Certain foods and medicines can cause black stool. Sometimes, black stool may even signal bleeding in the digestive tract. Learn when to see a doctor for black stool.

Meconium – your baby's first poop – is very dark green, looking almost black. It's made up of amniotic fluid, skin cells, lanugo (the fine hair that covered your baby's body), and mucus.

green, clay-colored, and yellow. Here's a breakdown of what each one means, according to Dr. Robbins: Black poop "may be caused by iron supplements, Pepto-Bismol, or dark foods," says Dr. Robbins.