapy is of Mr.Harold Mc Cluskey a nuclear worker who had been poisoned by americium and was later treated successfully by chelation therapy. Further high sulfur foods like onions, garlics, seaweeds etc,. are being used as ?chelating agents? due to folklore. MSM and NAC have also been used as sulfur supplements. However they are not chelating agents as the double bond with the metal ion is not involved and these compounds have mono thiols whereas chelating agents have di-thiols.
The opponents of chelation therapy have pointed to the dangers of chelation therapy like hypocalcaemia and mainstream medicine has rejected the claims of chelation therapists. Caution is advised before undergoing chelation therapy.