What are some causes of dark red blood in stool almost black

Hi, Anon.

Thank you for posting.

Red or black colored stool may be a sign of bleeding in the GI tract (from the esophagus, stomach, small intestine or colon) and should be evaluated by your doctor.

When stool color changes, what tests need to be done depends upon what cause is suspected for the stool color change. For example, gastrointestinal (GI) endoscopy may be required to evaluate red or black stools if bleeding is suspected.

Helena