We report three children with autistic spectrum disorders who underwent upper 
gastrointestinal endoscopy and intravenous administration of secretin to 
stimulate pancreaticobiliary secretion. All three had an increased 
pancreaticobiliary secretory response when compared with nonautistic patients 
(7.5 to 10 mL/min versus 1 to 2 mL/min). Within 5 weeks of the secretin 
infusion, a significant amelioration of the children's gastrointestinal symptoms 
was observed, as was a dramatic improvement in their behavior, manifested by 
improved eye contact, alertness, and expansion of expressive language. These 
clinical observations suggest an association between gastrointestinal and brain 
function in patients with autistic behavior.