This study examined the difference between sulfhydryl-reactive metals (mercury, lead, arsenic, and cadmium) in the hair of 45 children with autism (1-6 yr of age) as compared to 45 gender-, age-, and race-matched typical children. Hair samples were measured with inductively coupled mass spectrometry. Some studies, such as Holmes et al. (2003), suggested that children with autism may be poor detoxifiers relative to normally developing children. Metals that are not eliminated sequester in the brain. Our study found that arsenic, cadmium, and lead were significantly lower in the hair of children with autism than in matched controls. Mercury was in the same direction (lower in autism) following the same pattern, but did not achieve statistical significance. The evidence from our study supports the notion that children with autism may have trouble excreting these metals, resulting in a higher body burden that may contribute to symptoms of autism.