Denise,
The suggestion about the herbal aloe is spot on. I would also suggest yogurt (acidophilus cultures aid in intestinal health) and Flax Seed Oil.
When we moved to a different house this year my son (almost 4) developed cronic constipation due to stresses (we believe). He had bloody stools, pain, etc. It took a good month to regulate him, but we cut out a lot of dairy (gave soy milk, no cheese, etc) and gave him the aloe and flax seed oil, kept him drinking water and he cleared up. You can mix it into juice, apple sauce, whatever. Also oatmeal and whole grains, vegis. My kids are healthy eaters anyway (my son asks for broccoli at restaurants!) so his diet was basically sound. But the aloe and flax will do just as good a job as drugs without the nasty side effects.
Also, if you have a child who is just starting solids and gets constipated I reccomend STRONGLY getting the book SUPER BABY FOOD and learning how to make your own baby cereal. It take so little time (REALLY!) and it's healthier, cheaper and they don't get bound up by the processed junk. Also, try the flax oil in the baby food for baby constipation. works wonderfully, gently, and it's really good for them.
H.