Digestive enzymes are proteins which help to break down food so that the body can absorb it.
There are numerous different digestive enzymes including Bromelain, DMG, Dipeptidyl Peptidase, and Papain.
The supporters of digestive enzymes claim that children with autism sometimes have low levels of certain enzymes, or less active enzymes, or both.
They also claim that enzyme problems are especially common in children with gastrointestinal problems, such as chronic constipation or diarrhea.
Some people go further and claim that impaired digestive function may cause or exacerbate some of the symptoms of autism.