Sometimes, people have poop that's so dark it looks black. It might also have a sticky consistency, like that of tar. If your poop is black, it might be due to a change in your diet, a new medicine ...
The normal poop of a healthy breastfed baby is brownish yellow or green, seedy, and sometimes slightly runny. However, in the first few days after delivery, the baby may pass thick, blackish stools.