I have gone through the same thing with my toddler. Have you tried V8 Splash-Tropical Blend? I give my son 2 slightly watered down cups a day. His stool is much softer and easy to pass. There is a big difference when he goes without. It contains mango juice which seems to have a laxative effect. Also for some strange reason bananas cause him to have a soft bm. I know these are constipating for almost everybody. This may not help but it's worth a try. Let me know if it helps.