It's unclear whether chelation therapy can treat heart disease.

Chelation therapy has long been used as a treatment for mercury and lead poisoning, but it isn't a proven treatment for heart disease. It can potentially cause serious side effects when used as a heart disease treatment. Even so, some people have received chelation therapy to treat heart disease and stroke.

Chelation therapy involves weekly treatments of ethylenediaminetetraacetic acid (EDTA) given in a vein. Each treatment lasts from 30 minutes to up to several hours.

In general, the medicine finds and sticks to metals and minerals in the bloodstream. This action creates a substance that leaves the body in the urine. Some researchers say chelation therapy can treat heart disease because the medicine may stick to — and remove — calcium found in deposits that clog arteries.

However, chelation therapy for heart disease remains controversial.

Here's what is known so far:

• The Trial to Assess Chelation Therapy (TACT) didn't provide enough evidence to support routine use of this treatment for heart disease. But it did find that chelation therapy offered moderate protection against future cardiovascular events, such as stroke and heart attack, in those with diabetes. Another study, TACT2, will focus specifically on people with diabetes.
• The American Heart Association and the American College of Cardiology say it's uncertain whether chelation therapy is helpful as a treatment for heart disease.
• The Food and Drug Administration hasn't approved chelation therapy for use as a heart disease treatment.

Chelation therapy for heart disease has known risks and side effects. The most common is burning at the vein site where the medicine is given. Other side effects include fever, headache, nausea or vomiting.

Rare but serious complications of chelation therapy for heart disease that have been reported include:

• Low blood-calcium levels.
• Sudden drop in blood pressure.
• Drop in the number of blood cells made in bone marrow.
• Heart failure.
• Kidney damage.
• Death.

Before trying chelation therapy as a heart disease treatment, talk to your health care team about the benefits and risks.