Talk to your doctor, soy can be very constipating, its why thay say not to switch without talking to your doctor first. Here they do at least. It has something to do with the protiens in it. It may also just be that it has to much iron. But talk to your doctor he'll be more helpful. My friends LO had the same problem when she had to switch her LO to soy, I think her doctor said to add extra water, I'm not sure. Try not to give supository's to often as LO's can become dependent on them very quickly. If its that babd my doctor had us use prune juice.