Chelation (say "key-LAY-shun") therapy is a medicine treatment for removing poisonous metals, such as lead, from the body. It also may be used to remove excess iron from the blood.

During chelation therapy, the person takes or has an injection of a medicine (chelating agent) that binds to the metal. The medicine and metal are then removed from the body through the urine. Chelation therapy also removes metals (like iron) that the body needs. So chelation therapy must be done carefully.

Chelation therapy can be used to treat severe lead poisoning. It also may be used to treat iron overload in people who need frequent blood transfusions, which can create organ-damaging excesses of iron. (People who have conditions such as thalassemia often receive blood transfusion therapy.)