This article outlines the research showing that children with autism have problems with digestion, and that treating these problems can improve the symptoms of autism.

The authors describe a large number of studies showing that children with autism have more problems with digestion than other children. These problems include gas, constipation, bloating, and â??tummy aches.â? More serious problems include swelling and inflammation of the stomach and intestines. Further, many children with autism even without symptoms of digestive problems, have more â??leakyâ? intestines than normal. This means that the by-products of digestion can move into the bloodstream, even when they are supposed to be excreted as waste. The authors then outline the theory that by-products made from grain and milk proteins can leak into the rest of the body, affecting the brain and behavior much like a drug would. However, while there is some evidence that gluten- and casein-free diets can help improve the behavior of children with autism, the authors suggest that it is not strong.