DD was transitioned from bm to formula - little at a time over a few weeks - but when we went 100% formula, she got majorly stopped up. Went 3-4 days w/no poop, so pedi had us do diluted white grape juice (warmed) - didn't help. Rectal temp - didn't help. Then we did the glycerin (infants) suppository. THAT HELPED. Of course. But after that initial-reaction poop (that's hard and huge and omgz) she goes another 3-4 days.. just did the second suppository in a week. How long should it really take them to get used to the switch??? I am feeling SUCH crippling guilt over this - because I am the one who caused it, is what I feel like! I took away the bm and intro'd formula, thus causing her to go cross-eyed over trying to poop so hard!