Many parents choose soy formula for a variety of reasons. Soy formula has been known to cause green stools that should subside within a few weeks and become more consistent.
In general, green stool simply means that the stool is passing through the bady faster than normal. That could be as a result of the soy, but sometimes babies' stool is just green.
I don't think they necessarily should have a geen stool, but it's okay. It just depends on how they digest it, so some babies may have a green stool from soy or other formula and some may not.
Unless they're black or red, it's probably no cause for alarm. If the stools are constantly green or the baby is constipated or has diarrhea, call the pediatrician.
