The director of U.S. National Institute of Mental Health, pressured by the anxious parents of children with autism, is advocating testing chelation therapy as a treatment for the little-understood neurological disorder, the Associated Press reported Wednesday.

Chelation therapy aims to purge the body of heavy metals. Its use in children with autism is based on the unproven notion that mercury in the vaccines is responsible for cases of the disorder, the AP reported. With the exception of certain flu shots, mercury hasn't been used in pediatric vaccines since 2001.