Switching from Enfamil to Similac?

It could take some time mainly because the juice you bought is probably more apple than prune. You might want to consider looking for a juice that is just prunes and maybe just dilute it a bit with water. More than likely the Similac has more iron in it and that's what is consitipating the baby. You might want to ask your doctor about what you should do in the future, because if it's the iron and she keeps drinking it, she will keep having the same problem.