An article titled "Treatment with 'friendly' bacteria could counter autism in children" leads off with this paragraph:
PROBIOTIC bacteria given to autistic children improved their concentration and behaviour so much that medical trials collapsed because parents refused to accept placebos, a scientist revealed yesterday.
The effect of the bacteria was so pronounced that some of the parents taking part in what was supposed to be a blind trial realised their children were taking something other than a placebo.
A number then refused to give their children the placebo when they were due to switch, resulting in the collapse of the trial.
Note: There are many different "probiotics"--if you're seeking help with autism, please educate yourself before buying anything. One reference source is Pam Ferro who runs the clinic below. The clinic also has clinical guidelines for health care practitioners.
Hopewell Associates, Inc.
2 Brandt Island Road
Mattapoisett, MA 02719