Introduction
Autism or Autistic Spectrum Disorder (ASD) is a Pervasive Developmental Disorder (PDD) with abnormal or impaired development in reciprocal social interaction, abnormal or impaired social communication and social imagination. Recent theories focused on the possibility of autism being linked with gastrointestinal (GI) abnormalities. Moreover, the problem behaviour typical of autism might be linked to the underlying medical symptoms such as abdominal pain, diarrhoea, and bloating typical of GI dysfunction.