Black poop can be harmless, caused by certain foods or medications, or it can be a sign of melena, meaning there’s blood in your stool. Melena happens when bleeding occurs in the upper digestive tract ...

Mucus in stool is normal, but it's not usually visible to the naked eye. When it is, you may notice stringy clear, white, or yellow goop in the toilet or clinging to your poop. It may be blood-tinged, ...