Autism Spectrum Disorders are currently estimated to effect 1 in 68 children. There are many different genetic, environmental and biological factors that may lead to autism; however, there is no cure. Recently, a link between gut microbes and autism was discovered. Can knowing the identity of the bacteria living in our guts help us to diagnose and treat autism? This lecture will review current research on the identification of gut microbes in children with autism and the potential use of probiotics and vaccines as a treatment.