In one sentence
A 2015 Cochrane review found no evidence that chelation therapy — drugs meant to remove heavy metals from the body — improves autism symptoms, and the authors warn that known risks outweigh any proven benefit.
What the researchers did
Some parents and practitioners have tried chelation for autistic children based on the idea that heavy metals cause or worsen autism symptoms. Chelation uses pharmaceutical agents to bind metals so the body can excrete them.
Researchers searched medical databases through November 2014 for randomised controlled trials comparing chelating drugs with placebo in people with autism spectrum disorder. Nine non-randomised studies were excluded.
Only one trial met their criteria. It had two phases. In phase one, 77 autistic children received either glutathione lotion or placebo for seven days, followed by three days of oral DMSA (a chelating drug). The 49 children who excreted high levels of heavy metals in phase one continued to phase two, where they received repeated cycles of oral DMSA or placebo for up to six rounds.
What they found
In the only included trial, repeated courses of oral DMSA did not improve autism symptoms compared with placebo.
The study was small — only 49 children in phase two — and had methodological limitations, including incomplete outcome data.
No other randomised trials were available for review. The authors note that earlier reports have linked chelation therapy to serious adverse events, including dangerously low calcium levels, kidney impairment, and at least one death.
What this means for families and therapists
Chelation is sometimes marketed as an autism treatment, but this review did not find clinical trial evidence that it helps autistic children.
Given the reported risks, families should treat chelation with caution and discuss any proposed treatment plan with a qualified clinician. Evidence-based behavioral, communication, and educational supports remain the foundation of care.
If a child is already receiving chelation or similar unproven treatments, sharing that information with the medical team is important for safety monitoring.
Limitations and what we don't know yet
The evidence base rests on a single small trial with design weaknesses, so conclusions are limited.
Phase two included only children who were high excreters of heavy metals, so results may not apply to all autistic children. Long-term follow-up was not available. This review is from 2015; no stronger randomised evidence has been added since then.
This is a simplified summary of Chelation for autism spectrum disorder (ASD) by James S, Stevenson S.W, Silove N, Williams K, Cochrane Database of Systematic Reviews (2015).
Source license: CC-BY-NC-4.0.
This is not medical advice. Please consult a qualified healthcare professional before making treatment decisions.