What Dr. Campbell-McBride is talking about here is nothing more than a variant of the ancient concept of autointoxication, whereby our own human waste products "poison" us. The difference is that she's attributing it to bacteria living in our gut. But where do many of the bacteria living in your gut end up? In your poop, of course! In any case, Campbell-McBride even has a name for her invented autism syndrome: Gut and Psychology Syndrome (GAPS). She's even developed a whole cottage industry of dietary woo to treat it, which can be found on various websites, including Gut and Psychology Syndrome, The GAPS Diet, and in her book Gut and Psychology Syndrome Book: Natural Treatment For: Autism, ADD, ADHD Depression, Dyslexia, Dyspraxia, Schizophrenia. And, of course, she has her own website and if you check it out you'll see that she claims to be able to treat anything from acne to depression to diabetes to autism to ADHD to schizophrenia to tummy pain.