Psyllium
"My son has suffered with major constipation for almost a year. He is 2 years old. Every doctor told us to use prunes, apple juice, no dairy... etc. we tried them all. BUT Metamucil has worked its wonders!! He poops everyday and does not have to strain so much. Its doing really good, we give him half of a teaspoon in his water once a day and he doesn't even drink all of it."