Chelation therapy is a treatment that is used to treat heavy metal poisoning. It most often involves the injection of ethylene diamine tetraacetic acid (EDTA) - also refered to as a 'synthetic amino acid' - that binds with (chelates) heavy metals, which include iron, lead, mercury, cadmium, and zinc. The term ‘chelation’ comes from the Greek word ‘chele’ which means claw, referring to the way the chemical grabs onto these metals. EDTA is a man-made amino acid, which has a particular affinity for toxic metals such as mercury, cadmium, aluminium and lead.