Meconium Greenish-black, tarry, sticky stool that looks like motor oil Meconium is made up of amniotic fluid, mucus, skin cells, and other stuff ingested in utera. This is usually passed out within 24 hours after birth. Transitional stool Dark green-brown and less sticky When baby is 2-4 days old and start digesting early breast-milk or formula, baby is likely to pass out transitional stool Breastfeed stool Seedy yellow or slightly green stool with a mushy or creamy consistency, sweet smelling If baby is breastfeed, the stool will indicate that he/she is not receiving mature breast-milk instead of colostrum or transitional milk. It may be runny enough to resemble diarrhea. Stool color may vary depending on what you are (high-iron). If you see bright green and frothy stool, your baby is getting too much foremilk (the low calorie milk that comes first in a feeding), and not enough ...