What kind of foods are best for children with constipation problems. yogurt vs greek yogurt, supplements or other? what foods are to be avoided?

Depends on age: This depends on the age of the child, if there are any underlying medical problems, and what the reason for the constipation is. You should have an evaluation with your pediatrician for an examination and discussion of constipation treatment. Occasionally, referral to a pediatric gastroenterologist is needed. start with discussion with your pediatrician.

Constipation: Probiotics are helpful, but I prefer a diet high in fiber. Think figs, prunes, sweet potatoes, whole grains (Multigrain Cheerios, breads), and just about any vegetable you can get them to eat. Greek yogurt is all the rage regarding fats, but I would simply just steer away from artificial flavors and colors (and let's not forget about high fructose corn syrup). I also like molasses.