I have a 6 year old son who has had diarrhea since as long as I can remember. We've switched pediatricians, been to 2 pediatric GI doctors, and we're not getting any answers. My son is very short for his age, he is the height and weight of the average 4 year old. I have 3 other children, and they're all fine. We've ruled out Crohn's, Celiac, Cystic Fibrosis, and tons of other things. Numerous blood tests, a colonoscopy and 2 endoscopies.