The best natural remedies that have worked for us is to first avoid foods that cause constipation like bananas and cheese.
The best non-prescription remedy that we have found is the Russell Stover Sugar Free Jelly Beans. Start off with 5 jelly beans and if that
doesn't work go to 10. I kid you not, it works for us every time and our daughter is 20 months old. Its also not too hard to get a baby to eat a jelly bean. I think it works because of the sugar alcohol. If you look on the back of the bag it even tells you that the product may cause a laxative effect.